Absorption: The process where a chemical entity enter the bulk of a liquid, solid or gasphase. In chromatography the term usually signifies the process by which asolute partitions into a liquid-like stationary phase.Additive:A compound added to the mobile phase to improve the chromatographicanalysis.
Adjusted Retention Volume, V´R ( or Time, t´R ): The retention volume ( or time ) minus the Hold-up volume ( or time ). Note the difference between this and the retention volume ( or time )
Adsorbent: The packing used in adsorption chromatography.Adsorption:The process where a chemical entity is accumulated on a surface.
Adsorption Chromatography: Separation based on differences in adsorption of the components to the stationary phase surface.
Adsorption isotherm: A plot of the amount of solute per solid phase unit ( weight, volume, areaetc) as a function of its concentration in the bulk phase ( liquid or gasphase ).
Affinity Chromatography: Chromatographic separation based on a specific interaction between the analyte and a ligand bound to the stationary phase surface.
Agarose:A separation medium for the separation of biomolecules. It is a highmolecular weight polysaccharide.
Adjusted Retention Volume, V´R ( or Time, t´R ): The retention volume ( or time ) minus the Hold-up volume ( or time ). Note the difference between this and the retention volume ( or time )
Adsorbent: The packing used in adsorption chromatography.Adsorption:The process where a chemical entity is accumulated on a surface.
Adsorption Chromatography: Separation based on differences in adsorption of the components to the stationary phase surface.
Adsorption isotherm: A plot of the amount of solute per solid phase unit ( weight, volume, areaetc) as a function of its concentration in the bulk phase ( liquid or gasphase ).
Affinity Chromatography: Chromatographic separation based on a specific interaction between the analyte and a ligand bound to the stationary phase surface.
Agarose:A separation medium for the separation of biomolecules. It is a highmolecular weight polysaccharide.
Alumina: Porous aluminium oxide used as an adsorbent in chromatography .
Amphoteric ion-exchange phase: A stationary phase that has both positively and negatively charged ionicgroups bonded to it.
Analyte: The chemical entity to be analyzed. In chromatography the term solute isalso frequently used.
Anion exchange chromatography: The chromatographic process that is used to separate anions by using anionized positively charged stationary phase. Tetraalkylammonium ions are often used as anion exchange functional groups.
Baseline: The part of the chromatogram where the detector measures the mobile phase only.
Bed Volume : Synonymous to Column Volume
BET-method: A method for determining the surface area of a solid that was developed byBrunauer, Emmet and Teller. It uses the known size of the nitrogen moleculein combination with experimental data of adsorption-condensation ofnitrogen to the solid.
Bonded phase : A stationary phase which is covalently bonded to the support particles or the inside wall of a tube.
Breakthrough volume: When a solute is continuously pumped through a column, it will start toelute at a certain volume, this is the breakthrough volume.
Capacity factor : See retention factor. IUPAC discourage its usage.
Capillary column: Columns with an inner diameter less than 0.5 mm.
Capillary LC: Liquid chromatography performed by using a capillary column.
Baseline: The part of the chromatogram where the detector measures the mobile phase only.
Bed Volume : Synonymous to Column Volume
BET-method: A method for determining the surface area of a solid that was developed byBrunauer, Emmet and Teller. It uses the known size of the nitrogen moleculein combination with experimental data of adsorption-condensation ofnitrogen to the solid.
Bonded phase : A stationary phase which is covalently bonded to the support particles or the inside wall of a tube.
Breakthrough volume: When a solute is continuously pumped through a column, it will start toelute at a certain volume, this is the breakthrough volume.
Capacity factor : See retention factor. IUPAC discourage its usage.
Capillary column: Columns with an inner diameter less than 0.5 mm.
Capillary LC: Liquid chromatography performed by using a capillary column.
Cartridge column: A column type that has no endfittings and is held in a cartridge holder. Thecolumn comprises a tube and packing contained by frits in each end of thetube.
Cation exchange chromatography: The chromatographic process that is used to separate cations by using aionized negatively charged stationary phase. A sulfonic acid is an oftenused cation exchange functional group.
