AUTOMATED-DETERMINATION OF HYPOXANTHINE AND XANTHINE IN URINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH COLUMN-SWITCHING

We report a high-performance liquid chromatographic method with column switching for urinary hypoxanthine and xanthine. Analyses were carrie d out with both a reversed-phase column and an anion-exchange column c onnected by a column switch and controlled automatically by a computer ized system controller. The relationships between standard concentrati ons and peak heights were linear in a concentration range of 1 to 1000 nmol/ml. The recovery of hypoxanthine added to urine was 101.1%, and that of xanthine was 98.1%. With our method urinary hypoxanthine and x anthine can be measured accurately without any sample preparation othe r than filtration.