Authors: J. Fei, Y. Sun, S. Hu and Z. Gao
Affilation: Institute of Bioengineering and Nanotechnology, Singapore
Pages: 260 - 263
Keywords: carbon nanotube, electrode, ascorbic acid, determination
Sensitive and selective ascorbic acid biosensors were developed for the determination of ascorbic acid (AA) based on glassy carbon electrode (GCE) coated with a thin multi-wall carbon nanotube (MWNT) film. The MWNT film showed excellent electrocatalytic activity towards the oxidation of AA. In contrast to a bare GCE, the oxidation current of AA increased greatly and the oxidation potential of AA shifted negatively by as much as 460 mV to 0.018 V (vs. SCE) at the MWNT film modified GCE. Experimental variables, affecting the performance of the biosensors, such as the amount of MWNT on the GCE surface, solution composition, pH, electrocatalysis potential etc, were investigated. Under selected conditions, amperometric measurements were performed at an applied potential of 0.01 V. A linear response of AA was obtained in the range of 5.0 mM and 4.0 with a detection limit of 2.0 mM. The interferences studies indicated that the biosensors were highly selective to AA in a mixture of AA, acetaminophen, uric acid and dopamine. The proposed procedure was successfully applied to the determination of AA in pharmaceutical and food samples with little or no sample pretreatment.