Highly sensitive and selective method to detect dopamine in the presence of ascorbic acid by a new polymeric composite film.
A new approach was applied to modify gold electrode with a unique polymer composite for selectively detecting dopamine (DA), a neurotransmitter, in the presence of an electroactive species of ascorbic acid (AA). After self-assembly of 11-mercaptoundecanoic acid (MUA) monolayer on gold surface, polyethylene glycol (PEG) was used to perform electrochemical esterification with MUA. In general, AA is the main interference of DA detection in a biological system. The resulting composite layer showed high sensitivity to detect DA but selectively blocked the interference from AA. Furthermore, for the first time, an interesting mechanism was demonstrated from our experimental results, namely, that the catalytic effect of AA on DA is limited by DA concentration when AA/DA>1. The modified electrode showed good reproducibility (+/-2% relative standard deviation), a low detection limit (10 nM), a fast response time (<2s), high sensitivity (86 nA/microM), a wide dynamic range of detection (20 microM), and great selectivity (without AA interference). The discovery is very promising for applications of detection of DA in a physiological environment where a high concentration of AA always exists.
Xiao
Yinghong
Y
School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore.
Guo
Chunxian
C
Li
Chang Ming
CM
Li
Yibin
Y
Zhang
Jun
J
Xue
Renhao
R
Zhang
Sam
S
D001205:Ascorbic Acid / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002138:Calibration; D004298:Dopamine / Q000032:analysis*; D004563:Electrochemistry; D005227:Fatty Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry
C505222:11-mercaptoundecanoic acid; D005227:Fatty Acids; D011108:Polymers; D013438:Sulfhydryl Compounds; D011092:Polyethylene Glycols; D006046:Gold; D001205:Ascorbic Acid; D004298:Dopamine