COVID-19 chloroquine drug detection using novel, highly sensitive SnO2-based electrochemical sensor

Abstract

A highly sensitive, selective, stable, and cost-effective SnO2-based electrochemical sensor is reported for the detection of chloroquine phosphate (CQP). Hydrothermal synthesis is used to synthesize SnO2 nanoparticles, which are mixed with graphite and form a highly electrochemically active composite. The SnO2 nanoparticles and SnO2/graphite composite are fully characterized physico- and electrochemically. Using the optimal SnO2/graphite composite, an excellent analytical performance is demonstrated with an electrode sensitivity of 35.7 µA/µM.cm2, a linear range of 0.1–23.3 µM, and limits of detection and quantification of 0.01 µM and 0.04 µM, respectively. High CQP selectivity with minimal interference at 100 × concentration of interferents is shown. The sensor is also highly repeatable and reproducible with RSD of 2.46 % and 1.86 %, respectively, and can retain > 85 % of its activity upon storage. The validity of the new sensor for real sample analysis is shown by applying it to CQP tablets using the standard addition method, obtaining an excellent percentage recovery of ∼ 102 %. The low cost, facile processing, and superior performance of the SnO2/graphite electrode make it an up-and-coming candidate for the commercial electrochemical detection of CQP and other small molecules.