Exploring pralidoxime chloride as a universal electrochemical probe for organophosphorus pesticides detection

An electrochemical method based on non-enzymatic inhibition for the determination of organophosphorus pesticide (OPPs) using pralidoxime chloride (PAM-Cl) as a universal electrochemical probe was reported. Cyclic voltammetry was performed to characterize the redox properties of pralidoxime and OPPs. Differential pulse voltammetry (DPV) was carried out to analyze the influence of anion (chloride and iodide ions), to optimize the pH of testing condition, and to explore the relationship between pralidoxime and OPPs. The results showed that iodide ion generated an anodic peak close to the peak of pralidoxime, which would interfere in the detection of OPPs. Phosphate buffer solution (pH 7.0) was chosen because of its high peak current and low peak potential when testing PAM-Cl by DPV. Chlorpyrifos, fenthion, and methyl parathion were examples of three existing OPPs detection methods. The peak current of PAM-Cl decreased along with the increase of concentration of OPPs in the solution. The limit of detection was 0.018 μM, 0.100 μM, and 0.215 μM, respectively. It was the first time for PAM-Cl to be used as a universal electrochemical probe to develop a simple, cheap and stable method for OPPs detection.