Development of a potentiometric sensor for dihydrogen arsenite ion determinationin environmental samples employing a simplex lattice mixture design

Abstract

ABSTRACT Arsenic is a widely utilised element in various industries that this element and its species have high toxicity even at very low concentrations. We introduced a potentiometric sensor using a carbon paste electrode (CPE) as an indicator electrode for the dihydrogen arsenite ion determination in environmental samples. A synthetic Schiff base was chosen as an ionophorein the CPE composite, showing a high affinity towards the dihydrogen arsenite ions as analyte. Using theSchiff baseas a suitable ionophore leads to a suitable selectivity for determining the dihydrogen arsenite ion in the presence of various interfering species. Besides, paraffin oil as a binder, multi-walled carbon nanotubes (MWCNTs), graphite powder were utilized as other CPE components. In this procedure, a robust experimental designbased on the simplex lattice mixture design was applied for optimising the carbon paste electrode composition. The potentiometric sensor has a linear response in the concentration range of 4.3 × 10−8-1.0 × 10−2mol L−1 and a reasonable Nernstian slope of 59.429 mV decade−1 with an R2 of 0.9917 for the dihydrogen arsenite ion determination. Various environmental samples, including tap water, river water and mineral water samples, were analysed by the sensor, showing appropriate RSD and recoveries for the dihydrogen arsenite ion measurement. The sensor’s advantages include the simple and straightforward CPE preparation, simple operation, high lifetime, fast response time, wide linearity, high selectivity, and low detection limit for determining the dihydrogen arsenite ions.