Chromatography

Chromatography is a separation technique in which sample components distributes themselves between two immiscible phases (mobile phase and stationary phase) to varying degrees. Consequently, they migrate at different rates through the S.P. under the influence of the M.P.

signal Time B A tr(A) to tr(B) A+B AB What is Chromatography?

Glossary of chromatographic terms Stationary phase- –Phase that stays intact. –Usually a viscous liquid coated on the inside of a capillary tube or on the surface of solid particles –May contain minerals, organic or inorganic polymers or liquid-coated solids Mobile phase –Phase that moves. –May be gases, liquids or supercritical fluids.

Columns –Usually contains the stationary phase –Either packed or open tubular –Packed columns are filled with particles of the stationary phase –The stationary phase is coated on the inside of the column in open tubular columns Eluent - Fluid entering the column Effluent –Fluid leaving the column Elution –Process of passing a liquid or gas through a chromatography column

Elution order Compounds that have a low affinity for the column packing and/or a high solubility in the mobile phase are washed through the column quickly. Compounds that stick tightly to the column packing and/or have a low solubility in the mobile phase solvent move more slowly. Developing an HPLC separation requires finding a combination of column packing and mobile phase that provides just the right balance of affinity and solubility to make the compounds of interest move at different speeds.

Classification of chromatography according to the types of M.P and S.P M.P :mobile phase, S.M: stationary phase,