1.
Laboratory
–
A laboratory is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratories used for scientific research take many forms because of the requirements of specialists in the various fields of science. A physics laboratory might contain a particle accelerator or vacuum chamber, a chemist or biologist might use a wet laboratory, while a psychologists laboratory might be a room with one-way mirrors and hidden cameras in which to observe behavior. In some laboratories, such as commonly used by computer scientists. Scientists in other fields will use other types of laboratories. Engineers use laboratories as well to design, build, and test technological devices, scientific laboratories can be found as research and learning spaces in schools and universities, industry, government, or military facilities, and even aboard ships and spacecraft. Early instances of laboratories recorded in English involved alchemy and the preparation of medicines, larger or more sophisticated equipment is generally called a scientific instrument. Both laboratory equipment and scientific instruments are increasingly being designed and shared using open hardware principles, open source labs use open source scientific hardware. The title of laboratory is used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories. In many labs, though, hazards are present, in laboratories where dangerous conditions might exist, safety precautions are important. Rules exist to minimize the risk, and safety equipment is used to protect the lab user from injury or to assist in responding to an emergency. This standard is referred to as the Laboratory Standard. Under this standard, a laboratory is required to produce a Chemical Hygiene Plan which addresses the specific hazards found in its location, the CHP must be reviewed annually. Many schools and businesses employ safety, health, and environmental specialists, such as a Chemical Hygiene Officer to develop, manage, and evaluate their CHP. Additionally, third party review is used to provide an objective outside view which provides a fresh look at areas. An important element of such audits is the review of regulatory compliance, training is critical to the ongoing safe operation of the laboratory facility. Educators, staff and management must be engaged in working to reduce the likelihood of accidents, injuries, efforts are made to ensure laboratory safety videos are both relevant and engaging. The dictionary definition of laboratory at Wiktionary Media related to Laboratory at Wikimedia Commons Nobel Laureates Interactive 360° Laboratories
2.
Separation of a mixture
–
A separation process is a method to achieve any phenomenon that converts a mixture of chemical substance into two or more distinct product mixtures, which may be referred to as mixture. At least one of which is enriched in one or more of the mixtures constituents, in some cases, a separation may fully divide the mixture into its pure constituents. Separations differ in properties or physical properties such as size, shape, mass, density, or chemical affinity. They are often classified according to the differences they use to achieve separation. Usually there is physical movement and no substantial chemical modification. If no single difference can be used to accomplish a desired separation, with a few exceptions, elements or compounds are naturally found in an impure state. Often these impure raw materials must be separated into their purified components before they can be put to productive use, crude oil occurs naturally as a mixture of various hydrocarbons and impurities. In both of these cases, a series of separations is necessary to obtain the end products. In the case of oil refining, crude is subjected to a series of individual distillation steps. Separators are used for the separation of liquid, in fact, they are vertically supported centrifuges and are built with flying bearings. A separator belongs to the continues sedimentation centrifuges, both the purified liquid and the liquid separated from each other are continuously discharged by using a pump or pressure free. The solid material can be discharged discontinuously, pseudo continuously or continuously, the drum is the centerpiece of the separator, in which the separation process takes place. There are two types of drums, the drum and the disc drum. The power transmission on the spindle and thereby on the drum can take place by using one of the three motors, helical gears, a belt drive or direct drive, via a special motor. The sealing of the separators is differentiated into four types, open, semi-closed and this high voltage is used to separate the ionized particles
3.
Partition coefficient
–
In the physical sciences, a partition-coefficient or distribution-coefficient is the ratio of concentrations of a compound in a mixture of two immiscible phases at equilibrium. This ratio is therefore a measure of the difference in solubility of the compound in two phases. In the chemical and pharmaceutical sciences, both phases usually are solvents, most commonly, one of the solvents is water while the second is hydrophobic such as 1-octanol. Hence the partition coefficient measures how hydrophilic or hydrophobic a chemical substance is, partition coefficients are useful in estimating the distribution of drugs within the body. Hydrophobic drugs with high octanol/water partition coefficients are distributed to hydrophobic areas such as lipid bilayers of cells. Conversely hydrophilic drugs are primarily in aqueous regions such as blood serum. If one of the solvents is a gas and the other a liquid, for example, the blood/gas partition coefficient of a general anesthetic measures how easily the anesthetic passes from gas to blood. Partition coefficients can also be defined one of the phases is solid, for instance, when one phase is a molten metal. The partitioning of a substance into a solid results in a solid solution, partition coefficients can be measured experimentally in various ways or estimated via calculation based on a variety of methods. Despite formal recommendation to the contrary, the partition coefficient remains the predominantly used term in the scientific literature. In contrast, the IUPAC recommends that the term no longer be used, rather. When one of the solvents is water and the other is a non-polar solvent, for measurements of distribution coefficients, the pH of the aqueous phase is buffered to a specific value such that the pH is not significantly perturbed by the introduction of the compound. In addition, since log D is pH-dependent, the pH at which the log D was measured must be specified. In areas such as drug discovery—areas involving partition phenomena in systems such as the human body—the log D at the physiologic pH,7.4, is of particular interest. It is often convenient to express the log D in terms of P I, defined above, the values in the following table are from the Dortmund Data Bank. They are sorted by the coefficient, smallest to largest. Values for other compounds may be found in a variety of available reviews, critical discussions of the challenges of measurement of log P, and related computation of its estimated values, appear in several reviews. Hence, the log P of a molecule is one used in decision-making by medicinal chemists in pre-clinical drug discovery, for example
4.
Ancient Greek
–
Ancient Greek includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often divided into the Archaic period, Classical period. It is antedated in the second millennium BC by Mycenaean Greek, the language of the Hellenistic phase is known as Koine. Koine is regarded as a historical stage of its own, although in its earliest form it closely resembled Attic Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects, Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical phases of the language, Ancient Greek was a pluricentric language, divided into many dialects. The main dialect groups are Attic and Ionic, Aeolic, Arcadocypriot, some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are also several historical forms, homeric Greek is a literary form of Archaic Greek used in the epic poems, the Iliad and Odyssey, and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic, the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period and they have the same general outline, but differ in some of the detail. The invasion would not be Dorian unless the invaders had some relationship to the historical Dorians. The invasion is known to have displaced population to the later Attic-Ionic regions, the Greeks of this period believed there were three major divisions of all Greek people—Dorians, Aeolians, and Ionians, each with their own defining and distinctive dialects. Often non-west is called East Greek, Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, thessalian likewise had come under Northwest Greek influence, though to a lesser degree. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, and Northern Peloponnesus Doric. The Lesbian dialect was Aeolic Greek and this dialect slowly replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek, by about the 6th century AD, the Koine had slowly metamorphosized into Medieval Greek
5.
Color
–
Color or colour is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. This perception of color derives from the stimulation of cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them and this reflection is governed by the objects physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically by coordinates, there may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the dimensions relates to a colours colorfulness). The photo-receptivity of the eyes of species also varies considerably from our own. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red, papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the kingdom has been found in stomatopods with up to 12 spectral receptor types thought to work as multiple dichromatic units. The science of color is sometimes called chromatics, colorimetry, or simply color science and it includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range. Electromagnetic radiation is characterized by its wavelength and its intensity, when the wavelength is within the visible spectrum, it is known as visible light. Most light sources emit light at different wavelengths, a sources spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, in each such class the members are called metamers of the color in question. The table at right shows approximate frequencies and wavelengths for various pure spectral colors, the wavelengths listed are as measured in air or vacuum. A common list identifies six main bands, red, orange, yellow, green, blue, Newtons conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, the color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Some objects not only light, but also transmit light or emit light themselves. This effect is known as color constancy, opaque objects that do not reflect specularly have their color determined by which wavelengths of light they scatter strongly. If objects scatter all wavelengths with roughly equal strength, they appear white, if they absorb all wavelengths, they appear black. Opaque objects that reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences
6.
History of chromatography
–
The history of chromatography spans from the mid-19th century to the 21st. Chromatography, literally color writing, was used—and named— in the first decade of the 20th century, primarily for the separation of plant pigments such as chlorophyll and carotenoids. New forms of chromatography developed in the 1930s and 1940s made the technique useful for a range of separation processes and chemical analysis tasks. According to historical analysis of L. S. Ettre, however, in the 1860s, Christian Friedrich Schönbein and his student Friedrich Goppelsroeder published the first attempts to study the different rates at which different substances move through filter paper. Unlike modern paper chromatography, capillary analysis used reservoirs of the substance being analyzed, work on capillary analysis continued, but without much technical development, well into the 20th century. The first significant advances over Goppelsroeders methods came with the work of Raphael E, in 1900, he reported his findings at the First International Petroleum Congress in Paris, where they created a sensation. The first true chromatography is usually attributed to the Russian-Italian botanist Mikhail Tsvet, Tsvet applied his observations with filter paper extraction to the new methods of column fractionation that had been developed in the 1890s for separating the components of petroleum. He used a column containing calcium carbonate to separate yellow, orange. The method was described on December 30,1901 at the 11th Congress of Naturalists, the first printed description was in 1903, in the Proceedings of the Warsaw Society of Naturalists, section of biology. He first used the term chromatography in print in 1906 in his two papers about chlorophyll in the German botanical journal, Berichte der Deutschen Botanischen Gesellschaft, in 1907 he demonstrated his chromatograph for the German Botanical Society. In a 1903 lecture, Tsvet also described using filter paper to approximate the properties of living plant fibers in his experiments on plant pigments—a precursor to paper chromatography and he found that he could extract some pigments from leaves with non-polar solvents, but others required polar solvents. He reasoned that chlorophyll was held to the plant tissue by adsorption, to test this, he applied dissolved pigments to filter paper, allowed the solvent to evaporate, then applied different solvents to see which could extract the pigments from the filter paper. He found the pattern as from leaf extractions, carotene could be extracted from filter paper using non-polar solvents. Tsvets work saw little use until the 1930s, Martin, who had previously been working in vitamin chemistry, began collaborating with Synge in 1938, brought his experience with equipment design to Synges project of separating amino acids. Martin and Synge demonstrated the potential of the methods by separating amino acids marked in the column by the addition of methyl red, in a series of publications beginning in 1941, they described increasingly powerful methods of separating amino acids and other organic chemicals. In pursuit of better and easier methods of identifying the amino acid constituents of peptides, Martin, a short abstract in 1943 followed by a detailed article in 1944 described the use of filter paper as the stationary phase for performing chromatography on amino acids, paper chromatography. By 1947, Martin, Synge and their collaborators had applied this method to determine the sequence of Gramicidin S. These and related paper chromatography methods were also foundational to Fred Sangers effort to determine the amino acid sequence of insulin, Martin, in collaboration with Anthony T. James, went on to develop gas chromatography beginning in 1949
7.
