Voltammetric study of pyridine-2-aldoxime methochloride at poly(p-toluene sulfonic acid) modified glassy carbon sensor and its analytical applications

Abstract

A poly(p-toluene sulfonic acid) (p-TSA) modified glassy carbon electrode (GCE) was fabricated by electropolymerisation using cyclic voltammetry (CV). This chemically modified electrode showed high stability, good selectivity and reproducibility for the determination of pyridine-2-aldoxime methochloride (PAM chloride) a cholinesterase reactivator, used in military as an antidote in the treatment of organophosphate poisoning and to counteract the effects of overdosage by anticholinesterases used in treating myasthenia gravis. Compared with bare GCE, the modified electrode showed an enhancement in the oxidation peak current as well as a reduction in the oxidation potential of PAM chloride. Favorable electrostatic interaction between the negatively charged poly(p-TSA) film and the positively charged drug as well as the formation of hydrogen bonds could contribute to this enhanced sensitivity. Under optimum conditions the oxidation peak current is proportional to the concentration of PAM chloride in the range 1 × 10⁻³ M to 1 × 10⁻⁷ M with a detection limit of 3 × 10⁻⁸ M. The developed sensor was also successfully applied for the determination of PAM chloride in body fluids.