Highly selective potentiometric determination of mercury(II) ions using 1-furan-2-yl-4-(4-nitrophenyl)-2-phenyl-5H-imidazole-3-oxide based membrane electrodes.

The electrode characteristics and selectivities of PVC-based mercury(II) selective coated graphite electrode (CGE) and polymeric membrane electrode (PME) incorporating the recently synthesized 1-furan-2-yl-4-(4-nitrophenyl)-2-phenyl-5H-imidazole-3-oxide are reported here. The electrodes exhibit Nernstian slope for mercury(II) ions over wide concentration ranges, i.e. 1.0 x 10(-1)M to 1.0 x 10(-6)M (with CGE) and 1.0 x 10(-1)M to 1.0 x 10(-5)M (with PME). The lower detection limits shown by CGE and PME are 8.91 x 10(-7)M and 6.30 x 10(-6)M, respectively, in the pH range of 1.0-4.0. From the comparative study of these electrodes, CGE has been found to be better than PME in terms of lower detection limit and better selectivity for mercury(II) ions with comparatively less interference from silver(I) ions. The proposed electrodes can be successfully used as an indicator electrode for potentiometric titration of mercury with potassium dichromate. The electrodes have been successfully applied for estimation of mercury content in synthetic water samples, insecticide (parad tablet) and dental amalgam.