Fluorescence spectroscopy is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light. A complementary technique is absorption spectroscopy. In the special case of single molecule fluorescence spectroscopy, intensity fluctuations from the emitted light are measured from either single fluorophores, or pairs of fluorophores. Devices that measure fluorescence are called fluorometers. Molecules have various states referred to as energy levels. Fluorescence spectroscopy is concerned with electronic and vibrational states; the species being examined has a ground electronic state of interest, an excited electronic state of higher energy. Within each of these electronic states there are various vibrational states. In fluorescence, the species is first excited, by absorbing a photon, from its ground electronic state to one of the various vibrational states in the excited electronic state.
Collisions with other molecules cause the excited molecule to lose vibrational energy until it reaches the lowest vibrational state of the excited electronic state. This process is visualized with a Jablonski diagram; the molecule drops down to one of the various vibrational levels of the ground electronic state again, emitting a photon in the process. As molecules may drop down into any of several vibrational levels in the ground state, the emitted photons will have different energies, thus frequencies. Therefore, by analysing the different frequencies of light emitted in fluorescent spectroscopy, along with their relative intensities, the structure of the different vibrational levels can be determined. For atomic species, the process is similar; this process of re-emitting the absorbed photon is "resonance fluorescence" and while it is characteristic of atomic fluorescence, is seen in molecular fluorescence as well. In a typical fluorescence measurement, the excitation wavelength is fixed and the detection wavelength varies, while in a fluorescence excitation measurement the detection wavelength is fixed and the excitation wavelength is varied across a region of interest.
An emission map is measured by recording the emission spectra resulting from a range of excitation wavelengths and combining them all together. This is a three dimensional surface data set: emission intensity as a function of excitation and emission wavelengths, is depicted as a contour map. Two general types of instruments exist: filter fluorometers that use filters to isolate the incident light and fluorescent light and spectrofluorometers that use a diffraction grating monochromators to isolate the incident light and fluorescent light. Both types use the following scheme: the light from an excitation source passes through a filter or monochromator, strikes the sample. A proportion of the incident light is absorbed by the sample, some of the molecules in the sample fluoresce; the fluorescent light is emitted in all directions. Some of this fluorescent light passes through a second filter or monochromator and reaches a detector, placed at 90° to the incident light beam to minimize the risk of transmitted or reflected incident light reaching the detector.
Various light sources may be used as excitation sources, including lasers, LED, lamps. A laser only emits light of high irradiance at a narrow wavelength interval under 0.01 nm, which makes an excitation monochromator or filter unnecessary. The disadvantage of this method is. A mercury vapor lamp is a line lamp. By contrast, a xenon arc has a continuous emission spectrum with nearly constant intensity in the range from 300-800 nm and a sufficient irradiance for measurements down to just above 200 nm. Filters and/or monochromators may be used in fluorimeters. A monochromator transmits light of an adjustable wavelength with an adjustable tolerance; the most common type of monochromator utilizes a diffraction grating, that is, collimated light illuminates a grating and exits with a different angle depending on the wavelength. The monochromator can be adjusted to select which wavelengths to transmit. For allowing anisotropy measurements, the addition of two polarization filters is necessary: One after the excitation monochromator or filter, one before the emission monochromator or filter.
As mentioned before, the fluorescence is most measured at a 90° angle relative to the excitation light. This geometry is used instead of placing the sensor at the line of the excitation light at a 180° angle in order to avoid interference of the transmitted excitation light. No monochromator is perfect and it will transmit some stray light, that is, light with other wavelengths than the targeted. An ideal monochromator would only transmit light in the specified range and have a high wavelength-independent transmission; when measuring at a 90° angle, only the light scattered by the sample causes stray light. This results in a better signal-to-noise ratio, lowers the detection limit by a factor 10000, when compared to the 180° geometry. Furthermore, the fluorescence can be measured from the front, done for turbid or opaque samples; the detector can either be multichanneled. The single-channeled detector can only detect the intensity of one wavelength
Fused quartz or fused silica is glass consisting of silica in amorphous form. It differs from traditional glasses in containing no other ingredients, which are added to glass to lower the melt temperature. Fused silica, has high working and melting temperatures. Although the terms fused quartz and fused silica are used interchangeably, the optical and thermal properties of fused silica are superior to those of fused quartz and other types of glass due to its purity. For these reasons, it finds use in situations such as semiconductor fabrication and laboratory equipment, it transmits ultraviolet better than other glasses, so is used to make lenses and optics for the ultraviolet spectrum. The low coefficient of thermal expansion of fused quartz makes it a useful material for precision mirror substrates. Fused quartz is produced by fusing high-purity silica sand. There are four basic types of commercial silica glass: Type I is produced by induction melting natural quartz in a vacuum or an inert atmosphere.
