Potentiometric determination of La (III) using chitosan modified carbon paste electrode in line with the chemometrical methodology

Lanthanum (La3+) is a significant matter costly utilized in many industries, such as the usage in visual glass, ceramic, cracking catalysts of petrol, polishing materials, and the steel industries to remove sulfur, carbon, and other electronegative elements[1]. Potentiometric sensors with significant sensitivity, reproducibility, portability rather than other instrumentations analysis procedure have been as a cheap and simple analytical procedure [2-5].In this work, A D-optimal mixture design was applied as an experimental design strategy in order to screen and optimize the influence of composition of carbon paste on the electrode performance. Also, For the first time, chitosan was offered as a ligand for the determination of La (III) with the carbon paste electrode. Furthermore, MWCNT was used for increasing the electrode response to La (III). The good conductivity of MWCNT helps to the electron transformation in the carbon paste electrodes. The quadratic fitting pattern based on D-optimal model was used to find the desirability functions of the suggested design in order to assessment cross-interferences and the interactions between factors. In the optimal conditions obtained from experimental design, the fabricated sensor for determining of La (III) ions demonstrated a maximum Nernstian slope equal to 19.9 mVdecade-1 along a linear range from 1×10−5 to 1×10−2 mol.L−1 and detection limit of 1.37×10−6 mol.L-1. The designed sensor was successfully tested in the pH range of 3-8 and suitable selectivity, fast response time and long lifetime was obtained without any deviation. The offered electrode was used successfully as an indicator in the potentiometric titration of La (III) with EDTA.