Measurement of nephrolithiasis urinary markers by capillary electrophoresis

A previously developed method for screening organic acidurias by capillary electrophoresis has been validated for oxalate and citrate measurement in u rine. Sample pretreatment is minimum, just acidification and centrifugation . Detection is by direct UV. Validation parameters of the method can be con sidered adequate. Response is linear for both analytes in standards and sam ples. The assayed ranges were 200-1000 mg/l for citrate and 10-200 mg/l for oxalate. Recoveries ranged from 99.4+/-3 to 101.7+/-2.4%, maximum imprecis ion in oxalate concentration was of 7.6% RSD and limits of detection in sam ples were 0.67 mg/l for oxalate and 25.9 mg/l for citrate, both lower than the measured values in samples. Identification of increased glyoxylic (oxoa cetic acid) and glyceric acids (2,3-dihydroxy propanoic) are also included to facilitate the diagnosis. (C) 2001 Elsevier Science B.V. All rights rese rved.