comparison of serum valproic acid determination through gas and high performance liquid chromatography methods

background valproic acid is widely used as an anticonvulsant and mood-stabilizing drug in the treatment of epilepsy. determination of serum valproic acid is required in epilepsy therapy for efficient control of seizures. objectives in the present study, the gas chromatography method was applied to determine serum valproic acid and resulting data were compared with those obtained by high performance liquid chromatography. materials and methods two methods were used: assayed patients' serum samples and serum quality control materials for laboratory diagnostics applied to high performance liquid chromatography (hplc)and gas chromatography (gc). all chemicals had a grade suitable for analysis. results the obtained results in both systems were in agreement regarding linearity, correlation and recovery. the results revealed a lower gc limit of quantification (8 µg/ml), a better intra-assay coefficient of variation (cv) (3.86% - 3.99%) and inter-assay cv (6.14% - 6.42%) for all three levels of control materials. in addition, a shorter run time of the gc vs. the hplc chromatographic step (6 minutes vs. 17 minutes) was observed. conclusions the present study reports a short run time of the chromatographic step as well as a good sensitivity for the gc method. furthermore, the significance of this method is the simplicity in sample preparation step without the need for derivatization and specific detector ensuring cost-effectiveness for the gc analysis. in summary, in comparison with hplc method, our obtained data illustrate a good performance of the gc analytical procedure and confirm its usefulness for the routine quantification of valproic acid level in patients' serum specimens.