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

• Published in: Analytical chemistry (Washington) Vol. 74; no. 3; pp. 562 - 569
• Main Authors: Doménech, A, García, H, Doménech-Carbó, M. T, Galletero, M. S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.02.2002
• Subjects: Acids; Analysis; Analytical biochemistry: general aspects, technics, instrumentation; Analytical, structural and metabolic biochemistry; Ascorbic Acid; Biological and medical sciences; Calibration; Chemistry; Dopamine - analysis; Dopamine - metabolism; Electrochemistry - standards; Electrodes; Electrodes - standards; Fundamental and applied biological sciences. Psychology; Oxidation-Reduction; Pyrans - chemistry; Sensitivity and Specificity; Zeolites; Electrochemical method; Dopamine; Analysis method
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac010657i

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 (103−104 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 μM dopamine with a sensitivity of 62 nA/μM and a detection limit (S/N = 3) of 0.2 μM in the presence of 1.0 mM ascorbate.