Mikhail Tsvet
–
Mikhail Semyonovich Tsvet was a Russian-Italian botanist who invented adsorption chromatography. His last name is Russian for both colour and flowering, Mikhail Tsvet was born March 21st 1872 in Asti, Italy. His mother was Italian, and his father was a Russian official and his mother died soon after his birth, and he was raised in Geneva, Switzerland. He received his B. S. degree from the Department of Physics and Mathematics at the University of Geneva in 1893, however, he decided to dedicate himself to botany and received his Ph. D. degree in 1896 for his work on cell physiology. He moved to Saint Petersburg, Russia, in 1896 because his father was recalled from the foreign service, there he started to work at the Biological Laboratory of the Russian Academy of Sciences. His Geneva degrees were not recognized in Russia, and he had to earn Russian degrees, in 1897 he became a teacher of botany courses for women. In 1902 he became an assistant at the Institute of Plant Physiology of the Warsaw University in Poland. In 1903 he became an assistant professor and taught also at other Warsaw universities, after the beginning of World War I the Warsaw University of Technology was evacuated to Moscow, Russia, and in 1916 again to Gorki near Moscow. In 1917 he became a Professor of Botany and the director of the gardens at the University of Tartu in Estonia. In 1918 when German troops occupied the city, the university was evacuated to Voronezh, Tsvet died of a chronic inflammation of the throat on 26 June 1919 at the age of 47. Mikhail Tsvet invented chromatography in 1900 during his research on plant pigments and he used liquid-adsorption column chromatography with calcium carbonate as adsorbent and petrol ether/ethanol mixtures as eluent to separate chlorophylls and carotenoids. The method was described on 30 December 1901 at the XI Congress of Naturalists, the first printed description was in 1905, in the Proceedings of the Warsaw Society of Naturalists, biology section. О новой категории адсорбционных явлений и о применении их к биохимическому анализу, Труды Варшавского общества естествоиспытателей, отделении биологии and he first used the term chromatography in print in 1906 in his two papers about chlorophyll in the German botanical journal, Berichte der Deutschen botanischen Gesellschaft. In 1907 he demonstrated his chromatograph for the German Botanical Society, Richard Willstätter and Arthur Stoll tried to repeat Tsvets experiments, but because they used an overly aggressive adsorbent, were not able to do so. They published their results and Tsvets chromatography method fell into obscurity and it was revived 10 years after his death thanks to Austrian biochemist Richard Kuhn and his student, German scientist Edgar Lederer as well as the work of A. J. Martin and R. L. Synge. The standard botanical author abbreviation Tswett is applied to plants that he described, Симон Шноль, Герои и злодеи советской науки, Moscow, Kron-press,1997 E. M. Senchenkova, Tsvet, Mikhail Semenovich. PMID4885242 Biography of Mikhail S. Tsvet Mikhail S. Tsvet, Physical chemical studies on chlorophyll adsorptions Berichte der Deutschen botanischen Gesellschaft 24, 316–323
8.
Pigment
–
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, many materials selectively absorb certain wavelengths of light. Materials that humans have chosen and developed for use as pigments usually have properties that make them ideal for coloring other materials. A pigment must have a high tinting strength relative to the materials it colors and it must be stable in solid form at ambient temperatures. For industrial applications, as well as in the arts, permanence, pigments that are not permanent are called fugitive. Fugitive pigments fade over time, or with exposure to light, pigments are used for coloring paint, ink, plastic, fabric, cosmetics, food, and other materials. Most pigments used in manufacturing and the arts are dry colorants. This powder is added to a binder, a neutral or colorless material that suspends the pigment. A distinction is made between a pigment, which is insoluble in its vehicle, and a dye, which either is itself a liquid or is soluble in its vehicle. A colorant can act as either a pigment or a dye depending on the vehicle involved, in some cases, a pigment can be manufactured from a dye by precipitating a soluble dye with a metallic salt. The resulting pigment is called a lake pigment, the term biological pigment is used for all colored substances independent of their solubility. In 2006, around 7.4 million tons of inorganic, organic, asia has the highest rate on a quantity basis followed by Europe and North America. By 2020, revenues will have risen to approx, the global demand on pigments was roughly US$20.5 billion in 2009, around 1. 5-2% up from the previous year. It is predicted to increase in a growth rate in the coming years. The worldwide sales are said to increase up to US$24.5 billion in 2015, pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of visible light. White light is an equal mixture of the entire spectrum of visible light with a wavelength in a range from about 375 or 400 nanometers to about 760 or 780 nm. When this light encounters a pigment, parts of the spectrum are absorbed by the molecules or ions of the pigment, in organic pigments such as diazo or phthalocyanine compounds the light is absorbed by the conjugated systems of double bonds in the molecule. Some of the inorganic pigments such as vermilion or cadmium yellow absorb light by transferring an electron from the ion to the positive ion
9.
Chlorophyll
–
Chlorophyll is any of several closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants. Its name is derived from the Greek words χλωρός, chloros and φύλλον, chlorophyll is essential in photosynthesis, allowing plants to absorb energy from light. Chlorophyll absorbs light most strongly in the portion of the electromagnetic spectrum. Conversely, it is a poor absorber of green and near-green portions of the spectrum, chlorophyll molecules are specifically arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. Two types of chlorophyll exist in the photosystems of green plants, chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. Chlorophyll is vital for photosynthesis, which plants to absorb energy from light. Chlorophyll molecules are arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. In these complexes, chlorophyll serves two primary functions, the two currently accepted photosystem units are photosystem II and photosystem I, which have their own distinct reaction centres, named P680 and P700, respectively. These centres are named after the wavelength of their red-peak absorption maximum, the identity, function and spectral properties of the types of chlorophyll in each photosystem are distinct and determined by each other and the protein structure surrounding them. Once extracted from the protein into a solvent, these chlorophyll pigments can be separated into chlorophyll a, the function of the reaction center of chlorophyll is to absorb light energy and transfer it to other parts of the photosystem. The absorbed energy of the photon is transferred to an electron in a process called charge separation, the removal of the electron from the chlorophyll is an oxidation reaction. The chlorophyll donates the high energy electron to a series of molecular intermediates called a transport chain. The charged reaction center of chlorophyll is reduced back to its ground state by accepting an electron stripped from water. The electron that reduces P680+ ultimately comes from the oxidation of water into O2 and this reaction is how photosynthetic organisms such as plants produce O2 gas, and is the source for practically all the O2 in Earths atmosphere. Electron transfer reactions in the membranes are complex, however. NADPH is an agent used to reduce CO2 into sugars as well as other biosynthetic reactions. Thus, the other chlorophylls in the photosystem and antenna pigment proteins all cooperatively absorb, besides chlorophyll a, there are other pigments, called accessory pigments, which occur in these pigment–protein antenna complexes. Chlorophyll is a pigment, which is structurally similar to
10.
Carotene
–
The term carotene is used for many related unsaturated hydrocarbon substances having the formula C40Hx, which are synthesized by plants but in general cannot be made by animals. Carotenes are photosynthetic pigments important for photosynthesis and they absorb ultraviolet, violet, and blue light and scatter orange or red light, and yellow light. Carotenes are responsible for the colour of the carrot, for which this class of chemicals is named. Carotenes are also responsible for the colours in dry foliage. They also impart the yellow coloration to milk-fat and butter, the typical yellow-coloured fat of humans and chickens is a result of fat storage of carotenes from their diets. Carotenes contribute to photosynthesis by transmitting the energy they absorb to chlorophyll. They also protect plant tissues by helping to absorb the energy from singlet oxygen, the carotenes α-carotene and γ-carotene, due to their single retinyl group, also have some vitamin A activity, as does the xanthophyll carotenoid β-cryptoxanthin. All other carotenoids, including lycopene, have no beta-ring and thus no vitamin A activity, animal species differ greatly in their ability to convert retinyl containing carotenoids to retinals. Carnivores in general are poor converters of dietary ionone-containing carotenoids, chemically, carotenes are polyunsaturated hydrocarbons containing 40 carbon atoms per molecule, variable numbers of hydrogen atoms, and no other elements. Some carotenes are terminated by rings, on one or both ends of the molecule. All are coloured to the eye, due to extensive systems of conjugated double bonds. Structurally carotenes are tetraterpenes, meaning that they are synthesized biochemically from four 10-carbon terpene units, carotenes are found in plants in two primary forms designated by characters from the Greek alphabet, alpha-carotene and beta-carotene. Gamma-, delta-, epsilon-, and zeta-carotene also exist, since they are hydrocarbons, and therefore contain no oxygen, carotenes are fat-soluble and insoluble in water. 6 μg of dietary β-carotene supplies the equivalent of 1 μg of retinol and this is equivalent to 3⅓ IU of vitamin A. The two primary isomers of carotene, α-carotene and β-carotene, differ in the position of a bond in the cyclic group at one end. β-Carotene is the common form and can be found in yellow, orange. As a rule of thumb, the greater the intensity of the colour of the fruit or vegetable. Carotene protects plant cells against the effects of ultraviolet light
11.
