Simultaneous determination of allantoin and oxypurines in biological fluids by high-performance liquid chromatography

A high-performance liquid chromatographic method is described for the separation and quantification of allantoin and oxypurines in plasma and urine samples. Urine was analyzed directly and plasma after acid deproteinisation with perchloric acid. Separation and quantification of purine derivatives was achieved using two Spherisorb ODS-5 column (250 mm x 4.6 mm I.D.) connected in series together with a NH4H2PO4-NH4H2PO4-acetonitrile (80:20) gradient and monitoring the effluent at 205 nm. The average recoveries of standard compounds added to urine and plasma samples were 96 and 97%, respectively, using allopurinol as internal standard. The within-day variability was less than 7% and the day-to-day coefficient of variation less than 11% indicating a good precision of the method.