DETERMINATION OF CREATININE IN SERUM AND URINE BY A RAPID LIQUID-CHROMATOGRAPHIC METHOD

We describe an HPLC ion-pair procedure for rapid and specific evaluationof creatinineinserum and urine. We used a 15 cm x 4.6 mmODS column with a 50/50 (by vol) mixture of sodium decanesulfonic acid (10 mmol/L, pH 3.2) and methanoland measuredabsorbance at 236 nm. Serum (100 tL) or 30-fold-diluted urine (100 L) was added to 400 pL of acetone. After centrifugation,the supemates (300 L) were dried, reconstituted with the mobile phase, and injected into the HPLC. Assay precision was tested for concentrations of 10, 29, and 130mg/Land yielded, respectively, 3.1%, 2.1%, and 1.1% for within-dayCV and 2.8%, 2.1%, and 2.2% for totalCV. Analytical recovery was 102 (±6.7)%. Unearitywas demonstrated in the 0-200 mg/L range for serum and 0-3.5 g/L range for urine (r 0.999). The detection limit for creatmine (signal-to-noiseratio = 3) was 0.5 mg/L. We used cimetidinefor internalstandardization.Correlationwasgood between this procedureand the Jaff#{k2i3n3e}tic,the enzymatic (creatinineamidohydrolase),and the Fuller’searth alkaline picrate methods.