Determination of creatinine and purine derivatives in ruminants' urine by reversed-phase high-performance liquid chromatography.

A procedure is described for the rapid and simultaneous determination of allantoin, creatinine, uric acid, hypoxanthine and xanthine in sheep urine. Separation was achieved on a Novapak C18 column under isocratic conditions. The mobile phase was potassium phosphate buffer (10 mM, pH 4.0). A flow-rate of 0.5 ml/min, detection at 218 nm and a column temperature of 25 degrees C were employed with a total analysis time of less than 15 min. Detection limits for allantoin, creatinine, uric acid, hypoxanthine and xanthine were 1.0, 0.5, 0.5, 0.5 and 0.2 micrograms/ml, respectively, at a signal-to-noise ratio of 3 in a 20-microliters injection volume of tenfold-diluted urine. This sensitivity permits the precise determination of these compounds in ruminants' urine.