a strong anion-exchange column coupled to a strong cation-exchange column with acetate buffer as eluent or reversed-phase ion-pair chromatography on octadecylsilica with methanol-water containing 1-heptanesulphonic acid as the mobile phase is described for the simultaneous separation of 5-aminolaevulinic acid and porphobilinogen .
C0003075
anion
C0022023
ion