Channeling: Poor packing or erosion creates voids in the packed bed. Channeling occursbecause the mobile phase moves more rapidly in these these voids than inother parts of the bed.
Chemisorption: Adsorption, usually irreversible, accompanied by a chemical reaction withthe solid surface.Chiral stationary phase:Stationary phases that can separate enantiomers.
Chlorosilane: A reagent which is used to create siloxane bonds with silanol groups. Threetypes are used, monochlorosilanes;R1R2R3-Si-Cl, dichlorosilanes; R1R2-SiCl2and trichlorosilanes; R1-SiCl3 . Ri can have various structures but is oftenan alkyl group.
Chromatograph (noun): The instrument which is used to carry out a chromatographic separation
Co-ion: A ion of the same sign of charge as the ionic groups making up thestationary phase.
Column: The tube and the stationary phase through which the mobile phase flow.
Column back pressure: The difference in pressure between the column inlet and outlet.
Chromatograph (noun): The instrument which is used to carry out a chromatographic separation
Co-ion: A ion of the same sign of charge as the ionic groups making up thestationary phase.
Column: The tube and the stationary phase through which the mobile phase flow.
Column back pressure: The difference in pressure between the column inlet and outlet.
Column chromatography: The form of chromatography which uses a column or tube to fix the stationaryphase.
Column plate number: See Plate number.
Column switching : Two or more columns connected by switching valves. Fractions from one columnare switched to a second column.
Column Volume : The volume of the empty column tube.
Competing base: A basic compound, often a small amine, added to the mobile phase with theintention to improve the peak shape of a basic solute.
Column switching : Two or more columns connected by switching valves. Fractions from one columnare switched to a second column.
Column Volume : The volume of the empty column tube.
Competing base: A basic compound, often a small amine, added to the mobile phase with theintention to improve the peak shape of a basic solute.
Counterion: When the term is used in ion exchange chromatography it means the ions addedto the mobile phase with charge opposite to the ions bonded to thestationary phase.
Coverage: The concentration of bonded phase on the silica support, usually expressedin mol/m2 or weight %.
Cross-links: Bonds that connect one polymer chain to another. Cross-linking is importantfor resins because it governs its swelling and diffusion characteristics.Degassing:The removal of dissolved gas from the mobile phase.
Detector: An instrument that measures the change in composition of the eluent.
Displacement chromatography: A form of non linear chromatography where the migration of the solutes isdue to a displacement by an additive that strongly adsorbs to the stationaryphase.
Detector: An instrument that measures the change in composition of the eluent.
Displacement chromatography: A form of non linear chromatography where the migration of the solutes isdue to a displacement by an additive that strongly adsorbs to the stationaryphase.
Dynamic coating: Modification of the properties of the stationary phase surface by using anadditive in the mobile phase that adsorbs to the surface.
Effluent : The mobile phase that exits the column.
Eluate: The solute - mobile phase mixture which exits the column.
Eluate: The solute - mobile phase mixture which exits the column.
Eluent: Another word for the mobile phase.
Eluite: The eluted solute.
Elute: The use of elution chromatography.
Elution: The passing of mobile phase through the chromatographic bed to transportsolutes.
(Size) Exclusion Chromatography: Separation based mainly on differences in molecular size. Differences in shape and/or charge may also contribute to the separation.
Extracolumn effects: The effect on bandbroadening by all parts in a chromatographic system,except the column.
Extra-column Volume: The volumes of the injector, detector and connecting tubes. ( The term dead-volume is often used for this volume, IUPAC discourage this term.)
Fast protein LC (FPLC): HPLC of proteins, generally in glass columns with spherical microbeads andmoderate pressure.
Flow rate: The volume of the mobile phase that passes through the column per unit time.
Frontal chromatography : A chromatographic technique in which the sample is continously added to thecolumn inlet.
Fronting: Asymmetry of a peak such that its rear in a chromatogram is steeper than its front.
(Size) Exclusion Chromatography: Separation based mainly on differences in molecular size. Differences in shape and/or charge may also contribute to the separation.
Extracolumn effects: The effect on bandbroadening by all parts in a chromatographic system,except the column.
