[Determination of valproic acid level in serum by high performance liquid chromatography]

A method for the determination of valproic acid level in serum with high performance liquid chromatography was established. The conditions were Zorbax ODS (250 mm x 4.6 mm, 5 microns) column, 0.8 mL/min sulfuric acid solution (pH 4.2) eluent and UV-210 nm detector. The linear range was 0.82 mumol/L to 1.8 mumol/L (r = 0.996) and the detection limit was 0.82 mumol/L. The average recovery was 98.32% +/- 2.27% and the coefficients of variation were 3.31% (n = 5) and 4.82% (n = 7) for within-day and day-to-day tests respectively. This direct method was compared with the derivatization method.