Synthesis of a Novel [diresorcinate-1,10-phenanthrolinecobalt(II)] Complex, and Potentiodynamic Fabrication of Poly(DHRPCo)/GCE for Selective Square Wave Voltammetric Determination of Procaine Penicillin G in Pharmaceutical and Biological Fluid Samples

This work presents synthesis, and characterization of a novel [diresorcinate-1,10-phenanthrolinecobalt(II)] (DHRPCo) complex, and potentiodynamic fabrication of poly(DHRPCo)/GCE for SWV determination of procaine penicillin G (ProPenG) in various pharmaceutical and biological samples. While UV-Vis and FT-IR results demonstrated stepwise synthesis of DHRPCo, the CV and EIS results evidenced modification of the surface of GCE by an electroactive polymer film that improved electrode surface area. In contrast to the peak of ProPenG at the unmodified electrode, an irreversible oxidative peak at poly(DHRPCo)/GCE with lower potential and six folds of current enhancement observed, that confirmed electrocatalytic effect of the polymer, SWV response of poly(DHRPCo)/GCE showed linear dependence on concentration of ProPenG in the range 0.1–200 μM, with LoD of 4.9 nM. Spike recovery results in various pharmaceutical and biological samples in the range 98.03–106.50 %, interference recovery in the presence of selected potential interferents at their various levels with associated errors under 3.39 %, and stability of the modifier with analysis time validated the method for determination of ProPenG. Poly(DHRPCo)/GCE was applied for determination of ProPenG in three brands of injection pharmaceutical formulation, human urine, human blood serum, and cow's milk samples. While no ProPenG was detected in the human urine, serum, and cow's milk samples, detected ProPenG in the injection powder samples was within 96.1–101.3 % of company label. The developed method showed superior performance over recently reported methods making it an excellent candidate for determination of ProPenG in real samples.