Extra-column Volume: The volumes of the injector, detector and connecting tubes. ( The term dead-volume is often used for this volume, IUPAC discourage this term.)
Fast protein LC (FPLC): HPLC of proteins, generally in glass columns with spherical microbeads andmoderate pressure.
Flow rate: The volume of the mobile phase that passes through the column per unit time.
Frontal chromatography : A chromatographic technique in which the sample is continously added to thecolumn inlet.
Fronting: Asymmetry of a peak such that its rear in a chromatogram is steeper than its front.
Gel filtration chromatography (GFC): Chromatographic separation according to molecular size usually performed inan aqueous mobile phase on soft gels such as polydextrans.
Gradient elution: The chromatographic technique by which a mobil phase gradient is used tomodulate the retention times. Usually the mobile phase composition changesso that its strength increases with time.
Graphitized carbon packing: A stationary phase consisting of pure graphitic carbon.
Guard column: A small column that protects the analytical column from contamination, it isplaced between the injector and the analytical column.
Heart cutting: A term used in preparative chromatography and column switching for thecollection of the center of a peak.
High performance liquid chromatography (HPLC): A term coined for the modern and instrumentally developed form of columnliquid chromatography. It is characterised by high flow rates and high backcolumn pressure.
Hold-up Volume, ( VM ) ( or Time ( tM ) ): The volume ( or corresponding time ) of mobile phase required to elute a component that does not interact with the stationary phase. I.e. the component is not retained by the stationary phase.
Hydrophobic Interaction Chromatography (HIC): A chromatographic technique which is primarly used to separate proteins. Thetechnique is characterised by a hydrophilic solid support with a lowcoverage of short carbon chains. The mobile phase is a buffered watersolution with a steep gradient of decreasing salt concentration.
Hold-up Volume, ( VM ) ( or Time ( tM ) ): The volume ( or corresponding time ) of mobile phase required to elute a component that does not interact with the stationary phase. I.e. the component is not retained by the stationary phase.
Hydrophobic Interaction Chromatography (HIC): A chromatographic technique which is primarly used to separate proteins. Thetechnique is characterised by a hydrophilic solid support with a lowcoverage of short carbon chains. The mobile phase is a buffered watersolution with a steep gradient of decreasing salt concentration.
IC: Abbreviation for ion chromatography
Imprinted phases: Stationary phases which are generated in the presence of a template moleculeso that a "footprint" of the molecule is created on the stationary phase.The imprinted phase has a strong selectivity for the template molecule.
Indirect detection: A detection technique where the solute is indirectly detected by measuringthe change in mobile phase composition at column outlet. A prerequisite forthis technique is that the adsorption isotherm of a component in the mobilephase depends on the concentration of the solute. E.g. a non-UV absorbingsolute is indirectly detected with an UV-detector by adding an UV absorbingcomponent to the mobile phase. If the adsorption isotherm of this componentdepends on the concentration of the solute, its variation in concentrationat the column outlet, caused by the elution of the solute, can be detectedwith an UV-detector.
(Sample) Injector: A device by which a sample is introduced into the mobile phase.
Inlet: The part of the column where the mobile phase and the solute enter.
(Sample) Injector: A device by which a sample is introduced into the mobile phase.
Inlet: The part of the column where the mobile phase and the solute enter.
In-line filter: A filter that is placed between the column and the injector and whichprevents particulate matter to damage the column.
Interparticle porosity (ee): The interparticle porosity is; ee = Ve/Vc where Ve is the interstitialvolume and Vc the total column volume.
Interstitial volume: In chromatography; the volume between the particles in a packed column.
Intraparticle porosity(ei): The fraction of the particle volume that is in pores; ei = Vi/Vparticlewhere Vi is the intraparticle volume and Vparticle the particle volume.
Intraparticle volume: The volume inside the pores of the particles.
Ion Exchange Chromatography: Separation based on differences in the distribution between the mobile phase and a charged stationary phase.
Ion chromatography (IC): A technique in which low concentrations of ionic solutes are determined byusing ion exchangers of low exchange capacity and mobile phase with lowionic strength.
Ion Exchange Chromatography: Separation based on differences in the distribution between the mobile phase and a charged stationary phase.
