Voltammetric Determination of Penicillin G in Sodium Dodecyl Sulfate/acetate Buffer Media on Glassy Carbon Electrode

Abstract

The presence of residues of penicillin in food products like milk and meat of animal origin exerts negative impact on public health such as drug resistance diseases and severe allergic responses. This work reports development of a simple voltammetric method for detection of penicillin using sodium dodecyl sulfate (SDS) in acetate buffer solution (ABS) on glassy carbon electrode. Addition of SDS to the penicillin G containing acetate buffer solution (ABS) was found to enhance the voltammetric oxidation current signal by about 5 times with insignificant shift of the oxidation potentials. Using cyclic voltammetry, the oxidation potentials for penicillin G were found to be 1.65V vs. Ag/AgCl in SDS/ABS, pH 4.5 and 1.60V vs. Ag/AgCl in ABS, pH 4.5. The diffusion coefficients for penicillin G were found to be 6.01x10^-7 cm²/sec and 1.39x10^-6 cm²/sec in ABS, pH 4.5 and SDS/ABS, pH 4.5 respectively. Linear concentration range were also investigated using square wave voltammetry and found to lie in the range of 1.25 – 15µM penicillin G in SDS/ABS, pH 4.5 and 2.5 – 10µM penicillin G in ABS, pH 4.5.

Limits of detection were also found to be 1.25µM and 2.5µM penicillin G in SDS/ABS, pH 4.5 and ABS, pH 4.5 respectively while limits of quantitation were 3.75µM penicillin G in SDS/ABS, pH 4.5 and 7.5µM penicillin G in ABS, pH 4.5. Possible interferants like Na⁺, K⁺, Zn²⁺, Ca²⁺, Fe³⁺, Cl^-, NO₃^-, PO₄^3- and SO₄^2- did not have any significant effect on the anodic currents and oxidation potentials of the penicillin G. These results show that the developed method is sensitive enough for use in the analysis of penicillin G in diverse real samples.