Square Wave Voltammetric Determination of Penicillin V in Sodium Dodecyl Sulfate Containing Media on Glassy Carbon Electrode

Abstract

The effect of adding sodium dodecyl sulfate (SDS), a surface-active agent to acetate buffer solution containing penicillin V was investigated. The voltammetric responses of penicillin V on glassy carbon electrode was a function of the concentration of penicillin V, surfactant and pH. Addition of SDS to the penicillin V containing acetate buffer solution (ABS) was found to enhance the voltammetric oxidation current signal by about 10 times with insignificant shift of the oxidation potentials. With this electrochemical method, the optimal pH and SDS concentration were found to be pH 4.5 and 0.347M respectively. Using cyclic voltammetry, the oxidation potential for penicillin V were found to be 1.61V vs. Ag/AgCl in SDS/ABS, pH 4.5 and 1.55V vs. Ag/AgCl in ABS, pH 4.5. Linear concentration range were also investigated using square wave voltammetry and found to lie in the range of 0.04 – 34.6µM penicillin V in SDS/ABS, pH 4.5 and 3.5 – 14.0µM penicillin V in ABS, pH 4.5. Limits of detection were also found to be 0.04µM penicillin V in SDS/ABS, pH 4.5 and 3.5µM penicillin V in ABS, pH 4.5 and limits of quantitation were 0.12µM penicillin V in SDS/ABS, pH 4.5 and 14µM penicillin V in ABS, pH 4.5.

Foreign substances like Na⁺, K⁺, Mg²⁺, Zn²⁺, Ca²⁺, Fe³⁺, Cu²⁺, Cl^-, NO₃^-, PO₄^3- and SO₄^2- did not have any significant effect on the voltammetric currents of penicillin V. These results confirm that this electrochemical method is sensitive enough to be used in the determination of penicillin V in diverse environmental and clinical samples.