Ion chromatography (IC): A technique in which low concentrations of ionic solutes are determined byusing ion exchangers of low exchange capacity and mobile phase with lowionic strength.
Ion exclusion: The exclusion of co-ions from the surface layer. In chromatography the ionexclusion effect implicates that co-ions migrates faster through the columnthan a neutral molecule.
Ion moderated partitioning chromatography: A technique used for separating carbohydrates by using a strong cationexchanger.
Ion pair chromatography: A form of reversed phase chromatography in which a charged organic molecule,the ion pair reagent, is added to the mobile phase. The ion pair reagentadsorbs to the stationary phase surface and creates a charged surface layer.Ions of opposite charge are attracted to the charged surface layer and ionsof the same charge are repelled . The retention of ions is modulated bychanging the concentration of ion pair reagent in the mobile phase.
Isocratic chromatography: A chromatographic run with a constant mobile phase composition
Linear chromatography: Chromatography performed in the linear range of the adsorption isotherm forthe solute.
Isocratic chromatography: A chromatographic run with a constant mobile phase composition
Linear chromatography: Chromatography performed in the linear range of the adsorption isotherm forthe solute.
Linear velocity: The velocity of the mobile phase through the column expressed as m/s. It isestimated as the column length divided by the time it takes for anon-retained compound to pass the column
Liquid chromatography: Chromatography by using a liquid as mobile phase, usually performed in acolumn.
Mobile phase: The fluid that flows through the chromatographic column.
Mobile phase velocity : The linear velocity ( u ) of the mobile phase through the column. It is usually estimated from the time it takes for an unretained compound to pass through the column, tM, and the column length, L. u = L / tM
Open-Tubular Column : A column in which the stationary phase coates the inner wall. The column diameter is usually small, e.g. 0.1 mm.
Partition Chromatography : Separation based mainly on differences in solubilities between the mobile and stationary phase.
Packed Column : A column containing a solid packing material.
Peak: The part of the chromatogram where the detector response is caused by a solute.
Peak Area : The area of the peak as registered by the detector.
Peak maximum : The point on the peak where detector response is maximum.
Peak-Width : The width of the peak registrered by the detector. It may be represented in the dimension time or volume. For a Gaussian formed peak, the peak-width is related to the standard deviation (s) of the peak. The peak width can be estimated by several different methods. For example:
Peak-width at Base, wb = 4s
Peak-width at Half Height, wh = 2.355s
Peak-width at Inflection Point, wi = 2s
Phase ratio : A characteristic constant of a column. It is a measure of the volume ( or area ) of the stationary phase per unit volume of the mobile phase in the column.
Plate Height ( H) : The column length ( L ) divided by the plate number:
H = L / N
Plate Number ( N ) A dimensionless number that is a measure of the effectivity of a column.
N = ( VR / s)2
Pressure drop : The difference in pressure between the inlet and outlet in a chromatographic system
Reduced mobile phase velocity ( n ) : A dimensionless measure of the mobile phase velocity compared to diffusion into the pores. n = u*dp/DM
where u = linear velocity of the mobile phase; dp = particle diameter and DM = diffusion coefficient of the solute in the mobile phase.
(Peak ) Resolution ( Rs )
A measure how well two peaks are separated. It is defined as:
Rs = 2(tR2 - tR1) / (wb1 + wb2)
tR = Retention time, wb = peak width at base
Reduced Plate Height ( h ) : A dimensionless number defined as the ratio of the plate height divided by the particle diameter.
Relative retention time( usually denoted RRT) :RRT= tR2/tR1 = VR2/VR1
Note the difference between this and the separation factor. RRT is often used to identify peaks from system to system.
Retention Factor (k): The ratio of the adjusted retention volume ( or time ) and the hold-up volume ( or time ); k = V´R/ VM = t´R / tM
The retention factor has for many years also been called the capacity factor, k´. This usage is not recommended by IUPAC.
Retention Volume ( VR ) ( or Time ( tR ): The volume ( or corresponding time ) of mobile phase that passes through the column between sample injection and the emergence of the peak maximum. Note the difference between this and the adjusted retention volume ( or time ).
