%0 Journal Article %T Simultaneous Determination of Trace Amounts Ascorbic Acid, Melatonin and Tryptophan using Modified Glassy Carbon Electrode Based on Cuo-CeO2-rGO-MWCNTS Nanocomposites %J Analytical and Bioanalytical Electrochemistry %I Analytical and Bioanalytical Electrochemistry is an international scientific journal, which is published online every 3 months (since 2009), every 2 months (since 2011) and monthly (since 2018) by Center of Excellence in Electrochemistry, University of Tehran %Z - %A Faridan, Ashkan %A Bahmaei, Manochehr %A Mehrdad Sharif, Amirabdolah %D 2022 %\ 02/28/2022 %V 14 %N 2 %P 201-215 %! Simultaneous Determination of Trace Amounts Ascorbic Acid, Melatonin and Tryptophan using Modified Glassy Carbon Electrode Based on Cuo-CeO2-rGO-MWCNTS Nanocomposites %K Ascorbic acid %K Melatonin %K Tryptophan %K Glassy carbon electrode %K Real sample %K Voltammetry %R %X In the presented study, for the first time, simultaneous electrochemical measurements of ascorbic acid (AA), melatonin (Mel), and tryptophan (Trp) were discussed. The CuO-CeO2-rGO-MWCNTs nanocomposite was prepared, then applied for amendment of glassy carbon electrode (GCE) surface to the measurement of target analytes using differential pulse voltammetry (DPV) technique. Electrical impedance spectroscopy (EIS) techniques displayed that CuO-CeO2-rGO-MWCNTs/GCE has the lowest electron transfer resistance (Rct) in comparison to GCE and was suitable for electrochemical applications. The synthesized compounds were analyzed by powerful methods including Scanning Electron Microscopy (SEM) and, X-ray Diffraction (XRD). At the CuO-CeO2-rGO-MWCNTs/GCE, three oxidation peaks appeared at 0.309, 0.631, and 0.855 V for AA, Mel, and Trp and the peaks separation of ΔEp (AA and Mel)=322 mV, and ΔEp (Mel and Trp)=224 mV in the electrochemical potential window of 0.0-1.1 V. In optimum DPV condition and pH=5.0, a dynamic range of AA (0.01-28 µM), Mel (0.01-12.6 µM) and Trp (0.01-13.5 µM) with the detection limit of 9, 8 and 7.3 nM for AA, Mel, and Trp, respectively, were acquired. The provided modified electrode was successfully used to monitor the analytes in human biological fluids. %U https://www.abechem.com/article_249819_6fbf6cc9ca85e2cef7689b60ac18a818.pdf