Surface manipulation for improving the sensitivity and selectivity of glassy carbon electrodes by electrochemical treatment.
The performance of electrochemical sensor is related to the surface structure of electrode. Electrochemical treatment was often used to improve the performance of glassy carbon electrodes (GCEs) for the simplicity of operation. The densely compact oxide film formed on the surface of the electro-oxidized glassy carbon electrodes (GCEs-ox) could be changed to be porous by following electro-reduction of the GCEs-ox obtaining the totally reduced GCEs-ox (GCEs-re). The GCEs-re with a porous film exhibited high sensitivity in detecting epinephrine (EP) accompanying with poor stability and incapability of anti-interference from negatively charged ascorbic acid (AA) because both of AA and EP could permeate the porous film. Compared to the GCEs-re, the GCEs-ox with a densely compact film displayed relatively lower sensitivity but higher stability. To combine the advantages of both porous and densely compact oxide films, a partially reduced GCE-ox (GCE-ox-re) with an oxide film porous outer and densely compact inner was designed by controlling the electro-reduction time and potential, which will provide a new strategy for improving the performance of GCEs. The GCEs-ox-re exhibited high sensitivity, excellent stability and high selectivity in the detection of EP. In the presence of 0.1 mM AA, the anodic peak current of EP was directly proportional to its concentration in the range of 8.0x10(-9)-2.0x10(-7) M and EP as low as 2.0x10(-9) M could be detected.
Zhao
Qiao-Ling
QL
College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, Key Laboratory of Analytical Chemistry for Biology and Medicine, Ministry of Education, Wuhan University, Wuhan 430072, PR China.
Bao
Lei
L
Luo
Qing-Ying
QY
Zhang
Min
M
Lin
Yi
Y
Pang
Dai-Wen
DW
Zhang
Zhi-Ling
ZL
D001205:Ascorbic Acid / Q000032:analysis; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D002244:Carbon; D055664:Electrochemical Techniques; D004566:Electrodes; D004837:Epinephrine / Q000032:analysis; D005898:Glass; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D013499:Surface Properties
D002244:Carbon; D001205:Ascorbic Acid; D004837:Epinephrine