Determination of cadmium(II) using a glassy carbon electrode modified with a Cd-ion imprinted polymer

This study reports design and synthesis of a cadmium(II)-selective electrode using cadmium (II) imprinted polymer nanoparticles (IIP-NPs) and uses the electrode for differential pulse voltammetry determination of cadmium ions. The IIP-NPs were prepared by co-precipitation polymerization of 4-vinylpyridine, ethylene glycol dimethacrylate, 2,2′-azobisisobutyronitrile, 2-aminobenzimidazole and cadmium ions, in acetonitrile solution. After polymerization, the Cd(II) ions were leached out of the polymer nanoparticles with dilute hydrochloric acid to provide some cavities for hosting Cd(II). Also, a glassy carbon electrode was modified with NIP-NPs and differential pulse stripping voltammetry was employed as a detection tool after open-circuit sorption of Cd(II) ions into the electrode and its reduction to Cd(0). A clear difference in response was observed between electrodes modified with IIP-NPs and those without IIP-NPs. The modified electrode responded to Cd(II) with a linear concentration ranges from 0.008 to 0.05 μM and in the ranges from 0.05 to 0.80 μM. The detection limit of the sensor for Cd(II) was 1 × 10−4 μM (at S/N = 3), while it was successfully applied to trace determination of Cd(II) in samples of spiked environmental water.