An All-Solid-State Silicate Ion-Selective Electrode Using PbSiO3 as a Sensitive Membrane

摘要

Ion-Selective Electrode (ISE) is an emerging technology for in situ monitoring of the chemical concentrations of an aqueous environment. In this work, we reported a novel all-solid-state silicate ISE, using an Ag/Pb/PbSiO3 electrode. This electrode responded to aqueous SiO3²⁻ with a reasonable slope of −31.34 mV/decade and a good reproductivity. The linear range covered from 10⁻⁵ M to 10⁻¹ M, for the Na2SiO3 solutions and the response time was generally less than 5 s. Its potentiometric response to pH and silicate indicated that the prepared electrode was sensitive to silicate, rather than pH. Compared to the traditional liquid ISE, our all-solid-state silicate electrode was resistant to high pressure and could be used in situ, in deep water. In addition, the miniaturized electrodes (diameter of 0.4 mm and a length of 2–3 cm) could be easily integrated into a multi-modal sensor, which could simultaneously determine multiple parameters. Our prepared silicate ISE could potentially be used to determine the presence of silicate in a low-chloride aqueous environment, where the ISE exhibited better selectivity for silicate, over interfering ions such as, SO4²⁻, NO3⁻, CH3COO⁻, CO3²⁻, and PO4³⁻.