Square wave voltammetric determination of valproic acid in pharmaceuticalPreparations

Abstract

The electrochemical behavior of valproic acid (VAL) was investigated using square wave voltammetry, cyclicvoltammetry, and sampled direct current polarography and a new square wave voltammetric method was developed fordetermination of VAL in pharmaceutical preparations. VAL showed two reduction peaks at about {0.2 V and {0.8 V vs.Ag/AgCl 3 M KCl with a hanging mercury drop electrode in 0.05 M pH 3.3 Britton{Robinson (BR) buffer. These peakswere named peak I and peak II, respectively. The types of limiting current of both peaks were determined as diffusioncontrolled based on cyclic voltammetry studies. A linear calibration graph was obtained in the range 1.46 104{1.0 103M. The limit of detection (LOD) and limit of quanti cation (LOQ) were 1.09 104M (21.05 g/mL) and1.10 104M (144.20 g/mL), respectively. Recovery studies for the accuracy of the method were performed byadding known amounts of VAL and it was found to be 109.67 4.85%. The proposed method was successfully appliedto pharmaceutical products on the market.