pH-zone-refining counter-current chromatography: a displacement mode applied to separation of dinitrophenyl amino acids.
A new mode of pH-zone-refining counter-current chromatography operates in a manner analogous to displacement chromatography. The method uses a retainer base (acid) in the stationary phase to retain analytes in the column and a displacer acid (base) to elute the analytes in the decreasing order of pKa and hydrophobicity. The elution produces a train of highly concentrated rectangular solute peaks with minimum overlap. Utility of the method is demonstrated in the separation of dinitrophenyl amino acids in a two-phase solvent system composed of methyl tert.-butyl ether and water. Compared with the original mode of pH-zone-refining counter-current chromatography, the present mode is more amenable to ligand-affinity separation which may cover a broader range of analytes including non-ionizable compounds.
Ito
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Laboratory of Biophysical Chemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
Ma
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Y
D000596:Amino Acids / Q000032:analysis*; D002845:Chromatography / Q000379:methods*; D004136:Dinitrobenzenes / Q000032:analysis*; D006863:Hydrogen-Ion Concentration
D000596:Amino Acids; D004136:Dinitrobenzenes