A validated potentiometric method for the rapid determination of chromium ions content in food samples using a portable graphite sensor

Abstract

Cr(III) has a vital role in the biological systems, and in many industrial and environmental processes, so the development of a selective, sensitive, and rapid method for its determination is a challenging goal. In this paper, an effective, selective, and inexpensive Cr(III) ions modified carbon paste electrode (MCPE) based on a simple ionophore named benazepril (BNZ) was developed and described. The proposed technique was validated using the EURACHEM guidelines. Our sensor shows a Nernstian slope of 19.20 ± 0.39 mV/decade in the range of 8.0 × 10^-6-1.0 × 10^-1 mol L^-1with a quick response time (10 s) and can be applied for the measurements for at least 54 days with negligible change in the results. The proposed sensor has a stable potentiometric response in the pH range of 2.5-6.5 and has great selectivity towards Cr(III) ions over numerous inorganic cations. The Cr(III)-BNZ surface interaction was scrutinized by a scanning electron microscope (SEM). Lastly, the proposed electrode was applied for the determination of Cr(III) ions in various food samples, and the results were compared with the results of the inductively coupled plasma-optical emission spectroscopy (ICP-OES).

Keywords: Chromium; Potentiometry; Sensor; Simple ionophore.