Chromatography Chromatography Affinity chromatography is a biochemical separation method that combines size fractionation capability of gel permeation chromatography with the ability to design a stationary phase that reversibly binds to a known subset of molecules. This method is usually used to: ...more on Wikipedia about "Affinity chromatography"
Capillary electrophoresis (CE) can be used to separate ionic species by their charge and frictional forces. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the influence of an electric field. Introduced in the 1960’s, the technique of capillary electrophoresis (CE) was designed to separate species based on their size to charge ratio in the interior of a small capillary filled with an electrolyte. ...more on Wikipedia about "Capillary electrophoresis"
Chiral column chromatography is a variant of column chromatography, where the stationary phase is chiral instead of achiral. The enantiomers of the same compound then differ in affinity to the stationary phase, thus they exit the column at different times. ...more on Wikipedia about "Chiral column chromatography"
Chromatography is a family of analytical chemistry techniques for the separation of mixtures. It involves passing the sample, a mixture which contains the analyte, in the "mobile phase", often in a stream of solvent, through the "stationary phase." The stationary phase retards the passage of the components of the sample. When components pass through the system at different rates they become separated in time, like runners in a mass-start foot race. Each component has a characteristic time of passage through the system, called a "retention time." Chromatographic separation is achieved when the retention time of the analyte differs from that of other components in the sample. ...more on Wikipedia about "Chromatography"
Column chromatography in chemistry is the preparative application of chromatography. It is used to obtain pure chemical compounds from a mixture of compounds on a scale from micrograms up to kilograms using large industrial columns. ...more on Wikipedia about "Column chromatography"
Countercurrent Chromatography(CCC) or Partition Chromatography is a category of liquid-liquid chromatography techniques. Chromatography in general is used to separate components of a mixture based on their differing affinities for mobile and stationary phases of a 'column'. The components can then be analyzed separatly by various sorts of detectors which may or may not be integrated into an apparatus. In liquid-liquid chromatography, both the mobile and stationary phases are liquid. In contrast, standard column chromatography uses a solid stationary phase and a liquid mobile phase, while gas chromatography uses a liquid stationary phase on a solid support and a gaseous mobile phase. By eliminating solid supports, permanent adsorption of the analyte onto the column is avoided, and a near 100% recovery of the analyte can be achieved. The instrument is also easily switched between various modes of operation by simply changing solvents. With liquid-liquid chromatography, researchers are not limited by the composition of the columns comercially available for their instrument. Nearly any pair of immiscible solutions can be used in liquid-liquid chromatography, and most instruments can be operated in standard or reverse-phase modes. Solvent costs are also generally cheaper than for HPLC. Another advantage is that experiments conducted in the lab can easily be scaled to industrial volumes. When GC or HPLC is done with large volumes, resolution is lost due to issues with surfact-to-volume ratios and flow dynamics; this is avoided when both phases are liquid. ...more on Wikipedia about "Countercurrent chromatography"
The distribution constant (or partition ratio), is the equilibrium constant for the distribution of an analyte in two immiscible solvents. For a particular solvent, it is equal to the ratio of its molar concentration in the stationary phase to its molar concentration in the mobile phase, also approximating the ratio of the solubility of the solvent in each phase. The term is often confused with partition coefficient or distribution coefficient, and is often represented by KD. ...more on Wikipedia about "Distribution constant"
The electron capture detector (ECD) is based on the emission of electrons from a foil containing radioactive nickel-63. The electrons formed are attracted to a positively charged anode, generating a steady current. As the sample moves into the detector by a nitrogen or 5% methane carrier gas (5% methane and 95% argon), analyte molecules capture the electons and reduce the current between the collector anode and a cathode. The analyte concentration is thus proportional to the degree of electron capture, and this detector is particularly sensitive to halogens, organometallic compounds, nitriles, or nitro compounds. The detection limit for electron capture detectors is 5 fg/s, and the detector commonly exhibits a 10,000-fold linear range. ...more on Wikipedia about "Electron capture detector"
Gas chromatography-mass spectrometry (GC-MS) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, fire investigation, environmental analysis, and explosives investigation. GC-MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification. ...more on Wikipedia about "Gas chromatography-mass spectrometry"
Gas-liquid chromatography (GLC), or simply gas chromatography (GC), is a type of chromatography in which the mobile phase is a carrier gas, usually an inert gas such as helium or nitrogen, and the stationary phase is a microscopic layer of liquid on an inert solid support. The stationary phase lines the inside of a very long very thin tube known as a column. ...more on Wikipedia about "Gas-liquid chromatography"
Gel permeation chromatography (GPC) also known as size exclusion chromatography (SEC) is a chromatographic method in which molecules are separated based on their size. This method is most widely used in the analysis of polymer molecular weights (or molar mass). The term GPC was used in the beginning of polymer analysis when people used glass columns filled with gels to perform GPC. Nowadays more and more automated and high pressure liquid chromatographic columns are used. Therefore GPC is an old terminology and size-exclusion chromatography (SEC) is the correct expression for the determination of molecular weights. ...more on Wikipedia about "Gel permeation chromatography"
High Performance Liquid Chromatography, also known as High Pressure Liquid Chromatography and usually abbreviated as HPLC, is a form of column chromatography used frequently in biochemistry and analytical chemistry. The analyte is forced through a column of the stationary phase in a liquid (mobile phase) at high pressure, which decreases the time the separated components remain on the stationary phase and thus the time they have to diffuse within the column. This leads to narrower peaks in the resulting chromatogram and thence to better resolution (it's easier to differentiate one peak from another) and sensitivity (tall, narrow peaks can be easier to discriminate from noise than shorter, broader peaks). ...more on Wikipedia about "High performance liquid chromatography"
The ion-exchange chromatography process allows the separation of ions and polar molecules based on the charge properties of the molecules. ...more on Wikipedia about "Ion exchange chromatography"
Liquid chromatography-mass spectrometry (LC-MS)is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (aka HPLC) with the mass analysis capabilities of mass spectrometry. LC-MS is a powerful technique used for many applications which has very high sensitivity and specificity. Generally its application is oriented towards the specific detection and potential identification of chemicals in the presence of other chemicals (in a complex mixture). ...more on Wikipedia about "Liquid chromatography-mass spectrometry"
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In 1984, the Terabe group reported a technique that enabled capillary electrophoresis (CE) instrumentation to be used in the separation of neutral (as well as ionic) species. In micellar electrokinetic chromatography (MEKC), samples are separated by differential partitioning between a pseudo-stationary micellar phase and an aqueous mobile phase.5 In most applications, MEKC is performed in open capillaries under alkaline conditions to generate a strong electroosmotic flow. The basic set-up and detection methods used for MEKC are the same as those used in CE. The difference is that the solution contains a surfactant at a concentration that is greater than the critical micelle concentration (CMC). Above this concentration, surfactant monomers are in equilibrium with micelles. Sodium dodecyl sulfate (SDS) is the most commonly used surfactant in MEKC applications. The anionic character of the sulfate groups of SDS cause the surfactant and micelles to have ...more on Wikipedia about "Micellar electrokinetic chromatography"
The Van Deemter equation for plate height" ...more on Wikipedia about "Van Deemter's equation"
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