Xanthophyll
–
Xanthophylls are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group, the other division is formed by the carotenes. The name is from Greek xanthos and phyllon, due to their formation of the band seen in early chromatography of leaf pigments. The molecular structure of xanthophylls is similar to that of carotenes, xanthophylls contain their oxygen either as hydroxyl groups and/or as pairs of hydrogen atoms that are substituted by oxygen atoms acting as a bridge. For this reason, they are more polar than the purely hydrocarbon carotenes, typically, carotenes are more orange in color than xanthophylls. The xanthophylls found in the bodies of animals, and in animal products, are ultimately derived from plant sources in the diet. For example, the color of chicken egg yolks, fat. These xanthophylls protect the eye from ionizing blue and ultraviolet light and these two specific xanthophylls do not function in the mechanism of sight, since they cannot be converted to retinal. Their arrangement is believed to be the cause of Haidingers brush, the group of xanthophylls includes lutein, zeaxanthin, neoxanthin, violaxanthin, flavoxanthin, and α- and β-cryptoxanthin. The latter compound is the only known xanthophyll to contain a beta-ionone ring, even then, it is a vitamin only for plant-eating mammals that possess the enzyme to make retinal from carotenoids that contain beta-ionone. In species other than mammals, certain xanthophylls may be converted to hydroxylated retinal-analogues that function directly in vision, the xanthophyll cycle involves the enzymatic removal of epoxy groups from xanthophylls to create so-called de-epoxidised xanthophylls. Non-photochemical quenching is one of the ways of protecting against photoinhibition. In higher plants, there are three carotenoid pigments that are active in the cycle, violaxanthin, antheraxanthin, and zeaxanthin. This conversion of violaxanthin to zeaxanthin is done by the enzyme violaxanthin de-epoxidase, in diatoms and dinoflagellates, the xanthophyll cycle consists of the pigment diadinoxanthin, which is transformed into diatoxanthin or dinoxanthin under high-light conditions. Xanthophylls are found in all young leaves and in etiolated leaves, examples of other rich sources include papaya, peaches, prunes, and squash, which contain lutein diesters. Demmig-Adams, B & W. W. Adams,2006, photoprotection in an ecological context, the remarkable complexity of thermal energy dissipation, New Phytologist,172, 11–21. Xanthophylls at the US National Library of Medicine Medical Subject Headings
12.
Archer Martin
–
Archer John Porter Martin, FRS was an English chemist who shared the 1952 Nobel Prize in Chemistry for the invention of partition chromatography with Richard Synge. Martin was educated at Bedford School, and the University of Cambridge, working first in the Physical Chemistry Laboratory, he moved to the Dunn Nutritional Laboratory, and in 1938 moved to Wool Industries Research Institution in Leeds. He was head of the division of Boots Pure Drug Company from 1946 to 1948. There, he was appointed head of the chemistry division of the National Institute for Medical Research in 1952. He specialised in biochemistry, in aspects of vitamins E and B2. He developed partition chromatography whilst working on the separation of amino acids, amongst many honours, he received his Nobel Prize in 1952. He published far fewer papers than the typical Nobel winners—only 70 in all—but his ninth paper won the Nobel, the University of Houston dropped him from its chemistry faculty in 1979 because he was not publishing enough. In 1943 he married Judith Bagenal, and together they had two sons and three daughters, in the last years of his life he suffered from Alzheimers disease. Martin was mentioned in the television series The Simpsons in the episode titled Flaming Moes. Character Martin Prince made reference to Martin while doing a presentation on the gas chromatograph
13.
Richard Laurence Millington Synge
–
Richard Laurence Millington Synge FRS was a British biochemist, and shared the 1952 Nobel Prize in Chemistry for the invention of partition chromatography with Archer Martin. Synge was educated at Winchester College and Trinity College, Cambridge, between 1942 and 1948 he studied peptides of the protein group gramicidin, work later used by Frederick Sanger in determining the structure of insulin. He was awarded an honorary Doctor of Science from the University of East Anglia in 1977, Synges Nobel Foundation biography Synges Nobel Lecture Applications of Partition Chromatography Sidney Elsden
14.
Nobel Prize in Chemistry
–
The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outstanding contributions in chemistry, physics, literature, peace, and physiology or medicine. This award is administered by the Nobel Foundation and awarded by Royal Swedish Academy of Sciences on proposal of the Nobel Committee for Chemistry which consists of five elected by Academy. The award is presented in Stockholm at a ceremony on December 10. The first Nobel Prize in Chemistry was awarded in 1901 to Jacobus Henricus van t Hoff, of the Netherlands, for his discovery of the laws of chemical dynamics and osmotic pressure in solutions. From 1901 to 2016, the award has been bestowed on a total of 174 individuals, though Nobel wrote several wills during his lifetime, the last was written a little over a year before he died, and signed at the Swedish-Norwegian Club in Paris on 27 November 1895. Nobel bequeathed 94% of his assets,31 million Swedish kronor, to establish. Due to the level of surrounding the will, it was not until April 26,1897 that it was approved by the Storting. The executors of his will were Ragnar Sohlman and Rudolf Lilljequist, the members of the Norwegian Nobel Committee that were to award the Peace Prize were appointed shortly after the will was approved. The prize-awarding organisations followed, the Karolinska Institutet on June 7, the Swedish Academy on June 9, the Nobel Foundation then reached an agreement on guidelines for how the Nobel Prize should be awarded. In 1900, the Nobel Foundations newly created statutes were promulgated by King Oscar II, according to Nobels will, The Royal Swedish Academy of Sciences were to award the Prize in Chemistry. The committee and institution serving as the board for the prize typically announce the names of the laureates in October. The prize is awarded at formal ceremonies held annually on December 10. The highlight of the Nobel Prize Award Ceremony in Stockholm is when each Nobel Laureate steps forward to receive the prize from the hands of His Majesty the King of Sweden, the Nobel Laureate receives three things, a diploma, a medal and a document confirming the prize amount. Later the Nobel Banquet is held in Stockholm City Hall, a maximum of three laureates and two different works may be selected. The award can be given to a maximum of three recipients per year and it consists of a gold medal, a diploma, and a cash grant. The Nobel Laureates in chemistry are selected by a committee that consists of five elected by the Royal Swedish Academy of Sciences. In its first stage, several people are asked to nominate candidates
15.
Paper chromatography
–
Paper chromatography is an analytical method used to separate colored chemicals or substances. It is primarily used as a tool, having been replaced by other chromatography methods. A paper chromatography variant, two-dimensional chromatography involves using two solvents and rotating the paper 90° in between and this is useful for separating complex mixtures of compounds having similar polarity, for example, amino acids. The mobile phase is a solution that travels up the stationary phase, the mobile phase is generally an alcohol solvent mixture, while the stationary phase is a strip of chromatography paper, also called a chromatogram. Rƒ values are expressed as a fraction of two decimal places. If Rƒ value of a solution is zero, the remains in the stationary phase. If Rƒ value =1 then the solute has no affinity for the stationary phase, to calculate the Rƒ value, take the distance traveled by the substance divided by the distance traveled by the solvent. For example, if a compound travels 9.9 cm and the solvent front travels 12.7 cm, Rƒ value depends on temperature and the solvent used in experiment, so several solvents offer several Rƒ values for the same mixture of compound. A solvent in chromatography is the liquid the paper is placed in, Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a technique because it is relatively quick. Separations in paper chromatography involve the same principles as those in thin layer chromatography, in paper chromatography, substances are distributed between a stationary phase and a mobile phase. The stationary phase is the water trapped between the fibers of the paper. The mobile phase is a solution that travels up the stationary phase. Components of the sample will separate readily according to how strongly they adsorb onto the stationary phase versus how readily they dissolve in the mobile phase. When a colored chemical sample is placed on a filter paper, the solvent diffuses up the paper, dissolving the various molecules in the sample according to the polarities of the molecules and the solvent. If the sample contains more than one color, that means it must have more than one kind of molecule, the unequal solubility causes the various color molecules to leave solution at different places as the solvent continues to move up the paper. The more soluble a molecule is, the higher it will migrate up the paper, if a chemical is very non-polar it will not dissolve at all in a very polar solvent. This is the same for a very polar chemical and a very non-polar solvent and it is very important to note that when using water as a solvent, the more polar the color, the higher it will rise on the paper
16.