Type II is produced by fusing quartz crystal powder in a high-temperature flame. Type III is produced by burning SiCl4 in a hydrogen-oxygen flame. Type IV is produced by burning SiCl4 in a water vapor-free plasma flame. Quartz contains only silicon and oxygen, although commercial quartz glass contains impurities; the most dominant impurities are titanium. Melting is effected at 1650°C using either an electrically heated furnace or a gas/oxygen-fuelled furnace. Fused silica can be made from any silicon-rich chemical precursor using a continuous process which involves flame oxidation of volatile silicon compounds to silicon dioxide, thermal fusion of the resulting dust; this results in a transparent glass with an ultra-high purity and improved optical transmission in the deep ultraviolet. One common method involves adding silicon tetrachloride to a hydrogen–oxygen flame, but this precursor results in environmentally unfriendly byproducts including chlorine and hydrochloric acid. Fused quartz is transparent.
The material can, become translucent if small air bubbles are allowed to be trapped within. The water content is determined by the manufacturing process. Flame-fused material always has a higher water content due to the combination of the hydrocarbons and oxygen fuelling the furnace, forming hydroxyl groups within the material. An IR grade material has an content of <10 parts per million. Most of the applications of fused silica exploit its wide transparency range, which extends from the UV to the near IR. Fused silica is the key starting material for optical fiber, used for telecommunications; because of its strength and high melting point, fused silica is used as an envelope for halogen lamps and high-intensity discharge lamps, which must operate at a high envelope temperature to achieve their combination of high brightness and long life. Vacuum tubes with silica envelopes allowed for radiation cooling by incandescent anodes; because of its strength, fused silica was used in deep diving vessels such as the bathysphere and benthoscope.
Fused silica is used to form the windows of manned spacecraft, including the Space Shuttle and International Space Station. The combination of strength, thermal stability, UV transparency makes it an excellent substrate for projection masks for photolithography, its UV transparency finds uses in the semiconductor industry. EPROMs are recognizable by the transparent fused quartz window which sits on top of the package, through which the silicon chip is visible, which permits exposure to UV light during erasing. Due to the thermal stability and composition, it is used in semiconductor fabrication furnaces. Fused quartz has nearly ideal properties for fabricating first surface mirrors such as those used in telescopes; the material behaves in a predictable way and allows the optical fabricator to put a smooth polish onto the surface and produce the desired figure with fewer testing iterations. In some instances, a high-purity UV grade of fused quartz has been used to make several of the individual uncoated lens elements of special-purpose lenses including the Zeiss 105mm f/4.3 UV Sonnar, a lens made for the Hasselblad camera, the Nikon UV-Nikkor 105mm f/4.5 lens.
These lenses are used for UV photography, as the quartz glass has a lower extinction rate than lenses made with more common flint or crown glass formulas. Fused quartz can be metallised and etched for use as a substrate for high-precision microwave circuits, the thermal stability making it a good choice for narrowband filters and similar demanding applications; the lower dielectric constant than alumina allows thinner substrates. Fused quartz is the material used for modern glass instruments such as the glass harp and the verrophone, is used for new builds of the historical glass harmonica. Here, the superior strength and structure of fused quartz gives it a greater dynamic range and a clearer sound than the used lead crystal. Fused silica as an industrial raw material is used to make various refractory shapes such as crucibles, trays and rollers for many high-temperature thermal processes including steelmaking, investment casting, glass manufacture. Refractory shapes made from fused silica hav
In analytical chemistry, a calibration curve known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. A calibration curve is one approach to the problem of instrument calibration; the calibration curve is a plot of how the instrumental response, the so-called analytical signal, changes with the concentration of the analyte. The operator prepares a series of standards across a range of concentrations near the expected concentration of analyte in the unknown; the concentrations of the standards must lie within the working range of the technique they are using. Analyzing each of these standards using the chosen technique will produce a series of measurements. For most analyses a plot of instrument response vs. concentration will show a linear relationship. The operator can measure the response of the unknown and, using the calibration curve, can interpolate to find the concentration of analyte.
