Coated wire lead(II)-selective electrode based on a Schiff base ionophore for low concentration measurements

Abstract

A synthesized Schiff base ligand was studied to characterize its ability as a cation carrier in a poly(vinyl chloride) (PVC) membrane coated wire electrode. The constructed coated wire electrode showed excellent response characteristics to lead(II) ions. The electrode exhibits Nernstian slope of 29.1 mV/decade at 20 °C over a wide concentration range of Pb2+ ions from 1.5 × 10−6 to 1.3 × 10−1 M with a low detection limit of 9.0 × 10−7 M. The proposed potentiometric sensor has the following advantages: a very fast response, high reproducibility, long lifetime, and, most importantly, good selectivities relative to a wide variety of other cations. The selectivity behavior of the proposed Pb2+-selective electrode revealed a considerable improvement compared with the previously reported PVC membrane electrodes for lead(II) ions. The potentiometric response of the electrode is independent of the pH of the test solution in the pH range 3.5–7.5. The performance of the proposed electrode was investigated in partially non-aqueous media. The electrode was successfully applied to determine Pb2+ ions in mineral water, blood serum, and alloy samples.