Gas chromatography
–
Gas chromatography is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, in some situations, GC may help in identifying a compound. In preparative chromatography, GC can be used to prepare pure compounds from a mixture, in gas chromatography, the mobile phase is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen. Helium remains the most commonly used carrier gas in about 90% of instruments although hydrogen is preferred for improved separations, the stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside a piece of glass or metal tubing called a column. The instrument used to gas chromatography is called a gas chromatograph. The gaseous compounds being analyzed interact with the walls of the column and this causes each compound to elute at a different time, known as the retention time of the compound. The comparison of retention times is what gives GC its analytical usefulness, Gas chromatography is in principle similar to column chromatography, but has several notable differences. Second, the column through which the gas phase passes is located in an oven where the temperature of the gas can be controlled, finally, the concentration of a compound in the gas phase is solely a function of the vapor pressure of the gas. Gas chromatography is also similar to fractional distillation, since both processes separate the components of a mixture based on boiling point differences. However, fractional distillation is used to separate components of a mixture on a large scale. Gas chromatography is sometimes known as vapor-phase chromatography, or gas–liquid partition chromatography. These alternative names, as well as their respective abbreviations, are used in scientific literature. Strictly speaking, GLPC is the most correct terminology, and is preferred by many authors. Chromatography dates to 1903 in the work of the Russian scientist, german graduate student Fritz Prior developed solid state gas chromatography in 1947. Erika Cremer laid the groundwork, and oversaw much of Priors work, a gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. As the chemicals exit the end of the column, they are detected and identified electronically, the function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time. Other parameters that can be used to alter the order or time of retention are the gas flow rate, column length. In a GC analysis, a volume of gaseous or liquid analyte is injected into the entrance of the column
17.
High-performance liquid chromatography
–
High-performance liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pass a pressurized liquid solvent containing the mixture through a column filled with a solid adsorbent material. HPLC has been used for manufacturing, legal, research, Chromatography can be described as a mass transfer process involving adsorption. HPLC relies on pumps to pass a pressurized liquid and a sample mixture through a column filled with adsorbent, the active component of the column, the adsorbent, is typically a granular material made of solid particles, 2–50 micrometers in size. The components of the mixture are separated from each other due to their different degrees of interaction with the adsorbent particles. The pressurized liquid is typically a mixture of solvents and is referred to as a mobile phase and its composition and temperature play a major role in the separation process by influencing the interactions taking place between sample components and adsorbent. These interactions are physical in nature, such as hydrophobic, dipole–dipole and ionic, due to the small sample amount separated in analytical HPLC, typical column dimensions are 2. 1–4.6 mm diameter, and 30–250 mm length. Also HPLC columns are made with smaller sorbent particles and this gives HPLC superior resolving power when separating mixtures, which makes it a popular chromatographic technique. The schematic of an HPLC instrument typically includes a sampler, pumps, the sampler brings the sample mixture into the mobile phase stream which carries it into the column. The pumps deliver the flow and composition of the mobile phase through the column. The detector generates a signal proportional to the amount of sample component emerging from the column, a digital microprocessor and user software control the HPLC instrument and provide data analysis. Some models of pumps in a HPLC instrument can mix multiple solvents together in ratios changing in time. Various detectors are in use, such as UV/Vis, photodiode array or based on mass spectrometry. Most HPLC instruments also have an oven that allows for adjusting the temperature at which the separation is performed. The sample mixture to be separated and analyzed is introduced, in a small volume. The components of the move through the column at different velocities. The velocity of each component depends on its nature, on the nature of the stationary phase. The time at which an analyte elutes is called its retention time
18.
Sample (material)
–
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, an act of obtaining a sample is called sampling, which can be done by a person or automatically. Samples of material can be taken or provided for testing, analysis, inspection, investigation, demonstration, sometimes, sampling may be continuously ongoing. The material may be solid, liquid, gas, material of some characteristics such as gel or sputum, tissue, organisms. Even if a sample is not countable as individual items. A solid sample can come in one or a few pieces, or can be fragmented, granular. A section of a rod, wire, cord, sheeting, samples which are not a solid piece are commonly kept in a container of some sort. In the field of science, a liquid sample taken from a larger amount of liquid is sometimes called an aliquot
19.
Spectrophotometry
–
In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spectrophotometers, that can measure a light intensity as a function of its color. A spectrophotometer is commonly used for the measurement of transmittance or reflectance of solutions, transparent or opaque solids, such as polished glass, or gases. However they can also be designed to measure the diffusivity on any of the listed light ranges that cover around 200 nm -2500 nm using different controls. Within these ranges of light, calibrations are needed on the machine using standards that vary in type depending on the wavelength of the photometric determination, an example of an experiment in which spectrophotometry is used is the determination of the equilibrium constant of a solution. A certain chemical reaction within a solution may occur in a forward, at some point, this chemical reaction will reach a point of balance called an equilibrium point. In order to determine the concentrations of reactants and products at this point. The amount of light passes through the solution is indicative of the concentration of certain chemicals that do not allow light to pass through. The use of spectrophotometers spans various scientific fields, such as physics, materials science, chemistry, biochemistry and they are widely used in many industries including semiconductors, laser and optical manufacturing, printing and forensic examination, as well in laboratories for the study of chemical substances. By 1940 several spectrophotometers were available on the market, but early models could not work in the ultraviolet, arnold O. Beckman developed an improved version at the National Technical Laboratories Company, later the Beckman Instrument Company and ultimately Beckman Coulter. Models A, B, and C were developed, then the model D, all the electronics were contained within the instrument case, and it had a new hydrogen lamp with ultraviolet continuum, and a better monochromator. This instrument was produced from 1941 until 1976 with essentially the same design, nobel chemistry laureate Bruce Merrifield said it was probably the most important instrument ever developed towards the advancement of bioscience. There are two classes of devices, single beam and double beam. A double beam spectrophotometer compares the intensity between two light paths, one path containing a reference sample and the other the test sample. A single-beam spectrophotometer measures the light intensity of the beam before. Although comparison measurements from double-beam instruments are easier and more stable, single-beam instruments can have a dynamic range and are optically simpler. Additionally, some specialized instruments, such as spectrophotometers built onto microscopes or telescopes, are single-beam instruments due to practicality, historically, spectrophotometers use a monochromator containing a diffraction grating to produce the analytical spectrum. The grating can either be movable or fixed, if a single detector, such as a photomultiplier tube or photodiode is used, the grating can be scanned stepwise so that the detector can measure the light intensity at each wavelength
20.
Mass spectrometry
–
Mass spectrometry is an analytical technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio. In simpler terms, a mass spectrum measures the masses within a sample, mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a plot of the ion signal as a function of the mass-to-charge ratio, in a typical MS procedure, a sample, which may be solid, liquid, or gas, is ionized, for example by bombarding it with electrons. This may cause some of the molecules to break into charged fragments. The ions are detected by a capable of detecting charged particles. Results are displayed as spectra of the abundance of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses to the masses or through a characteristic fragmentation pattern. Goldstein called these positively charged anode rays Kanalstrahlen, the translation of this term into English is canal rays. Wien found that the charge-to-mass ratio depended on the nature of the gas in the discharge tube, thomson later improved on the work of Wien by reducing the pressure to create the mass spectrograph. The word spectrograph had become part of the international scientific vocabulary by 1884, a mass spectroscope is similar to a mass spectrograph except that the beam of ions is directed onto a phosphor screen. A mass spectroscope configuration was used in early instruments when it was desired that the effects of adjustments be quickly observed, once the instrument was properly adjusted, a photographic plate was inserted and exposed. The term mass spectroscope continued to be used though the direct illumination of a phosphor screen was replaced by indirect measurements with an oscilloscope. The use of the mass spectroscopy is now discouraged due to the possibility of confusion with light spectroscopy. Mass spectrometry is often abbreviated as mass-spec or simply as MS, modern techniques of mass spectrometry were devised by Arthur Jeffrey Dempster and F. W. Aston in 1918 and 1919 respectively. Sector mass spectrometers known as calutrons were used for separating the isotopes of uranium developed by Ernest O. Lawrence during the Manhattan Project, calutron mass spectrometers were used for uranium enrichment at the Oak Ridge, Tennessee Y-12 plant established during World War II. In 1989, half of the Nobel Prize in Physics was awarded to Hans Dehmelt, a mass spectrometer consists of three components, an ion source, a mass analyzer, and a detector. The ionizer converts a portion of the sample into ions, there is a wide variety of ionization techniques, depending on the phase of the sample and the efficiency of various ionization mechanisms for the unknown species. An extraction system removes ions from the sample, which are then targeted through the mass analyzer, the differences in masses of the fragments allows the mass analyzer to sort the ions by their mass-to-charge ratio
21.
Elution
–
In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent, as in washing of loaded ion-exchange resins to remove captured ions. In a liquid chromatography experiment, for example, an analyte is generally adsorbed, or bound to, the adsorbent, a solid phase, is a powder which is coated onto a solid support. Based on a composition, it can have varying affinities to hold onto other molecules—forming a thin film on its surface. Elution then is the process of removing analytes from the adsorbent by running a solvent, called an eluent, after the solvent molecules displace the analyte, the analyte can be carried out of the column for analysis. This is why as the phase passes out of the column. Predicting and controlling the order of elution is a key aspect of column chromatographic methods, an eluotropic series is listing of various compounds in order of eluting power for a given adsorbent. The “eluting power” of a solvent is largely a measure of how well the solvent can pull an analyte off the adsorbent to which it is attached and this often happens when the eluent adsorbs onto the stationary phase, displacing the analyte. Such series are useful for determining necessary solvents needed for chromatography of chemical compounds, normally such a series progresses from non-polar solvents, such as n-hexane, to polar solvents such as methanol or water. The order of solvents in an eluotropic series depends both on the phase as well as on the compound used to determine the order. The eluent or eluant is the portion of the mobile phase. It moves the analytes through the chromatograph, in liquid chromatography, the eluent is the liquid solvent, in gas chromatography, it is the carrier gas. The eluate is the material that emerges from the chromatograph. It specifically includes both the analytes and solutes passing through the column, while the eluent is only the carrier, the elution time of a solute is the time between the start of the separation and the time at which the solute elutes. In the same way, the volume is the volume of eluent required to cause elution. Under standard conditions for a mix of solutes in a certain technique. For instance, a mixture of amino acids may be separated by ion-exchange chromatography, under a particular set of conditions, the amino acids will elute in the same order and at the same elution volume. Chromatography Desorption Gradient elution in high performance liquid chromatography Leaching Brown, Phillis
22.
