Amperometric ascorbic acid biosensors based on the oxygen and glassy carbon electrodes modified with ascorbate oxidase immobilized-silk fibroin/polyethylene glycol membrane

• Main Authors: Pacharawan Ratanasongtham, Lalida Shank, Jaroon Jakmunee, Ruangsri Watanesk, Surasak Watanesk
• Format: Journal
• Published: 2018
• Subjects: Biochemistry, Genetics and Molecular Biology; Chemistry; Materials Science; Mathematics; Agricultural and Biological Sciences; Arts and Humanities
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85030710645&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/43600
• Institution: Chiang Mai University

© 2017, Chiang Mai University. All rights reserved. Amperometric biosensors for the specific determination of ascorbic acid (AA) were developed by immobilizing ascorbate oxidase (ASOD) on a polyethylene glycol (PEG) modified silk fibroin (SF) membrane coupled to either the O 2 electrode or the glassy carbon electrode (GCE). Both the O2 electrode and the GCE modified with SF/PEG/ASOD displayed their best sensor response at the same optimum conditions (0.40 mg/L of ASOD in phosphate buffer, pH 5). By comparing the responses of both AA biosensors, the GCE based biosensor showed better linearity (r 2 = 0.999 in the range of 0.5-12.0 mM) with shorter response time (26 s) compared to the O 2 electrode based biosensor (r 2 = 0.997 in the range of 0.5-5.0 mM, response time 48 s). In addition, the GCE based biosensor exhibited better selectivity and had simpler preparation steps. However, both biosensors provided approximately the same sensitivity, but the O 2 electrode based biosensor had a longer storage time (0.703 mA.mM-1, 9 days) than the GCE based one (0.695 mA.m M-1 , 5 days). For both biosensors, there is little interference from citric acid, sodium chloride or ethanol, but some interference (2-4% error) from glucose.