Imprinted Polymer – Modified Hanging Mercury Drop Electrode for Differential Pulse Adsorptive Stripping Voltammetric Analysis of a Diquat Herbicide

An imprinted polymer modified hanging mercury drop electrode (HMDE) in Model 303A system in conjunction with a PAR Model 264A Polarographic Analyzer/Stripping Voltammeter has been used for the selective analysis of a diquat herbicide viz., 5,6-dihydropyrazino[1,2,3,4-[lmn]-1,10-phenanthrolinium dichlorides in differential pulse cathodic stripping voltammetry mode. Complex aqueous samples (drinking water and agricultural soil suspension), spiked with a diquat herbicide, were directly analyzed by the adsorptive accumulation of the analyte over the working electrode (accumulation potential −0.8 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0, supporting electrolyte 0.1 M KCl, scan rate 10 mV s−1, pulse amplitude 25 mV). The limit of detection for diquat herbicide was found to be 0.34 nmol L−1 (0.1 ppb, RSD 2%, S/N=2).