Chromatography
–
Chromatography is a laboratory technique for the separation of a mixture. The mixture is dissolved in a called the mobile phase. The various constituents of the mixture travel at different speeds, causing them to separate, the separation is based on differential partitioning between the mobile and stationary phases. Subtle differences in a partition coefficient result in differential retention on the stationary phase. Chromatography may be preparative or analytical, the purpose of preparative chromatography is to separate the components of a mixture for later use, and is thus a form of purification. Analytical chromatography is done normally with smaller amounts of material and is for establishing the presence or measuring the proportions of analytes in a mixture. The two are not mutually exclusive, Chromatography was first employed in Russia by the Italian-born scientist Mikhail Tsvet in 1900. He continued to work with chromatography in the first decade of the 20th century, primarily for the separation of plant pigments such as chlorophyll, carotenes, since these components have different colors they gave the technique its name. New types of chromatography developed during the 1930s and 1940s made the technique useful for separation processes. Since then, the technology has advanced rapidly, researchers found that the main principles of Tsvets chromatography could be applied in many different ways, resulting in the different varieties of chromatography described below. Advances are continually improving the performance of chromatography, allowing the separation of increasingly similar molecules. The analyte is the substance to be separated during chromatography and it is also normally what is needed from the mixture. Analytical chromatography is used to determine the existence and possibly also the concentration of analyte in a sample, a bonded phase is a stationary phase that is covalently bonded to the support particles or to the inside wall of the column tubing. A chromatogram is the output of the chromatograph. In the case of a separation, different peaks or patterns on the chromatogram correspond to different components of the separated mixture. Plotted on the x-axis is the time and plotted on the y-axis a signal corresponding to the response created by the analytes exiting the system. In the case of a system the signal is proportional to the concentration of the specific analyte separated. A chromatograph is equipment that enables a sophisticated separation, e. g. gas chromatographic or liquid chromatographic separation, Chromatography is a physical method of separation that distributes components to separate between two phases, one stationary, the other moving in a definite direction
23.
Column chromatography
–
Column chromatography in chemistry is a method used to purify individual chemical compounds from mixtures of compounds. It is often used for applications on scales from micrograms up to kilograms. The main advantage of column chromatography is the low cost. The latter prevents cross-contamination and stationary phase degradation due to recycling, the classical preparative chromatography column is a glass tube with a diameter from 5 mm to 50 mm and a height of 5 cm to 1 m with a tap and some kind of a filter at the bottom. Two methods are used to prepare a column, the dry method. For the wet method, a slurry is prepared of the eluent with the stationary phase powder, care must be taken to avoid air bubbles. A solution of the material is pipetted on top of the stationary phase. This layer is topped with a small layer of sand or with cotton or glass wool to protect the shape of the organic layer from the velocity of newly added eluent. Eluent is slowly passed through the column to advance the organic material, often a spherical eluent reservoir or an eluent-filled and stoppered separating funnel is put on top of the column. The individual components are retained by the stationary phase differently and separate from each other while they are running at different speeds through the column with the eluent, at the end of the column they elute one at a time. During the entire process the eluent is collected in a series of fractions. Fractions can be collected automatically by means of fraction collectors, the productivity of chromatography can be increased by running several columns at a time. In this case multi stream collectors are used, the composition of the eluent flow can be monitored and each fraction is analyzed for dissolved compounds, e. g. by analytical chromatography, UV absorption spectra, or fluorescence. Colored compounds can be seen through the wall as moving bands. The stationary phase or adsorbent in column chromatography is a solid, the most common stationary phase for column chromatography is silica gel, the next most common being alumina. Cellulose powder has often used in the past. Also possible are ion exchange chromatography, reversed-phase chromatography, affinity chromatography or expanded bed adsorption, the stationary phases are usually finely ground powders or gels and/or are microporous for an increased surface, though in EBA a fluidized bed is used. There is an important ratio between the stationary phase weight and the dry weight of the mixture that can be applied onto the column
24.
Thin-layer chromatography
–
Thin-layer chromatography is a chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of glass, plastic, or aluminium foil and this layer of adsorbent is known as the stationary phase. After the sample has been applied on the plate, a solvent or solvent mixture is drawn up the plate via capillary action, because different analytes ascend the TLC plate at different rates, separation is achieved. The mobile phase has different properties from the stationary phase, for example, with silica gel, a very polar substance, non-polar mobile phases such as heptane are used. The mobile phase may be a mixture, allowing chemists to fine-tune the bulk properties of the mobile phase, after the experiment, the spots are visualized. To quantify the results, the distance traveled by the substance being considered is divided by the distance traveled by the mobile phase. This ratio is called the retention factor or Rf, in general, a substance whose structure resembles the stationary phase will have low Rf, while one that has a similar structure to the mobile phase will have high retention factor. Retention factors are characteristic, but will change depending on the condition of the mobile. For this reason, chemists usually apply a sample of a compound to the sheet before running the experiment. Thin-layer chromatography can be used to monitor the progress of a reaction, identify compounds present in a given mixture and this method is referred to as HPTLC, or high-performance TLC. HPTLC typically uses thinner layers of stationary phase and smaller sample volumes, TLC plates are usually commercially available, with standard particle size ranges to improve reproducibility. They are prepared by mixing the adsorbent, such as gel, with a small amount of inert binder like calcium sulfate. This mixture is spread as a thick slurry on an unreactive carrier sheet, usually glass, thick aluminum foil, the resultant plate is dried and activated by heating in an oven for thirty minutes at 110 °C. The thickness of the absorbent layer is typically around 0.1 –0.25 mm for analytical purposes, the process is similar to paper chromatography with the advantage of faster runs, better separations, and the choice between different stationary phases. Because of its simplicity and speed TLC is often used for monitoring chemical reactions, plates can be labeled before or after the chromatography process using a pencil or other implement that will not interfere or react with the process. The solvent is allowed to evaporate off to prevent it from interfering with samples interactions with the mobile phase in the next step. If a non-volatile solvent was used to apply the sample, the needs to be dried in a vacuum chamber. This step is repeated to ensure there is enough analyte at the starting spot on the plate to obtain a visible result
25.
Chemical compound
–
A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can be converted to a different chemical composition by interaction with a chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AC + BD, where A, B, C, and D are each unique atoms, and AB, CD, AC, and BD are each unique compounds. A chemical element bonded to a chemical element is not a chemical compound since only one element. Examples are the diatomic hydrogen and the polyatomic molecule sulfur. Chemical compounds have a unique and defined chemical structure held together in a spatial arrangement by chemical bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms. There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Characteristic properties of compounds include that elements in a compound are present in a definite proportion, for example, the molecule of the compound water is composed of hydrogen and oxygen in a ratio of 2,1. In addition, compounds have a set of properties. The physical and chemical properties of compounds differ from those of their constituent elements, however, mixtures can be created by mechanical means alone, but a compound can be created only by a chemical reaction. Some mixtures are so combined that they have some properties similar to compounds. Other examples of compound-like mixtures include intermetallic compounds and solutions of metals in a liquid form of ammonia. Compounds may be described using formulas in various formats, for compounds that exist as molecules, the formula for the molecular unit is shown. For polymeric materials, such as minerals and many metal oxides, the elements in a chemical formula are normally listed in a specific order, called the Hill system
26.
Chromatography paper
–
Paper chromatography is an analytical method used to separate colored chemicals or substances. It is primarily used as a tool, having been replaced by other chromatography methods. A paper chromatography variant, two-dimensional chromatography involves using two solvents and rotating the paper 90° in between and this is useful for separating complex mixtures of compounds having similar polarity, for example, amino acids. The mobile phase is a solution that travels up the stationary phase, the mobile phase is generally an alcohol solvent mixture, while the stationary phase is a strip of chromatography paper, also called a chromatogram. Rƒ values are expressed as a fraction of two decimal places. If Rƒ value of a solution is zero, the remains in the stationary phase. If Rƒ value =1 then the solute has no affinity for the stationary phase, to calculate the Rƒ value, take the distance traveled by the substance divided by the distance traveled by the solvent. For example, if a compound travels 9.9 cm and the solvent front travels 12.7 cm, Rƒ value depends on temperature and the solvent used in experiment, so several solvents offer several Rƒ values for the same mixture of compound. A solvent in chromatography is the liquid the paper is placed in, Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a technique because it is relatively quick. Separations in paper chromatography involve the same principles as those in thin layer chromatography, in paper chromatography, substances are distributed between a stationary phase and a mobile phase. The stationary phase is the water trapped between the fibers of the paper. The mobile phase is a solution that travels up the stationary phase. Components of the sample will separate readily according to how strongly they adsorb onto the stationary phase versus how readily they dissolve in the mobile phase. When a colored chemical sample is placed on a filter paper, the solvent diffuses up the paper, dissolving the various molecules in the sample according to the polarities of the molecules and the solvent. If the sample contains more than one color, that means it must have more than one kind of molecule, the unequal solubility causes the various color molecules to leave solution at different places as the solvent continues to move up the paper. The more soluble a molecule is, the higher it will migrate up the paper, if a chemical is very non-polar it will not dissolve at all in a very polar solvent. This is the same for a very polar chemical and a very non-polar solvent and it is very important to note that when using water as a solvent, the more polar the color, the higher it will rise on the paper
27.
