Determination of Chromium(III) and Magnesium(II) Ions in Pharmacological and Real Water Samples using Potentiometric Sensors based on Chitosan Schiff base Derivative as Green and Sensitive Ionophore

In the study, novel and sensitive carbon paste electrodes (CPEs) developed for thepotentiometric measurement of Cr(III) and Mg(II) ions in pharmacological and water samples.CPEs as indicator electrodes were prepared from a mixture of four components, includinggraphite powder, paraffin oil, multi-walled carbon nanotubes (MWCNTs), and a greenionophore (Chitosan Schiff base derivative). Optimization of CPE composites indicated thatthe critical factor in the preparation of the CPEs was chitosan Schiff base derivative whichselectivity proposed sensors highly depended on this factor. Effects of various parameters suchas pH, lifetime, response time, and selectivity of the potentiometric sensors to determine Cr(III)and Mg(II) ions were also evaluated. The results indicated that the proposed sensors can beapplied in a relatively wide range of pH, long lifetimes, short response times, and excellentselectivity for the analyte determination. The prepared sensors show Nernstian slopes of 19.53and 29.83 mVdecade−1, and LODs of 5.6×10– 8 and 4.4×10−9 with RSDs lower than 2.3% forCr(III) and Mg(II) ion determination, respectively. The calibration curves were linear in theconcentration ranges of 1.0×10-7-1.0×10-2 and 1.0×10-8-1.0×10-3 M, and R-square of 0.989 and0.987 for the measurement of Cr(III) and Mg(II) ions, respectively. Besides, the sensors weresuccessfully utilized for the Cr(III) and Mg(II) ion measurement in real samples such as tabletand tap water samples with suitable recovery higher than 97.6%.