Perchlorate selective membrane electrodes based on synthesized platinum(II) complexes for low-level concentration measurements

Three synthesized platinum(II) complexes, [PtR2(NN)] (R = Me, p-MeC6H4 and p-MeOC6H4; NN = 2,2′-bipyridyl), were studied to characterize their ability as an anion carrier in a PVC membrane electrode. The polymeric membrane electrodes (PME) and also coated glassy carbon electrodes (CGCE) prepared with [Pt(p-MeOC6H4)2(NN)] showed excellent response characteristics to perchlorate ions. The electrodes exhibited Nernstian responses to ClO4− ions over a wide concentration range from 5 × 10−7 to 4.0 × 10−1 M for PME and 1.5 × 10−7 to 2.7 × 10−1 M for CGCE with low detection limits (4.0 × 10−7 M for PME and 1.0 × 10−7 M for CGCE). The electrodes possess fast response time, satisfactory reproducibility, appropriate lifetime and, most importantly, good selectivity toward ClO4− relative to a variety of other common anions. The potentiometric response of the electrodes is independent of the pH of the test solution in the pH range 2.5–9.5. The proposed sensors were used in potentiometric determination of perchlorate ions in mineral water, urine samples and also samples containing interfering anions. The interaction of the ionophore with perchlorate ions was shown by UV–vis spectroscopy.