Chromatography
Subtle differences in a compound's partition coefficient result in differential retention on the stationary phase and thus affect the separation.[7][8] He developed the technique and coined the term chromatography in the first decade of the 20th century, primarily for the separation of plant pigments such as chlorophyll, carotenes, and xanthophylls.Since these components separate in bands of different colors (green, orange, and yellow, respectively) they directly inspired the name of the technique.[9] Chromatography technique developed substantially as a result of the work of Archer John Porter Martin and Richard Laurence Millington Synge during the 1940s and 1950s, for which they won the 1952 Nobel Prize in Chemistry.When one make one solvent immobile (by adsorption on a solid support matrix) and another mobile it results in most common applications of chromatography.This allows omission of initial clearing steps such as centrifugation and filtration, for culture broths or slurries of broken cells.Thin-layer chromatography (TLC) is a widely employed laboratory technique used to separate different biochemicals on the basis of their relative attractions to the stationary and mobile phases.TLC is very versatile; multiple samples can be separated simultaneously on the same layer, making it very useful for screening applications such as testing drug levels and water purity.Packed columns are the routine workhorses of gas chromatography, being cheaper and easier to use and often giving adequate performance.However, molecules that are larger than the average pore size of the packing are excluded and thus suffer essentially no retention; such species are the first to be eluted.Expanded-bed adsorption (EBA) chromatography is a convenient and effective technique for the capture of proteins directly from unclarified crude sample.A change to elution buffer while maintaining upward flow results in desorption of the target protein in expanded-bed mode.It can provide a non-denaturing orthogonal approach to reversed phase separation, preserving native structures and potentially protein activity.Thus, the sample is applied to the column in a buffer which is highly polar, which drives an association of hydrophobic patches on the analyte with the stationary phase.In 2012, Müller and Franzreb described the effects of temperature on HIC using Bovine Serum Albumin (BSA) with four different types of hydrophobic resin.[28] Using temperature to effect change allows labs to cut costs on buying salt and saves money.Hydrodynamic chromatography (HDC) is derived from the observed phenomenon that large droplets move faster than small ones.[33] In a study comparing the two types of separation, Isenberg, Brewer, Côté, and Striegel use both methods for polysaccharide characterization and conclude that HDC coupled with multiangle light scattering (MALS) achieves more accurate molar mass distribution when compared to off-line MALS than SEC in significantly less time.[35] This is largely due to SEC being a more destructive technique because of the pores in the column degrading the analyte during separation, which tends to impact the mass distribution.[35] However, the main disadvantage of HDC is low resolution of analyte peaks, which makes SEC a more viable option when used with chemicals that are not easily degradable and where rapid elution is not important.[37] Their design was able to achieve separations using an 80 mm long channel on the timescale of 3 minutes for particles with diameters ranging from 26 to 110 nm, but the authors expressed a need to improve the retention and dispersion parameters.[37] In a 2010 publication by Jellema, Markesteijn, Westerweel, and Verpoorte, implementing HDC with a recirculating bidirectional flow resulted in high resolution, size based separation with only a 3 mm long channel.[37] For a biological application, in 2007, Huh, et al. proposed a microfluidic sorting device based on HDC and gravity, which was useful for preventing potentially dangerous particles with diameter larger than 6 microns from entering the bloodstream when injecting contrast agents in ultrasounds.Two-dimensional chromatography aims to increase the resolution of these peaks by using a second column with different physico-chemical (chemical classification) properties.[40] An example of a TDC separation is where the sample is spotted at one corner of a square plate, developed, air-dried, then rotated by 90° and usually redeveloped in a second solvent system.[40][41] The simulated moving bed (SMB) technique is a variant of high performance liquid chromatography; it is used to separate particles and/or chemical compounds that would be difficult or impossible to resolve otherwise.This valve arrangement provides for sample and solvent feed and analyte and waste takeoff at appropriate locations of any column, whereby it allows switching at regular intervals the sample entry in one direction, the solvent entry in the opposite direction, whilst changing the analyte and waste takeoff positions appropriately as well.The stationary phase is a resin composed of beads, usually of cross-linked agarose, packed into a cylindrical glass or plastic column.CPC instruments are commercially available for laboratory, pilot, and industrial-scale separations with different sizes of columns ranging from some 10 milliliters to 10 liters in volume.It is distinguished from hydrophilic interaction liquid chromatography (HILIC) in that the retention mechanism is due to adsorption rather than partitioning.
Chromatography (album)Continuum mechanicsFick's laws of diffusionMomentumEnergyClausius–Duhem (entropy)Solid mechanicsDeformationElasticitylinearPlasticityHooke's lawStressStrainFinite strainInfinitesimal strainCompatibilityBendingContact mechanicsfrictionalMaterial failure theoryFracture mechanicsFluid mechanicsFluidsStaticsDynamicsArchimedes' principleBernoulli's principleNavier–Stokes equationsPoiseuille equationPascal's lawViscosityNewtoniannon-NewtonianBuoyancyMixingPressureLiquidsAdhesionCapillary actionCohesion (chemistry)Surface tensionAtmosphereBoyle's lawCharles's lawCombined gas lawFick's lawGay-Lussac's lawGraham's lawPlasmaRheologyViscoelasticityRheometryRheometerSmart fluidsElectrorheologicalMagnetorheologicalFerrofluidsBernoulliCauchyCharlesGay-LussacGrahamNewtonNavierPascalStokesTruesdellChemistryOutlineGlossaryHistorytimelineMatter PhaseChemical reactionAcid–base reactionChemical equilibriumChemical lawAnalytical chemistryBiochemistryOrganic chemistryInorganic chemistryPhysical chemistryChemistList of chemistry awardsList of journalsList of unsolved problemschemical analysislaboratory techniqueseparationmixturepartition coefficientpurificationbiological pigmentsHistory of chromatographyMikhail TsvetWarsawpigmentschlorophyllcarotenesxanthophyllsseparation processesArcher John Porter MartinRichard Laurence Millington SyngeNobel Prize in Chemistrypaper chromatographygas chromatographyhigh-performance liquid chromatographysamplespectrophotometermass spectrometerEluotropic seriescapillary electrochromatographyKovats' retention indexsilicacelluloseColumn chromatographygradientexpanded bed adsorptionslurriesthin-layer chromatographycompoundsRetention factorsolutionchromatography paper