Separation Factor ( a ) : The relative retention values for two adjacent peaks;
a = V´R2/V´R1 = k2 / k1
V´R2 is chosen to be the larger value so that the separation factor becomes larger than unity.
Solid support : The solid that holds the stationary phase.
Solute : A term for the sample components.
Stationary phase : One of the two phases in a chromatographic system. In a chromatographic system the analyte is distributed between the mobile phase and the stationary phase.
Tailing : Asymmetry of a peak such that its front in a chromatogram is steeper than its rear.
Void Volume : The volume in the column that is filled with the mobile phase. In the ideal case it is equal to the mobile phase hold up volumne.
Mobile phase: The fluid that flows through the chromatographic column.
Mobile phase velocity : The linear velocity ( u ) of the mobile phase through the column. It is usually estimated from the time it takes for an unretained compound to pass through the column, tM, and the column length, L. u = L / tM
Open-Tubular Column : A column in which the stationary phase coates the inner wall. The column diameter is usually small, e.g. 0.1 mm.
Partition Chromatography : Separation based mainly on differences in solubilities between the mobile and stationary phase.
Packed Column : A column containing a solid packing material.
Peak: The part of the chromatogram where the detector response is caused by a solute.
Peak Area : The area of the peak as registered by the detector.
Peak maximum : The point on the peak where detector response is maximum.
Peak-Width : The width of the peak registrered by the detector. It may be represented in the dimension time or volume. For a Gaussian formed peak, the peak-width is related to the standard deviation (s) of the peak. The peak width can be estimated by several different methods. For example:
Peak-width at Base, wb = 4s
Peak-width at Half Height, wh = 2.355s
Peak-width at Inflection Point, wi = 2s
Phase ratio : A characteristic constant of a column. It is a measure of the volume ( or area ) of the stationary phase per unit volume of the mobile phase in the column.
Plate Height ( H) : The column length ( L ) divided by the plate number:
H = L / N
Plate Number ( N ) A dimensionless number that is a measure of the effectivity of a column.
N = ( VR / s)2
Pressure drop : The difference in pressure between the inlet and outlet in a chromatographic system
Reduced mobile phase velocity ( n ) : A dimensionless measure of the mobile phase velocity compared to diffusion into the pores. n = u*dp/DM
where u = linear velocity of the mobile phase; dp = particle diameter and DM = diffusion coefficient of the solute in the mobile phase.
(Peak ) Resolution ( Rs )
A measure how well two peaks are separated. It is defined as:
Rs = 2(tR2 - tR1) / (wb1 + wb2)
tR = Retention time, wb = peak width at base
Reduced Plate Height ( h ) : A dimensionless number defined as the ratio of the plate height divided by the particle diameter.
Relative retention time( usually denoted RRT) :RRT= tR2/tR1 = VR2/VR1
Note the difference between this and the separation factor. RRT is often used to identify peaks from system to system.
Retention Factor (k): The ratio of the adjusted retention volume ( or time ) and the hold-up volume ( or time ); k = V´R/ VM = t´R / tM
The retention factor has for many years also been called the capacity factor, k´. This usage is not recommended by IUPAC.
Retention Volume ( VR ) ( or Time ( tR ): The volume ( or corresponding time ) of mobile phase that passes through the column between sample injection and the emergence of the peak maximum. Note the difference between this and the adjusted retention volume ( or time ).
Separation Factor ( a ) : The relative retention values for two adjacent peaks;
a = V´R2/V´R1 = k2 / k1
V´R2 is chosen to be the larger value so that the separation factor becomes larger than unity.
Solid support : The solid that holds the stationary phase.
Solute : A term for the sample components.
Stationary phase : One of the two phases in a chromatographic system. In a chromatographic system the analyte is distributed between the mobile phase and the stationary phase.
Tailing : Asymmetry of a peak such that its front in a chromatogram is steeper than its rear.
Void Volume : The volume in the column that is filled with the mobile phase. In the ideal case it is equal to the mobile phase hold up volumne.
very good and imformative
ReplyDeleteregards,
dilip kumar
gujarat