Cellulose
–
Cellulose is an organic compound with the formula n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units. Cellulose is an important structural component of the cell wall of green plants, many forms of algae. Some species of bacteria secrete it to form biofilms, Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a variety of derivative products such as cellophane. Conversion of cellulose from energy crops into biofuels such as ethanol is under investigation as an alternative fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton, some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In humans, cellulose acts as a bulking agent for feces and is often referred to as a dietary fiber. Cellulose was discovered in 1838 by the French chemist Anselme Payen, Cellulose was used to produce the first successful thermoplastic polymer, celluloid, by Hyatt Manufacturing Company in 1870. Production of rayon from cellulose began in the 1890s and cellophane was invented in 1912, hermann Staudinger determined the polymer structure of cellulose in 1920. The compound was first chemically synthesized in 1992, by Kobayashi, Cellulose has no taste, is odorless, is hydrophilic with the contact angle of 20–30 degrees, is insoluble in water and most organic solvents, is chiral and is biodegradable. It was shown to melt at 467 °C in 2016 and it can be broken down chemically into its glucose units by treating it with concentrated mineral acids at high temperature. Cellulose is derived from D-glucose units, which condense through β-glycosidic bonds and this linkage motif contrasts with that for α-glycosidic bonds present in starch and glycogen. This confers tensile strength in cell walls, where cellulose microfibrils are meshed into a polysaccharide matrix, compared to starch, cellulose is also much more crystalline. Whereas starch undergoes a crystalline to amorphous transition when heated beyond 60–70 °C in water, cellulose requires a temperature of 320 °C, several different crystalline structures of cellulose are known, corresponding to the location of hydrogen bonds between and within strands. Natural cellulose is cellulose I, with structures Iα and Iβ, Cellulose produced by bacteria and algae is enriched in Iα while cellulose of higher plants consists mainly of Iβ. Cellulose in regenerated cellulose fibers is cellulose II, the conversion of cellulose I to cellulose II is irreversible, suggesting that cellulose I is metastable and cellulose II is stable. With various chemical treatments it is possible to produce the structures cellulose III, many properties of cellulose depend on its chain length or degree of polymerization, the number of glucose units that make up one polymer molecule
28.
Chemical polarity
–
In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms, a polar molecule with two or more polar bonds must have an asymmetric geometry so that the bond dipoles do not cancel each other. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds, Polarity underlies a number of physical properties including surface tension, solubility, and melting and boiling points. Not all atoms attract electrons with the same force, the amount of pull an atom exerts on its electrons is called its electronegativity. Atoms with high electronegativities – such as fluorine, oxygen and nitrogen – exert a pull on electrons than atoms with lower electronegativities. In a bond, this leads to sharing of electrons between the atoms, as electrons will be drawn closer to the atom with the higher electronegativity. Because electrons have a charge, the unequal sharing of electrons within a bond leads to the formation of an electric dipole. Because the amount of charge separated in such dipoles is usually smaller than a charge, they are called partial charges, denoted as δ+. These symbols were introduced by Christopher Kelk Ingold and Edith Hilda Ingold in 1926, the bond dipole moment is calculated by multiplying the amount of charge separated and the distance between the charges. These dipoles within molecules can interact with dipoles in other molecules, Bonds can fall between one of two extremes – being completely nonpolar or completely polar. A completely nonpolar bond occurs when the electronegativities are identical and therefore possess a difference of zero, a completely polar bond is more correctly called an ionic bond, and occurs when the difference between electronegativities is large enough that one atom actually takes an electron from the other. The terms polar and nonpolar are usually applied to covalent bonds, to determine the polarity of a covalent bond using numerical means, the difference between the electronegativity of the atoms is used. Bond polarity is typically divided into three groups that are based on the difference in electronegativity between the two bonded atoms. He estimated that a difference of 1.7 corresponds to 50% ionic character, see also dipole § Molecular dipoles. While the molecules can be described as covalent, nonpolar covalent, or ionic. However, the properties are typical of such molecules. A molecule is composed of one or more chemical bonds between molecular orbitals of different atoms, a polar molecule has a net dipole as a result of the opposing charges from polar bonds arranged asymmetrically. Water is an example of a polar molecule since it has a positive charge on one side
29.
Adsorbent
–
Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent and this process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid, respectively. Adsorption is a process while absorption involves the whole volume of the material. The term sorption encompasses both processes, while desorption is the reverse of it, similar to surface tension, adsorption is a consequence of surface energy. In a bulk material, all the requirements of the constituent atoms of the material are filled by other atoms in the material. However, atoms on the surface of the adsorbent are not wholly surrounded by other adsorbent atoms, the exact nature of the bonding depends on the details of the species involved, but the adsorption process is generally classified as physisorption or chemisorption. It may also occur due to electrostatic attraction, pharmaceutical industry applications, which use adsorption as a means to prolong neurological exposure to specific drugs or parts thereof, are lesser known. The word adsorption was coined in 1881 by German physicist Heinrich Kayser, adsorption is usually described through isotherms, that is, the amount of adsorbate on the adsorbent as a function of its pressure or concentration at constant temperature. The quantity adsorbed is nearly always normalized by the mass of the adsorbent to allow comparison of different materials, to date,15 different isothem models were developed. The function is not adequate at very high pressure because in reality x / m has a maximum as pressure increases without bound. As the temperature increases, the k and n change to reflect the empirical observation that the quantity adsorbed rises more slowly. Irving Langmuir was the first to derive a scientifically based adsorption isotherm in 1918, the model applies to gases adsorbed on solid surfaces. It is a semi-empirical isotherm with a basis and was derived based on statistical thermodynamics. It is the most common isotherm equation to use due to its simplicity and it is based on four assumptions, All of the adsorption sites are equivalent and each site can only accommodate one molecule. The surface is energetically homogeneous and adsorbed molecules do not interact, at the maximum adsorption, only a monolayer is formed. Adsorption only occurs on localized sites on the surface, not with other adsorbates, the fourth condition is the most troublesome, as frequently more molecules will adsorb to the monolayer, this problem is addressed by the BET isotherm for relatively flat surfaces. The Langmuir isotherm is nonetheless the first choice for most models of adsorption, Langmuir suggested that adsorption takes place through this mechanism, A g + S ⇌ A S, where A is a gas molecule and S is an adsorption site. The direct and inverse rate constants are k and k−1, vmon is related to the number of adsorption sites through the ideal gas law
30.
Silica gel
–
Silica gel is a granular, vitreous, porous form of silicon dioxide made synthetically from sodium silicate. Silica gel contains a nano-porous silica micro-structure, suspended inside a liquid, most applications of silica gel require it to be dried, in which case it is called silica xerogel. For practical purposes, silica gel is often interchangeable with silica xerogel, silica xerogel is tough and hard, it is more solid than common household gels like gelatin or agar. It is a naturally occurring mineral that is purified and processed into either granular or beaded form, as a desiccant, it has an average pore size of 2.4 nanometers and has a strong affinity for water molecules. Silica gel is most commonly encountered in life as beads in a small paper packet. In this form, it is used as a desiccant to control humidity to avoid spoilage or degradation of some goods. Because silica gel can have added chemical indicators and absorbs moisture very well, silica gel was in existence as early as the 1640s as a scientific curiosity. It was used in World War I for the adsorption of vapors, the synthetic route for producing silica gel was patented by chemistry professor Walter A. Patrick at Johns Hopkins University in 1918. Type A - clear pellets, approximate pore diameter,2.5 nm, drying and moistureproof properties, can be used as catalyst carriers, adsorbents, separators and variable-pressure adsorbent. Type B - translucent white pellets, pore diameter,4. 5-7.0 nm, liquid adsorbents, drier and perfume carriers, also may be used as catalyst carriers, type C - translucent, micro-pored structure, raw material for preparation of silica gel cat litter. Additionally dried and screened, it forms macro-pored silica gel which is used as drier, adsorbent, silica alumina gel - light yellow, chemically stable, flame-resistant, insoluble except in alkali or hydrofluoric acid. Superficial polarity, thermal stability, performance greater than fine-pored silica gel, silica gels high specific surface area allows it to adsorb water readily, making it useful as a desiccant. Silica gel is often described as absorbing moisture, which may be appropriate when the gels microscopic structure is ignored, however, material silica gel removes moisture by adsorption onto the surface of its numerous pores rather than by absorption into the bulk of the gel. Once saturated with water, the gel can be regenerated by heating it to 120 °C for 1–2 hours, some types of silica gel will pop when exposed to enough water. This is caused by breakage of the silica spheres when contacting the water, an aqueous solution of sodium silicate is acidified to produce a gelatinous precipitate that is washed, then dehydrated to produce colorless silica gel. When a visible indication of the content of the silica gel is required. This will cause the gel to be blue when dry and pink when hydrated, an alternative indicator is methyl violet which is orange when dry and green when hydrated. Due to the connection between cancer and cobalt chloride, it has been forbidden in Europe on silica gel, in many items, moisture encourages the growth of mold and spoilage
31.
