Detection of Ascorbic acid in the Interference of Dopamine and Uric acid using Graphene Oxide and Amino Serine

Ascorbic acid (AA) is an essential nutrient playing an important role in human body. In human plasma, AA generally coexists with dopamine (DA) and uric acid (UA) and their electrochemical potentials are typically superposed and indistinguishable. So, it is impossible to detect AA precisely in the solution contained DA and UA. In this research, serine (SER) and graphene oxide (GO) were used for detecting AA in the interference of DA and UA through differential pulse voltammetry. The GO/SPE was prepared by coating GO on the working electrode (WE) of a screen-printed electrode (SPE). The GO/SPE was then modified with SER using cyclic voltammetry of GO/SPE in SER solution for ten cycles to obtain SER-GO/SPE. Physical and electrochemical properties of GO/SPE and SER-GO/SPE were analyzed by scanning electron microscopy and electrochemical impedance spectroscopy. The voltammetry results showed that SER-GO/SPE was able to separate the oxidation peak potentials of AA, DA and UA into three well-defined peaks at 50.57 mV, 365.73 mV and 524.55 mV, respectively. The calibration curve of AA detection in the presence of DA (50 μM) and UA (50 μM) was in a range of 0.08 -90 mM and the limit of detection (LOD) was 0.021 mM. The proposed technique may be useful for the detection of ascorbic acid in various fields, including medical diagnostic and food industry.