Simultaneous measurements of creatinine and purine derivatives in ruminant's urine using ion-pair HPLC

A new and sensitive ion-pair RP-HPLC method was developed for concomitant measurement of the creatinine and purine derivatives (PD): allantoin, uric acid, and hypoxanthine using allopurinol as internal standard. Urine was chromatographed on a Symmetry C-18 column, using UV detection. Elution with a gradient of methanol in potassium phosphate buffer, pH = 4, containing 3 mM 1-octane-sulfonic acid, sodium salt yielded sharp, well-resolved peaks within 25 min. Application of this method permits the precise determination of these compounds in sheep urine.