The quantitative determination of metabolites of 6-mercaptopurine in biological materials. IV. An improved separation method for twentytwo compounds related to purine and 6-thiopurine metabolism using high-pressure liquid cation-exchange chromatography.

An improved method is described for the separation of 22 compounds normally related to purine and 6-thiopurine metabolism in biological materials using high-pressure liquid cation-exchange chromatography on strongly acidic exchange resin. The column (0.8 X 100 cm) is eluted with 0.4 M ammonium formate, pH 4.6, at a linear flow velocity of 5.2 cm.min--1 at 50 degrees C. The elution volumes of sulphate anions, allopurinol, 6-thioxanthine, adenine, adenosine, and guanosine are demonstrated additionally to further 16 purine and 6-thiopurine compounds.