2,4,6-triphenylpyrylium ion encapsulated into zeolite Y as a selective electrode for the electrochemical determination of dopamine in the presence of ascorbic acid.
2,4,6-Triphenylpyrylium ion immobilized inside the supercages of zeolite Y enhances by 1-2 orders of magnitude the response of electrochemical oxidation of dopamine in neutral aqueous media accompanied by a remarkable inhibition of post-electron-transfer reactions. The negative charge of the zeolite framework in which the 2,4,6-triphenylpyrylium ion is incorporated blocks the electrochemical oxidation of the negative ascorbate ion, enabling the determination of micromolar concentrations of dopamine in the presence of a large excess (10(3)-10(4) times) of ascorbate in phosphate buffer (pH 7.4). Under optimized conditions, linear calibration plots were obtained for a differential pulse detection mode over the range 250-1 microM dopamine with a sensitivity of 62 nA/microM and a detection limit (S/N = 3) of 0.2 microM in the presence of 1.0 mM ascorbate.
Doménech
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A
Department of Analytical Chemistry, University of Valencia, Burjasot, Spain. antonio.domenech@uv.es
García
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H
Doménech-Carbó
M T
MT
Galletero
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MS
D001205:Ascorbic Acid; D002138:Calibration; D004298:Dopamine / Q000032:analysis* / Q000378:metabolism; D004563:Electrochemistry / Q000592:standards; D004566:Electrodes / Q000592:standards; D010084:Oxidation-Reduction; D011714:Pyrans / Q000737:chemistry; D012680:Sensitivity and Specificity; D017641:Zeolites
D011714:Pyrans; D017641:Zeolites; D001205:Ascorbic Acid; D004298:Dopamine