Room Temperature Ionic Liquid/Multiwalled Carbon Nanotube/Chitosan-Modified Glassy Carbon Electrode as a Sensor for Simultaneous Determination of Ascorbic Acid, Uric Acid, Acetaminophen, and Mefenamic Acid

A room temperature ionic liquid (RTIL), multiwalled carbon nanotube (MWCNTs) and chitosan (CHIT)-modified glassy carbon electrode (RTIL-MWCNTs-CHIT/GCE) is fabricated and the electrochemical behaviors of ascorbic acid (ASC), uric acid (URI), acetaminophen (ACT), and mefenamic acid (MEF) are investigated using cyclic voltammetry (CV), chrono amperometry (CA), and differential pulse voltammetry (DPV) as diagnostic techniques. Electrochemical studies suggest that the RTIL and MWCNTs provide a synergistic augmentation that can increase current responses by improvement of electron transfers of these compounds on the electrode surface. The presence of the CHIT in the modified electrode can enhance the repeatability of the sensor by its antifouling effect and leads to the oxidation peak of URI shifts to less positive potentials and leads to more current peak separation between URI and ACT. Application of the DPV method shows that the linear calibration curves of ASC, URI, ACT, and MEF are obtained in the range of 4.0 × 10-5 to 4.0 × 10-3 mol L-1, 2.0 × 10-6 to 4.5 × 10-4 mol L-1, 1.0 × 10-6 to 4.0 × 10-4 mol L-1, and 2.0 × 10-6 to 6.5 × 10-4 mol L-1, respectively. Moreover, low cost and simplicity, wide linear range, good reproducibility, and stability are the important advantages of this modified electrode. The analytical performance of this sensor is evaluated for the detection of ASC, URI, ACT, and MEF in human serum and human urine with satisfactory results.