Evaluation of electroanalytical sensing condition for membrane-based biosensor
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Date
2019-06
Authors
Sharmaine Binti Shahibullah
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Abstract
A simple evaluation on electroanalytical sensing condition for the determination of ascorbic acid using modified biosensor is described. The morphology and composition for the porous nylon membrane and electrochemical properties of assembled membrane-based biosensor were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The results confirmed that nylon-6 membrane has spherulites with uniform diameters and lengths. As for the sensing application, scan rate effect were studied by testing the samples containing phosphate buffer solution (PBS) and 20mM of ascorbic acid in PBS. A higher scan rate (50mV/s) was found to provide scanning curve in detection of analyte. The biosensor also showed an optimum response at pH 7.0 of PBS. Nylon-6 membrane were also assembled on carbon electrode or glassy carbon electrode hence electrochemical performances were observed by using different types of working electrodes, includes bare carbon electron, modified nylon-6/carbon electrode, bare glassy carbon electrode, modified nylon-6/carbon electrode and graphite. The highest intensity and peak current was observed when using graphite as the working electrode. The charge transfer resistance for each type of electrodes were analysed through EIS at different pH. Graphite showed to have the highest Ret value, means better to be used to detect ascorbic acid.