EFFECT OF FUNCTIONAL-GROUPS ON THE RETENTION BEHAVIOR OF ANIONS IN ION CHROMATOGRAPHY USING A COATED SILICA COLUMN

The effect of functional groups on the retention behaviour o some anions was investigated in ion chromatography using ODS columns coated with several quaternary ammonium or phosphonium salts that have various free alkyl groups on the nitrogen and phosphorus atoms. The retention behaviour of strongly retained monovalent anions, such as nitrate and bromide, was greatly affected by the alkyl groups. However, those of divalent and weakly retained monovalent anions were little affected. The retention of anions on the quaternary phosphorus atom were stronger than those on the quaternary nitrogen atom.