The separate determination of xanthine and hypoxanthine in urine and blood plasma by an enzymatic differential spectrophotometric method

Abstract

The enzymatic spectrophotometric determination of oxypurines (hypoxanthine plus xanthine) in urine and blood plasma has been extended by the use of differential spectrophotometry at 280 and 292 nm to enable the separate determination of hypoxanthine and xanthine to be carried out. The method retains the high degree of accuracy and specificity of the determination of total oxypurines, and has shown good recoveries and reproducibility when applied to aqueous solutions and to urine. Although less precise when applied to plasma, the method is the only simple method at present available that enables the determination of hypoxanthine and xanthine to be carried out on this material.