Determination of Ascorbic Acid, Acetaminophen, and Caffeine in Urine, Blood Serum by Electrochemical Sensor Based on ZnO-Zn2SnO4-SnO2 Nanocomposite and Graphene
Elham Nikpanje, Manochehr Bahmaei, Amir Abdolah Mehrdad Sharif
Abstract
In the present research, a simple electrochemical sensor based on a carbon paste electrode (CPE) modified with ZnO-Zn 2 SnO 4 -SnO 2 and graphene (ZnO-Zn 2 SnO 4 -SnO 2 /Gr/CPE) was developed for the direct, simultaneous and individual electrochemical measurement of Acetaminophen (AC), Caffeine (Caf) and Ascorbic acid (AA). The synthesized nanomaterials 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-Zn 2 SnO 4 -SnO 2 /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 M 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 M for AA, AC and, Caf with the detection limit of 6.28, 3.64 and 3.85 nM, respectively. Besides, the ZnO-Zn 2 SnO 4 -SnO 2 /Gr/CPE shows an excellent selectivity, stability, repeatability, and reproducibility for the determination of AA, AC and, Caf. Finally, the proposed 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%.