In more general use, a calibration curve is a curve or table for a measuring instrument which measures some parameter indirectly, giving values for the desired quantity as a function of values of sensor output. For example, a calibration curve can be made for a particular pressure transducer to determine applied pressure from transducer output; such a curve is used when an instrument uses a sensor whose calibration varies from one sample to another, or changes with time or use. The data - the concentrations of the analyte and the instrument response for each standard - can be fit to a straight line, using linear regression analysis; this yields a model described by the equation y = mx + y0, where y is the instrument response, m represents the sensitivity, y0 is a constant that describes the background. The analyte concentration of unknown samples may be calculated from this equation. Many different variables can be used as the analytical signal. For instance, chromium might be measured using a chemiluminescence method, in an instrument that contains a photomultiplier tube as the detector.
The detector converts the light produced by the sample into a voltage, which increases with intensity of light. The amount of light measured is the analytical signal. Most analytical techniques use a calibration curve. There are a number of advantages to this approach. First, the calibration curve provides a reliable way to calculate the uncertainty of the concentration calculated from the calibration curve. Second, the calibration curve provides data on an empirical relationship; the mechanism for the instrument's response to the analyte may be predicted or understood according to some theoretical model, but most such models have limited value for real samples. Many theoretical relationships, such as fluorescence, require the determination of an instrumental constant anyway, by analysis of one or more reference standards; the calibration curve for a particular analyte in a particular sample provides the empirical relationship needed for those particular measurements. The chief disadvantages are that the standards require a supply of the analyte material, preferably of high purity and in known concentration, that the standards and the unknown are in the same matrix.
Some analytes - e.g. particular proteins - are difficult to obtain pure in sufficient quantity. Other analytes are in complex matrices, e.g. heavy metals in pond water. In this case, the matrix may attenuate the signal of the analyte. Therefore, a comparison between the standards and the unknown is not possible; the method of standard addition is a way to handle such a situation. As expected, the concentration of the unknown will have some error which can be calculated from the formula below; this formula assumes. It is important to note that the error in the concentration will be minimal if the signal from the unknown lies in the middle of the signals of all the standards s x = s y | m | 1 n + 1 k + 2 m 2 ∑ 2
In chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. It is more specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, near-infrared, but does not cover time-resolved spectroscopic techniques. Spectrophotometry is a tool that hinges on the quantitative analysis of molecules depending on how much light is absorbed by colored compounds. Spectrophotometry uses photometers, known as spectrophotometers, that can measure a light beam's intensity as a function of its color. Important features of spectrophotometers are spectral bandwidth, the percentage of sample-transmission, the logarithmic range of sample-absorption, sometimes a percentage of reflectance measurement. A spectrophotometer is used for the measurement of transmittance or reflectance of solutions, transparent or opaque solids, such as polished glass, or gases. Although many biochemicals are colored, as in, they absorb visible light and therefore can be measured by colorimetric procedures colorless biochemicals can be converted to colored compounds suitable for chromogenic color-forming reactions to yield compounds suitable for colorimetric analysis.
However, they can be designed to measure the diffusivity on any of the listed light ranges that cover around 200 nm - 2500 nm using different controls and calibrations. 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 and reverse direction, where reactants form products and products break down into reactants. At some point, this chemical reaction will reach a point of balance called an equilibrium point. In order to determine the respective concentrations of reactants and products at this point, the light transmittance of the solution can be tested using spectrophotometry; the amount of light that passes through the solution is indicative of the concentration of certain chemicals that do not allow light to pass through.
The absorption of light is due to the interaction of light with the electronic and vibrational modes of molecules. Each type of molecule has an individual set of energy levels associated with the makeup of its chemical bonds and nuclei, thus will absorb light of specific wavelengths, or energies, resulting in unique spectral properties; this is based upon its distinct makeup. The use of spectrophotometers spans various scientific fields, such as physics, materials science, biochemistry,Chemical Engineering, molecular biology, they are used in many industries including semiconductors and optical manufacturing and forensic examination, as well in laboratories for the study of chemical substances. Spectrophotometry is used in measurements of enzyme activities, determinations of protein concentrations, determinations of enzymatic kinetic constants, measurements of ligand binding reactions. A spectrophotometer is able to determine, depending on the control or calibration, what substances are present in a target and how much through calculations of observed wavelengths.
