Determination of ascorbic acid, acetaminophen, and caffeine in urine, blood serum by electrochemical sensor based on zno-zn2sno4-sno2 nanocomposite and graphene

Abstract

In the present research, a simple electrochemical sensor based on a carbon paste electrode (CPE) modified with ZnO-Zn2 SnO4-SnO2 and graphene (ZnO-Zn2 SnO4-SnO2 /Gr/CPE) was developed for the direct, simultaneous and individual electrochemical measurement of Acetaminophen (AC), Caffeine (Caf) and Ascorbic acid (AA). The synthesized nano-materials were investigated using scanning electron microscopy, X-ray Diffraction, Fourier-transform infrared spectroscopy, and electrochemical impedance spectroscopy techniques. Cyclic voltammetry and differential pulse voltammetry were applied for electrochemical investigation ZnO-Zn2 SnO4-SnO2 /Gr/CPE, and the impact of scan rate and the concentration of H on the electrode’s responses were investigated. The voltammograms showed a linear relationship between the response of the electrode for individual oxidation of AA, AC and, Caf in the range of 0.021-120, 0.018-85.3, and 0.02-+ 97.51 μM with the detection limit of 8.94, 6.66 and 7.09 nM (S/N = 3), respectively. Also, the amperometric technique was applied for the measuring of the target molecules in the range of 0.013-16, 0.008-12 and, 0.01-14 µM for AA, AC and, Caf with the detection limit of 6.28, 3.64 and 3.85 nM, respectively. Besides, the ZnO-Zn2 SnO4-SnO2 /Gr/CPE shows an excellent selectivity, stability, repeatability, and reproducibility for the determination of AA, AC and, Caf. Finally, the pro-posed sensor was successfully used to show the amount of AA, AC and, Caf in urine, blood serum samples with recoveries ranging between 95.8% and 104.06%.