Differential pulse adsorptive stripping voltammetric determination of benzocaine and butacaine with Nafion modified glassy carbon electrode

A sensitive, simple and accurate differential pulse adsorptive stripping voltammetric (DPAdSV) method for determination of benzocaine (BZE) and butacaine (BTE) using a nafion modified glassy carbon electrode (NMGCE) is described. NMGCE exhibited significantly increased sensitivity and selectivity for BZE and BTE compared to the bare glassy carbon electrode (GCE). Factors affecting peak currents, such as accumulation potential, accumulation time, presence of surfactants, buffer pH, etc. for the determination of BZE and BTE, were studied using DPAdSV. The modified electrode was less susceptible to peak depression than the bare electrode in the presence of surfactants and ascorbic acid. Peak currents showed a linear response in the concentration range 3.2 x 10(-9) to 4.5 x 10(-7) mol dm(-3) for BZE and 4.2 x 10(-9) to 3.6 x 10(-7) mol dm(-3) for BTE, with the respective limits of detection (LOD) of 2.4 x 10(-9) mol dm(-3) and 3.6 x 10(-9) mol dm(-3) at NMGCE. The method has been successfully applied for the determination of BZE and BTE in a spiked human urine sample. Repeatability and reproducibility of the proposed method were also studied.