A new derivatization method for the determination of valproic acid in serum using tetramethylammonium hydroxide as a catalyst.

Valproic acid (VPA) pharmacokinetics is highly variable and monitoring of blood levels is necessary to determine its appropriate dosage. This study aimed to establish and validate a novel derivatization method for the determination of VPA. The method was based on the catalytic effect of tetramethylammonium hydroxide using 2,4'-dibromoacetophenone as a derivatization reagent. After derivatization, samples were injected into the HPLC system for analysis. The method showed a good linearity in the range of 1.0-200.7 μg mL-1 , and the limit of quantification was 1 μg mL-1 . All values of the accuracy and relative standard deviations were acceptable for the analyses of biological samples. The recoveries were in the range from 91.6 to 97.4% for VPA with RSD <3.9%. A novel and high conversion-rate derivatization method has been developed and validated for the determination of VPA in human serum. It can be applied to the analysis of VPA in clinic serum samples.