Aluminium oxide
–
Aluminium oxide or aluminum oxide is a chemical compound of aluminium and oxygen with the chemical formula Al2O3. It is the most commonly occurring of several aluminium oxides, and it is commonly called alumina, and may also be called aloxide, aloxite, or alundum depending on particular forms or applications. It occurs naturally in its crystalline polymorphic phase α-Al2O3 as the mineral corundum, varieties of form the precious gemstones ruby. Al2O3 is significant in its use to produce metal, as an abrasive owing to its hardness. Corundum is the most common naturally occurring form of aluminium oxide. Rubies and sapphires are gem-quality forms of corundum, which owe their characteristic colors to trace impurities, rubies are given their characteristic deep red color and their laser qualities by traces of chromium. Sapphires come in different colors given by various other impurities, such as iron, Al2O3 is an electrical insulator but has a relatively high thermal conductivity for a ceramic material. Aluminium oxide is insoluble in water, in its most commonly occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools. Aluminium oxide is responsible for the resistance of aluminium to weathering. Metallic aluminium is very reactive with oxygen, and a thin passivation layer of aluminium oxide forms on any exposed aluminium surface. This layer protects the metal from further oxidation, the thickness and properties of this oxide layer can be enhanced using a process called anodising. A number of alloys, such as bronzes, exploit this property by including a proportion of aluminium in the alloy to enhance corrosion resistance. Aluminium oxide was taken off the United States Environmental Protection Agencys chemicals lists in 1988, aluminium oxide is on EPAs Toxics Release Inventory list if it is a fibrous form. Al2O3 +6 HF →2 AlF3 +3 H2O Al2O3 +2 NaOH +3 H2O →2 NaAl4 The most common form of aluminium oxide is known as corundum. The oxygen ions form a hexagonal close-packed structure with aluminium ions filling two-thirds of the octahedral interstices. In terms of its crystallography, corundum adopts a trigonal Bravais lattice with a group of R-3c. The primitive cell contains two units of aluminium oxide. Each has a crystal structure and properties
32.
High-performance thin-layer chromatography
–
High performance thin layer chromatography is an enhanced form of thin layer chromatography. Automation is useful to overcome the uncertainty in droplet size and position when the sample is applied to the TLC plate by hand, one recent approach to automation has been the use of piezoelectric devices and inkjet printers for applying the sample. The spot capacity can be increased by developing the plate with two different solvents, using two-dimensional chromatography, the procedure begins with development of sample loaded plate with first solvent. After removing it, the plate is rotated 90° and developed with a second solvent, widely used instrument for HPTLC is from CAMAG, Switzerland. It provides automated sample application, plate development, detection and documentation, notes Sources Puri, A. Ahmad, A. and Panda, B. P. Development of an HPTLC-based diagnostic method for invasive aspergillosis, doi,10. 1002/bmc.1382 Ajaz Ahmad, M Mujeeb, Bibhu Prasad Panda An HPTLC Method for the Simultaneous Analysis of Compactin and Citrinin in Penicillium citrinum Fermentation Broth. Journal of Planar Chromatography-modern TLC23, 282–285
33.
Displacement chromatography
–
The result is that the components are resolved into consecutive “rectangular” zones of highly concentrated pure substances rather than solvent-separated “peaks”. It is primarily a technique, higher product concentration, higher purity. The advent of displacement chromatography can be attributed to Arne Tiselius, who in 1943 first classified the modes of chromatography as frontal, elution, displacement chromatography found a variety of applications including isolation of transuranic elements and biochemical entities. The technique was redeveloped by Csaba Horváth, who employed modern high-pressure columns and it has since found many applications, particularly in the realm of biological macromolecule purification. As in any chromatography, equilibrium is established between molecules of a given kind bound to the matrix and those of the same kind free in solution. Because the number of binding sites is finite, when the concentration of free in solution is large relative to the dissociation constant for the sites. This results in a downward-curvature in the plot of bound vs free solute, a molecule with a high affinity for the matrix will compete more effectively for binding sites, leaving the mobile phase enriched in the lower-affinity solute. At the beginning of the run, a mixture of solutes to be separated is applied to the column, the higher-affinity solutes are preferentially retained near the head of the column, with the lower-affinity solutes moving farther downstream. The fastest moving component begins to form a pure zone downstream, the other components also begin to form zones, but the continued supply of the mixed feed at head of the column prevents full resolution. After the entire sample is loaded, the feed is switched to the displacer, the displacer forms a sharp-edged zone at the head of the column, pushing the other components downstream. The size and loading of the column are chosen to let this sorting process reach completion before the components reach the bottom of the column. The solutes appear at the bottom of the column as a series of zones, each consisting of one purified component. After the last solute has been eluted, it is necessary to strip the displacer from the column, since the displacer was chosen for high affinity, this can pose a challenge. On reverse-phase materials, a wash with a percentage of organic solvent may suffice. Large pH shifts are often employed. For gel-type ion exchangers, selectivity reversal at high ionic strength can also provide a solution. Sometimes the displacer is specifically designed with a functional group to shift its affinity. After the displacer is washed out, the column is washed as needed to restore it to its state for the next run
34.
Analytical chemistry
–
Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter. In practice separation, identification or quantification may constitute the entire analysis or be combined with another method, qualitative analysis identifies analytes, while quantitative analysis determines the numerical amount or concentration. Analytical chemistry consists of classical, wet chemical methods and modern, classical qualitative methods use separations such as precipitation, extraction, and distillation. Identification may be based on differences in color, odor, melting point, boiling point, classical quantitative analysis uses mass or volume changes to quantify amount. Instrumental methods may be used to separate samples using chromatography, electrophoresis or field flow fractionation, then qualitative and quantitative analysis can be performed, often with the same instrument and may use light interaction, heat interaction, electric fields or magnetic fields. Often the same instrument can separate, identify and quantify an analyte, Analytical chemistry is also focused on improvements in experimental design, chemometrics, and the creation of new measurement tools. Analytical chemistry has applications to forensics, medicine, science. Analytical chemistry has been important since the days of chemistry, providing methods for determining which elements. The first instrumental analysis was flame emissive spectrometry developed by Robert Bunsen, most of the major developments in analytical chemistry take place after 1900. During this period instrumental analysis becomes progressively dominant in the field, in particular many of the basic spectroscopic and spectrometric techniques were discovered in the early 20th century and refined in the late 20th century. The separation sciences follow a similar line of development and also become increasingly transformed into high performance instruments. In the 1970s many of these began to be used together as hybrid techniques to achieve a complete characterization of samples. Lasers have been used in chemistry as probes and even to initiate. Modern analytical chemistry is dominated by instrumental analysis, many analytical chemists focus on a single type of instrument. Academics tend to focus on new applications and discoveries or on new methods of analysis. The discovery of a present in blood that increases the risk of cancer would be a discovery that an analytical chemist might be involved in. An effort to develop a new method might involve the use of a laser to increase the specificity and sensitivity of a spectrometric method. Many methods, once developed, are kept purposely static so that data can be compared over long periods of time and this is particularly true in industrial quality assurance, forensic and environmental applications
35.
Biochemistry
–
Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of energy through metabolism. Biochemistry is closely related to biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate. The chemistry of the cell depends on the reactions of smaller molecules. These can be inorganic, for water and metal ions, or organic, for example the amino acids. The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism, the findings of biochemistry are applied primarily in medicine, nutrition, and agriculture. In medicine, biochemists investigate the causes and cures of diseases, in nutrition, they study how to maintain health and study the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control. However, biochemistry as a scientific discipline has its beginning sometime in the 19th century, or a little earlier. Gowland Hopkins on enzymes and the nature of biochemistry. The term biochemistry itself is derived from a combination of biology, the German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea and these techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Another significant historic event in biochemistry is the discovery of the gene and this part of biochemistry is often called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, in 1958, George Beadle and Edward Tatum received the Nobel Prize for work in fungi showing that one gene produces one enzyme. In 1988, Colin Pitchfork was the first person convicted of murder with DNA evidence, mello received the 2006 Nobel Prize for discovering the role of RNA interference, in the silencing of gene expression. Around two dozen of the 92 naturally occurring elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life, while a few common ones are not used, most organisms share element needs, but there are a few differences between plants and animals
36.
Petrochemical
–
Petrochemicals, also called petroleum distillates, are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from fossil fuels, such as coal or natural gas. The two most common classes are olefins and aromatics. Oil refineries produce olefins and aromatics by fluid catalytic cracking of petroleum fractions, chemical plants produce olefins by steam cracking of natural gas liquids like ethane and propane. Aromatics are produced by catalytic reforming of naphtha, Olefins and aromatics are the building-blocks for a wide range of materials such as solvents, detergents, and adhesives. Olefins are the basis for polymers and oligomers used in plastics, resins, fibers, elastomers, lubricants, global ethylene and propylene production are about 115 million tonnes and 70 million tonnes per annum, respectively. Aromatics production is approximately 70 million tonnes, the largest petrochemical industries are located in the USA and Western Europe, however, major growth in new production capacity is in the Middle East and Asia. There is substantial inter-regional petrochemical trade, primary petrochemicals are divided into three groups depending on their chemical structure, Olefins includes ethylene, propylene, and butadiene. Ethylene and propylene are important sources of chemicals and plastics products. Butadiene is used in making synthetic rubber, aromatics includes benzene, toluene, and xylenes. Benzene is a raw material for dyes and synthetic detergents, manufacturers use xylenes to produce plastics and synthetic fibers. Synthesis gas is a mixture of carbon monoxide and hydrogen used to make ammonia, ammonia is used to make the fertilizer urea and methanol is used as a solvent and chemical intermediate. The prefix petro- is an abbreviation of the word petroleum, since petro- is Ancient Greek for rock. Therefore, the correct term would be oleochemicals. However, the term oleochemical is used to describe chemicals derived from plant, benzene, toluene and xylenes, as a whole referred to as BTX and primarily obtained from petroleum refineries by extraction from the reformate produced in catalytic reformers. Methane and BTX are used directly as feedstocks for producing petrochemicals, the output ethylene capacity of large steam crackers ranged up to as much as 1.0 –1.5 Mt per year. Steam crackers are not to be confused with steam reforming plants used to produce hydrogen, like commodity chemicals, petrochemicals are made on a very large scale. Petrochemical manufacturing units differ from commodity chemical plants in that often produce a number of related products
37.
