Fabrication of Chiral Poly(3,4-ethylenedioxythiophene) Derivatives Modified Glassy Carbon Electrodes for Ascorbic Acid Determination

We report the highly selective and sensitive voltammetric dopamine quantification in the presence of ascorbic acid and serotonin by using glassy carbon electrodes modified with a dispersion of multi-wall carbon nanotubes (MWCNT) in polyethylenimine, PEI (GCE/MWCNT-PEI). The electrocatalytic activity of the MWCNT deposited on the glassy carbon electrode has allowed an important decrease in the overvoltages for the oxidation of ascorbic acid and dopamine, making possible a clear definition of dopamine, serotonin and ascorbic acid oxidation processes. The sensitivities for dopamine in the presence and absence of 1.0 mM ascorbic acid and serotonin were (2.18±0.03 × 105 μAM−1 (r = 0.9998); and (2.10±0.07 × 105 μAM−1 (r = 0.9985), respectively, demonstrating the excellent performance of the GCE/MWCNT-PEI. The detection limit for dopamine in the mixture was 9.2 × 10−7 M. The R. S. D. for the determination of 50 μM dopamine using four different electrodes was 3.9% when modified with the same MWCNT/PEI dispersion, and 4.6% when using four different dispersions. The modified electrode has been successfully applied for recovery assays of dopamine in human blood serum. Therefore, the new sensor represents an interesting and promising alternative for the electrochemical quantification of neurotransmitters and other analytes of clinical interest.

Download Full-text

Novel choline and acetylcholine modified glassy carbon electrodes for simultaneous determination of dopamine, serotonin and ascorbic acid

Journal of Electroanalytical Chemistry ◽

10.1016/j.jelechem.2004.02.022 ◽

2004 ◽

Vol 569 (1) ◽

pp. 135-142 ◽

Cited By ~ 99

Author(s):

Guan-Ping Jin ◽

Xiang-Qin Lin ◽

Jing-ming Gong

Keyword(s):

Ascorbic Acid ◽

Simultaneous Determination ◽

Glassy Carbon ◽

Carbon Electrodes ◽

Glassy Carbon Electrodes

Download Full-text

Selective dopamine detection using aptamer-functionalized glassy carbon electrodes

Canadian Journal of Chemistry ◽

10.1139/cjc-2014-0444 ◽

2015 ◽

Vol 93 (5) ◽

pp. 572-577 ◽

Cited By ~ 7

Author(s):

Ryan Walsh ◽

Uyen Ho ◽

Xiao Li Wang ◽

Maria C. DeRosa

Keyword(s):

Ascorbic Acid ◽

Electrochemical Detection ◽

Glassy Carbon ◽

Dna Aptamer ◽

Carbon Electrodes ◽

Glassy Carbon Electrodes ◽

Organic Monolayer ◽

Dopamine Detection ◽

Redox Active ◽

Viable Approach

The electrochemical detection of dopamine using glassy carbon electrodes suffers from a lack of selectivity toward the neurotransmitter, as interferences such as other catechol-containing neurochemicals and ascorbic acid can be oxidized at overlapping potentials. Several approaches have been employed to improve the selectivity of these electrodes towards dopamine including electrochemical pretreatment and organic monolayer depositions. Here, we characterize glassy carbon electrodes that were initially passivated through a trifluoromethylphenyl and nitrophenyl monolayer deposition and then functionalized with a specific DNA dopamine aptamer. Passivation with the mixed monolayer cuts off all signals from the redox-active neurochemicals. After functionalization with the DNA aptamer, the dopamine signal is restored and the electrodes are more responsive to dopamine than to any other related catechol-containing compounds or other common neurochemicals such as ascorbic acid. Our findings indicate that aptamer functionalization of glassy carbon electrodes may provide a viable approach for tuning the selectivity of electrochemical detection.

Download Full-text