In astronomy, the term spectrophotometry refers to the measurement of the spectrum of a celestial object in which the flux scale of the spectrum is calibrated as a function of wavelength by comparison with an observation of a spectrophotometric standard star, corrected for the absorption of light by the Earth's atmosphere. Invented by Arnold O. Beckman in 1940, the spectrophotometer was created with the aid of his colleagues at his company National Technical Laboratories founded in 1935 which would become Beckman Instrument Company and Beckman Coulter; this would come as a solution to the created spectrophotometers which were unable to absorb the ultraviolet correctly. He would start with the invention of Model A, it would be found that this did not give satisfactory results, therefore in Model B, there was a shift from a glass to a quartz prism which allowed for better absorbance results. From there, Model C was born with an adjustment to the wavelength resolution which ended up having three units of it produced.
The last and most popular model became Model D, better recognized now as the DU spectrophotometer which contained the instrument case, hydrogen lamp with ultraviolent continuum and a better monochromator. It was produced from 1941 to 1976 where the price for it in 1941 was US$723. In the words of Nobel chemistry laureate Bruce Merrifield, it was "probably the most important instrument developed towards the advancement of bioscience."Once it became discontinued in 1976, another company known as Hewlett-Packard created the first commercially available diode-assay spectrophotometer in 1979 known as the HP 8450A. Diode-assay spectrophotometers differed from the original spectrophotometer created by Beckman because it was the first single-beam microprocessor-controlled spectrophotometer that scanned multiple wavelengths at a time in seconds, it irradiates the sample with polychromatic light which the sample absorbs depending on its properties. It is transmitted back by grating the photodiode array which detects the wavelength region of the spectrum.
Since the creation and implementation of spectrophotometry devices has increased immensely and has become one of the mos
Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral; the transformation from α-quartz to β-quartz takes place abruptly at 573 °C. Since the transformation is accompanied by a significant change in volume, it can induce fracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz. Since antiquity, varieties of quartz have been the most used minerals in the making of jewelry and hardstone carvings in Eurasia; the word "quartz" is derived from the German word "Quarz", which had the same form in the first half of the 14th century in Middle High German in East Central German and which came from the Polish dialect term kwardy, which corresponds to the Czech term tvrdý.
The Ancient Greeks referred to quartz as κρύσταλλος derived from the Ancient Greek κρύος meaning "icy cold", because some philosophers believed the mineral to be a form of supercooled ice. Today, the term rock crystal is sometimes used as an alternative name for the purest form of quartz. Quartz belongs to the trigonal crystal system; the ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. In nature quartz crystals are twinned, distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive. Well-formed crystals form in a'bed' that has unconstrained growth into a void. However, doubly terminated crystals do occur where they develop without attachment, for instance within gypsum. A quartz geode is such a situation where the void is spherical in shape, lined with a bed of crystals pointing inward. Α-quartz crystallizes in the trigonal crystal system, space group P3121 or P3221 depending on the chirality.
Β-quartz belongs to space group P6222 and P6422, respectively. These space groups are chiral. Both α-quartz and β-quartz are examples of chiral crystal structures composed of achiral building blocks; the transformation between α- and β-quartz only involves a comparatively minor rotation of the tetrahedra with respect to one another, without change in the way they are linked. Although many of the varietal names arose from the color of the mineral, current scientific naming schemes refer to the microstructure of the mineral. Color is a secondary identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties. Pure quartz, traditionally called rock crystal or clear quartz, is colorless and transparent or translucent, has been used for hardstone carvings, such as the Lothair Crystal. Common colored varieties include citrine, rose quartz, smoky quartz, milky quartz, others; these color differentiation's arise from chromophores which have been incorporated into the crystal structure of the mineral.
Polymorphs of quartz include: α-quartz, β-quartz, moganite, cristobalite and stishovite. The most important distinction between types of quartz is that of macrocrystalline and the microcrystalline or cryptocrystalline varieties; the cryptocrystalline varieties are either translucent or opaque, while the transparent varieties tend to be macrocrystalline. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, its monoclinic polymorph moganite. Other opaque gemstone varieties of quartz, or mixed rocks including quartz including contrasting bands or patterns of color, are agate, carnelian or sard, onyx and jasper. Amethyst is a form of quartz that ranges from a dull purple color; the world's largest deposits of amethysts can be found in Brazil, Uruguay, France and Morocco. Sometimes amethyst and citrine are found growing in the same crystal, it is referred to as ametrine. An amethyst is formed. Blue quartz contains inclusions of fibrous crocidolite. Inclusions of the mineral dumortierite within quartz pieces result in silky-appearing splotches with a blue hue, shades giving off purple and/or grey colors additionally being found.