Environmental monitoring
–
Environmental monitoring describes the processes and activities that need to take place to characterise and monitor the quality of the environment. All monitoring strategies and programmes have reasons and justifications which are designed to establish the current status of an environment or to establish trends in environmental parameters. In all cases the results of monitoring will be reviewed, analysed statistically, the design of a monitoring programme must therefore have regard to the final use of the data before monitoring starts. Air quality monitoring is performed using specialized equipment and analytical methods used to establish air pollutant concentrations, air monitors are operated by citizens, regulatory agencies, and researchers to investigate air quality and the effects of air pollution. Air dispersion models that combine topographic, emissions and meteorological data to predict air pollutant concentrations are often helpful in interpreting air monitoring data. If an air monitor produces concentrations of chemical compounds, a unique chemical fingerprint of a particular air pollution source may emerge from analysis of the data. Soil monitoring is the process of collection of soil and testing in laboratory by analytical methods, in laboratory, soil can be tested for pH, Chlorides, Sulphates, Phosphates and other metals. Water quality monitoring is of use without a clear and unambiguous definition of the reasons for the monitoring. Almost all monitoring is in some part invasive of the environment under study and extensive and this may be a critical consideration in wilderness areas or when monitoring very rare organisms or those that are averse to human presence. Unless individual monitoring projects fit into a strategic framework, the results are unlikely to be published. The list can be expanded or reduced based on developing knowledge, freshwater environments have been extensively studied for many years and there is a robust understanding of the interactions between chemistry and the environment across much of the world. However, as new materials are developed and new pressures come to bear, in the last 20 years acid rain, synthetic hormone analogues, halogenated hydrocarbons, greenhouse gases and many others have required changes to monitoring strategies. In ecological monitoring, the strategy and effort is directed at the plants. However, in more generalised environmental monitoring, many act as robust indicators of the quality of the environment that they are experiencing or have experienced in the recent past. The steep decline in fish populations was one of the early indications of the problem that later became known as acid rain. In recent years much more attention has been given to a holistic approach in which the ecosystem health is assessed and used as the monitoring tool itself. It is this approach that underpins the monitoring protocols of the Water Framework Directive in the European Union, the ‘measurement’ of dose often means the measurement of a dose equivalent quantity as a proxy for a dose quantity that cannot be measured directly. Also, sampling may be involved as a step to measurement of the content of radionuclides in environmental media.8
38.
Environmental remediation
–
Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water. This would mean that once requested by the government or a land remediation authority, immediate action should be taken as this can impact negatively on human health, to help with environmental remediation, one can get environmental remediation services. These services help eliminate radiation sources in order to protect the environment. </ref> In the United States, the most comprehensive set of Preliminary Remediation Goals is from the Environmental Protection Agency Region 9, a set of standards used in Europe exists and is often called the Dutch standards. The European Union is rapidly moving towards Europe-wide standards, although most of the nations in Europe have their own standards at present. Once a site is suspected of being contaminated there is a need to assess the contamination, often the assessment begins with preparation of a Phase I Environmental Site Assessment. The historical use of the site and the used and produced on site will guide the assessment strategy and type of sampling. Often nearby sites owned by the company or which are nearby and have been reclaimed, levelled or filled are also contaminated even where the current land use seems innocuous. For example, a car park may have been levelled by using contaminated waste in the fill, also important is to consider off site contamination of nearby sites often through decades of emissions to soil, groundwater, and air. Ceiling dust, topsoil, surface and groundwater of nearby properties should also be tested, in the US there has been a mechanism for taxing polluting industries to form a Superfund to remediate abandoned sites, or to litigate to force corporations to remediate their contaminated sites. There are several tools for mapping these sites and which allow the user to view additional information, Remediation technologies are many and varied but can generally be categorized into ex-situ and in-situ methods. Ex-situ methods involve excavation of affected soils and subsequent treatment at the surface as well as extraction of contaminated groundwater, in-situ methods seek to treat the contamination without removing the soils or groundwater. Various technologies have developed for remediation of oil-contaminated soil/sediments. Traditional remediation approaches consist of soil excavation and disposal to landfill and groundwater pump, thermal desorption is a technology for soil remediation. During the process a desorber volatilizes the contaminants to separate them from especially soil or sludge, after that the contaminants can either be collected or destroyed in an offgas treatment system. Excavation processes can be as simple as hauling the contaminated soil to a regulated landfill, recent advancements in bioaugmentation and biostimulation of the excavated material have also proven to be able to remediate semi-volatile organic compounds onsite. If the contamination affects a river or bay bottom, then dredging of bay mud or other silty clays containing contaminants may be conducted, recently, ExSitu Chemical oxidation has also been utilized in the remediation of contaminated soil. This process involves the excavation of the area into large bermed areas where they are treated using chemical oxidation methods
39.
Chemical industry
–
The chemical industry comprises the companies that produce industrial chemicals. Central to the world economy, it converts raw materials into more than 70,000 different products. The plastics industry contains some overlap, as most chemical companies produce plastic as well as other chemicals, although chemicals were made and used throughout history, the birth of the heavy chemical industry coincided with the beginnings of the Industrial Revolution in general. One of the first chemicals to be produced in large amounts through industrial process was sulfuric acid, in 1736, the pharmacist Joshua Ward developed a process for its production that involved heating saltpeter, allowing the sulfur to oxidize and combine with water. It was the first practical production of acid on a large scale. John Roebuck and Samuel Garbett were the first to establish a factory in Prestonpans, Scotland, in 1749. In the early 18th century, cloth was bleached by treating it with urine or sour milk and exposing it to sunlight for long periods of time. His powder was made by reacting chlorine with dry slaked lime and proved to be a cheap and he opened a factory in St Rollox, north of Glasgow, and production went from just 52 tons in 1799 to almost 10,000 tons just five years later. Soda ash was used since ancient times in the production of glass, textile, soap, and paper, and the source of the potash had traditionally been wood ashes in Western Europe. By the 18th century, this source was becoming uneconomical due to deforestation, the Leblanc process was patented in 1791 by Nicolas Leblanc who then built a Leblanc plant at Saint-Denis. He was denied his prize money because of the French Revolution, however, it was in Britain that the Leblanc process really took off. William Losh built the first soda works in Britain at the Losh, Wilson and Bell works on the River Tyne in 1816, when these tariffs were repealed, the British soda industry was able to rapidly expand. James Muspratts chemical works in Liverpool and Charles Tennants complex near Glasgow became the largest chemical production centres anywhere, by the 1870s, the British soda output of 200,000 tons annually exceeded that of all other nations in the world combined. These huge factories began to produce a diversity of chemicals as the Industrial Revolution matured. Originally, large quantities of waste were vented into the environment from the production of soda. This provided for inspection of the factories and imposed heavy fines on those exceeding the limits on pollution. Methods were soon devised to make useful byproducts from the alkali, the Solvay process was developed by the Belgian industrial chemist Ernest Solvay in 1861. In 1864, Solvay and his brother Alfred constructed a plant in the Belgian town of Charleroi and in 1874, they expanded into a plant in Nancy
40.
Affinity chromatography
–
Biological macromolecules such as enzymes and other proteins, interact with other molecules with high specificity through several different types of bonds and interaction. Such interactions including hydrogen bonding, ionic interaction, disulfide bridges, hydrophobic interaction, the stationary phase is typically a gel matrix, often of agarose, a linear sugar molecule derived from algae. Usually the starting point is a heterogeneous group of molecules in solution, such as a cell lysate. The molecule of interest will have a known and defined property. The process itself can be thought of as an entrapment, with the target molecule becoming trapped on a solid or stationary phase or medium, the other molecules in the mobile phase will not become trapped as they do not possess this property. The stationary phase can then be removed from the mixture, washed, possibly the most common use of affinity chromatography is for the purification of recombinant proteins. These steps are usually done at ambient pressure, a third method, expanded bed absorption, which combines the advantages of the two methods mentioned above, has also been developed. The solid phase particles are placed in a column where liquid phase is pumped in from the bottom, the gravity of the particles ensure that the solid phase does not exit the column with the liquid phase. Affinity columns can be eluted by changing salt concentrations, pH, pI, charge, more recently, setups employing more than one column in series have been developed. The advantage compared to single column setups is that the material can be fully loaded. The resin costs per amount of produced product can thus be drastically reduced, since one column can always be eluted and regenerated while the other column is loaded, already two columns are sufficient to make full use of the advantages. Additional columns can give additional flexibility for elution and regeneration times, at the cost of additional equipment, Affinity chromatography can be used in a number of applications, including nucleic acid purification, protein purification from cell free extracts, and purification from blood. Many different affinity media exist for a variety of possible uses, briefly, they are, Activated/Functionalized – Works as a functional spacer, support matrix, and eliminates handling of toxic reagents. Amino Acid – Used with a variety of proteins, proteins, peptides. Avidin Biotin – Used in the process of biotin/avidin and their derivatives. Carbohydrate Bonding – Most often used with glycoproteins or any other carbohydrate-containing substance, carbohydrate – Used with lectins, glycoproteins, or any other carbohydrate metabolite protein. Dye Ligand – This media is nonspecific, but mimics biological substrates, glutathione – Useful for separation of GST tagged recombinant proteins. Heparin – This media is an affinity ligand, and it is most useful for separation of plasma coagulation proteins
