Electrochemical sensor based on ZrO2/ionic liquid for ultrasensitive simultaneous determination of metoclopramide and paracetamol in biological fluids

Abstract A novel electrode, carbon paste electrode modified with a nanocomposite of zirconium dioxide nanoparticles and ionic liquid (ZrO 2 NP/IL/CPE), has been fabricated and used to determine both the paracetamol (PAR) and metoclopramide (MCP) mixture in bulk powder, pharmaceutical formulations, and biological fluids. Furthermore, it is the first reported method to determine the paracetamol in presence of its toxic impurities (i.e., p-aminophenol and p-chloroacetanilide) simultaneously. Square wave (SWV) and cyclic voltammetric (CV) techniques were used to investigate the effect of scan rate, concentration, and pH in order to optimize sensor’s response. The calibration curves were obtained in both low and wide concentration ranges from (0.1–200 nM) to (3.0–100.0 µM) for both drugs with limit of detection (LOD) as low as 28 and 29 pM and limit of quantification (LOQ) 93 and 97 pM for PAR and MCP, respectively. The proposed sensor was used to assess PAR, MCP, and paracetamol toxic impurities in human plasma, urine samples, and pharmaceutical formulations with satisfactory results showing a broad dynamic linear range from 100 pM to 100 µM with high sensitivity and good reproducibility. Graphical Abstract