"Dumortierite quartz" will sometimes feature contrasting light and dark color zones across the material. Interest in the certain quality forms of blue quartz as a collectible gemstone arises in India and in the United States. Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. Natural citrines are rare. However, a heat-treated amethyst will have small lines in the crystal, as opposed to a natural citrine's cloudy or smokey appearance, it is nearly impossible to differentiate between cut citrine and yellow topaz visually, but they differ in hardness. Brazil is the leading producer of citrine, with much
In chemistry, a solution is a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent; the mixing process of a solution happens at a scale where the effects of chemical polarity are involved, resulting in interactions that are specific to solvation. The solution assumes the phase of the solvent when the solvent is the larger fraction of the mixture, as is the case; the concentration of a solute in a solution is the mass of that solute expressed as a percentage of the mass of the whole solution. The term aqueous solution is. A solution is a homogeneous mixture of two or more substances; the particles of solute in a solution cannot be seen by the naked eye. A solution does not allow beams of light to scatter. A solution is stable; the solute from a solution cannot be separated by filtration. It is composed of only one phase. Homogeneous means. Heterogeneous means; the properties of the mixture can be uniformly distributed through the volume but only in absence of diffusion phenomena or after their completion.
The substance present in the greatest amount is considered the solvent. Solvents can be liquids or solids. One or more components present in the solution other; the solution has the same physical state as the solvent. If the solvent is a gas, only gases are dissolved under a given set of conditions. An example of a gaseous solution is air. Since interactions between molecules play no role, dilute gases form rather trivial solutions. In part of the literature, they are not classified as solutions, but addressed as mixtures. If the solvent is a liquid almost all gases and solids can be dissolved. Here are some examples: Gas in liquid: Oxygen in water Carbon dioxide in water – a less simple example, because the solution is accompanied by a chemical reaction. Note that the visible bubbles in carbonated water are not the dissolved gas, but only an effervescence of carbon dioxide that has come out of solution. Liquid in liquid: The mixing of two or more substances of the same chemistry but different concentrations to form a constant.
Alcoholic beverages are solutions of ethanol in water. Solid in liquid: Sucrose in water Sodium chloride or any other salt in water, which forms an electrolyte: When dissolving, salt dissociates into ions. Solutions in water are common, are called aqueous solutions. Non-aqueous solutions are. Counter examples are provided by liquid mixtures that are not homogeneous: colloids, emulsions are not considered solutions. Body fluids are examples for complex liquid solutions. Many of these are electrolytes. Furthermore, they contain solute molecules like urea. Oxygen and carbon dioxide are essential components of blood chemistry, where significant changes in their concentrations may be a sign of severe illness or injury. If the solvent is a solid gases and solids can be dissolved. Gas in solids: Hydrogen dissolves rather well in metals in palladium. Liquid in solid: Mercury in gold, forming an amalgam Water in solid salt or sugar, forming moist solids Hexane in paraffin wax Solid in solid: Steel a solution of carbon atoms in a crystalline matrix of iron atoms Alloys like bronze and many others Polymers containing plasticizers The ability of one compound to dissolve in another compound is called solubility.
When a liquid can dissolve in another liquid the two liquids are miscible. Two substances that can never mix to form a solution are said to be immiscible. All solutions have a positive entropy of mixing; the interactions between different molecules or ions may be energetically favored or not. If interactions are unfavorable the free energy decreases with increasing solute concentration. At some point the energy loss outweighs the entropy gain, no more solute particles can be dissolved. However, the point at which a solution can become saturated can change with different environmental factors, such as temperature and contamination. For some solute-solvent combinations a supersaturated solution can be prepared by raising the solubility to dissolve more solute, lowering it; the greater the temperature of the solvent, the more of a given solid solute it can dissolve. However, most gases and some compounds exhibit solubilities that decrease with increased temperature; such behavior is a result of an exothermic enthalpy of solution.
