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Electrochemical oxidation of cysteine at a film gold modified carbon fiber microelectrode its application in a flow-through voltammetric sensor.

Wang LH, Huang WS - Sensors (Basel) (2012)

Bottom Line: The possible reaction mechanism of the oxidation process is described from the relations to scan rate, peak potentials and currents.For the pulse mode, and measurements with suitable experimental parameters, a linear concentration from 0.5 to 5.0 mg·L(-1) was found.The limit of quantification for cysteine was below 60 ng·mL(-1).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Chemistry, Chia Nan University of Pharmacy and Science, Tainan, Taiwan. e201466.wang@msa.hinet.net

ABSTRACT
A flow-electrolytical cell containing a strand of micro Au modified carbon fiber electrodes (CFE) has been designedand characterized for use in a voltammatric detector for detecting cysteine using high-performance liquid chromatography. Cysteine is more efficiently electrochemical oxidized on a Au /CFE than a bare gold and carbon fiber electrode. The possible reaction mechanism of the oxidation process is described from the relations to scan rate, peak potentials and currents. For the pulse mode, and measurements with suitable experimental parameters, a linear concentration from 0.5 to 5.0 mg·L(-1) was found. The limit of quantification for cysteine was below 60 ng·mL(-1).

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Scanning electron micrographs (at 2 kV) of a Au-coated carbon fibre composite surface. (a) un-coated; (b) Au deposits (1 mM) 480 s; in 0.1 M perchloric acid (c) Au deposits (1 mM) 480 s; in 0.1 M acetate buffer (pH 5.02).
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f8-sensors-12-03562: Scanning electron micrographs (at 2 kV) of a Au-coated carbon fibre composite surface. (a) un-coated; (b) Au deposits (1 mM) 480 s; in 0.1 M perchloric acid (c) Au deposits (1 mM) 480 s; in 0.1 M acetate buffer (pH 5.02).

Mentions: The nature of the deposition conditions primarily affects the specific surface area of the gold catalyst. The optimum conditions for electrochemical deposition of gold have been investigated. The effects of the gold layer were performed by coating the CFE in deposition solution with different times (240–540 s). Electrochemical deposition of Au film on a CFE was achieved in 0.1 M perchloric acid and 0.1 M acetate aqueous solution of 4.0 mM of HAuCl4 by repeated potential scan between −1.0 V and +1.0 V (vs. Ag/AgCl) (at 100 mV/s), respectively. For comparision of the modified electrode substances, three scanning electron microscope pictures (SEM, JEOL Co.JXA-840) are shown in Figure 8. The Figure 8(a) presents an un-coated carbon fiber i.d. 7.54 μm. As shown in Figure 8(c), gold spherical particles were distributed more uniformly in acetate buffer than the percholic acid (Figure 8(b)).


Electrochemical oxidation of cysteine at a film gold modified carbon fiber microelectrode its application in a flow-through voltammetric sensor.

Wang LH, Huang WS - Sensors (Basel) (2012)

Scanning electron micrographs (at 2 kV) of a Au-coated carbon fibre composite surface. (a) un-coated; (b) Au deposits (1 mM) 480 s; in 0.1 M perchloric acid (c) Au deposits (1 mM) 480 s; in 0.1 M acetate buffer (pH 5.02).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376634&req=5

f8-sensors-12-03562: Scanning electron micrographs (at 2 kV) of a Au-coated carbon fibre composite surface. (a) un-coated; (b) Au deposits (1 mM) 480 s; in 0.1 M perchloric acid (c) Au deposits (1 mM) 480 s; in 0.1 M acetate buffer (pH 5.02).
Mentions: The nature of the deposition conditions primarily affects the specific surface area of the gold catalyst. The optimum conditions for electrochemical deposition of gold have been investigated. The effects of the gold layer were performed by coating the CFE in deposition solution with different times (240–540 s). Electrochemical deposition of Au film on a CFE was achieved in 0.1 M perchloric acid and 0.1 M acetate aqueous solution of 4.0 mM of HAuCl4 by repeated potential scan between −1.0 V and +1.0 V (vs. Ag/AgCl) (at 100 mV/s), respectively. For comparision of the modified electrode substances, three scanning electron microscope pictures (SEM, JEOL Co.JXA-840) are shown in Figure 8. The Figure 8(a) presents an un-coated carbon fiber i.d. 7.54 μm. As shown in Figure 8(c), gold spherical particles were distributed more uniformly in acetate buffer than the percholic acid (Figure 8(b)).

Bottom Line: The possible reaction mechanism of the oxidation process is described from the relations to scan rate, peak potentials and currents.For the pulse mode, and measurements with suitable experimental parameters, a linear concentration from 0.5 to 5.0 mg·L(-1) was found.The limit of quantification for cysteine was below 60 ng·mL(-1).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Chemistry, Chia Nan University of Pharmacy and Science, Tainan, Taiwan. e201466.wang@msa.hinet.net

ABSTRACT
A flow-electrolytical cell containing a strand of micro Au modified carbon fiber electrodes (CFE) has been designedand characterized for use in a voltammatric detector for detecting cysteine using high-performance liquid chromatography. Cysteine is more efficiently electrochemical oxidized on a Au /CFE than a bare gold and carbon fiber electrode. The possible reaction mechanism of the oxidation process is described from the relations to scan rate, peak potentials and currents. For the pulse mode, and measurements with suitable experimental parameters, a linear concentration from 0.5 to 5.0 mg·L(-1) was found. The limit of quantification for cysteine was below 60 ng·mL(-1).

Show MeSH