Some surfactants exhibit this behaviour. The solubility of liquids in liquids is less temperature-sensitive than that of solids or gases; the physical properties of compounds such as melting point and boiling point change when other compounds are added. Together they are called colligative properties. There are several ways to quantify the amount of one compound dissolved in the other compounds collectively called concentration. Examples include molarity, volume fraction, mole fraction; the properties of ideal solutions can be calculated by the linear combination of the properties of
A laboratory is a facility that provides controlled conditions in which scientific or technological research and measurement may be performed. Laboratories used for scientific research take many forms because of the differing requirements of specialists in the various fields of science and engineering. A physics laboratory might contain a particle accelerator or vacuum chamber, while a metallurgy laboratory could have apparatus for casting or refining metals or for testing their strength. A chemist or biologist might use a wet laboratory, while a psychologist's laboratory might be a room with one-way mirrors and hidden cameras in which to observe behavior. In some laboratories, such as those used by computer scientists, computers are used for either simulations or the analysis of data. Scientists in other fields will use still other types of laboratories. Engineers use laboratories as well to design and test technological devices. Scientific laboratories can be found as research room and learning spaces in schools and universities, government, or military facilities, aboard ships and spacecraft.
Despite the underlying notion of the lab as a confined space for experts, the term "laboratory" is increasingly applied to workshop spaces such as Living Labs, Fab Labs, or Hackerspaces, in which people meet to work on societal problems or make prototypes, working collaboratively or sharing resources. This development is inspired by new, participatory approaches to science and innovation and relies on user-centred design methods and concepts like Open innovation or User innovation. One distinctive feature of work in Open Labs is phenomena of translation, driven by the different backgrounds and levels of expertise of the people involved. Early instances of "laboratories" recorded in English involved alchemy and the preparation of medicines; the emergence of Big Science during World War II increased the size of laboratories and scientific equipment, introducing particle accelerators and similar devices. The earliest laboratory according to the present evidence is a home laboratory of Pythagoras of Samos, the well-known Greek philosopher and scientist.
This laboratory was created when Pythagoras conducted an experiment about tones of sound and vibration of string. In the painting of Louis Pasteur by Albert Edelfelt in 1885, Louis Pasteur is shown comparing a note in his left hand with a bottle filled with a solid in his right hand, not wearing any personal protective equipment. Researching in teams started in the 19th century, many new kinds of equipment were developed in the 20th century. A 16th century underground alchemical laboratory was accidentally discovered in the year 2002. Rudolf II, Holy Roman Emperor was believed to be the owner; the laboratory is preserved as a museum in Prague. Laboratory techniques are the set of procedures used on natural sciences such as chemistry, physics to conduct an experiment, all of them follow the scientific method. Laboratory equipment refers to the various tools and equipment used by scientists working in a laboratory: The classical equipment includes tools such as Bunsen burners and microscopes as well as specialty equipment such as operant conditioning chambers, spectrophotometers and calorimeters.
Chemical laboratorieslaboratory glassware such as the beaker or reagent bottle Analytical devices as HPLC or spectrophotometersMolecular biology laboratories + Life science laboratoriesAutoclave Microscope Centrifuges Shakers & mixers Pipette Thermal cyclers Photometer Refrigerators and Freezers Universal testing machine ULT Freezers Incubators Bioreactor Biological safety cabinets Sequencing instruments Fume hoods Environmental chamber Humidifier Weighing scale Reagents Pipettes tips Polymer consumables for small volumes sterileLaboratory equipment is used to either perform an experiment or to take measurements and gather data. Larger or more sophisticated equipment is called a scientific instrument; the title of laboratory is used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories. These notably include: Film laboratory or Darkroom Clandestine lab for the production of illegal drugs Computer lab Crime lab used to process crime scene evidence Language laboratory Medical laboratory Public health laboratory Industrial laboratory In many laboratories, hazards are present.
Laboratory hazards might include poisons. Therefore, safety precautions are vitally important. Rules exist to minimize the individual's risk, safety equipment is used to protect the lab users from injury or to assist in responding to an emergency; the Occupational Safety and Health Administration in the United States, recognizing the unique characteristics of the laboratory workplace, has tailored a standard for occupational exposure to hazardous chemicals in laboratories. 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, its approach to them. In determining the proper Chemical Hygiene Plan for a particular business or laboratory, it is necessary to understand the requirements of the standard, evaluation of the current safety and environmental practi