Determination of epinephrine in urine using multi-walled carbon nanotube modified with cobalt phthalocyanine in a paraffin composite electrode

Author(s)

Moraes, Fernando C. ^[1] ; Golinelli, Diego L. C. ^[2] ; Mascaro, Lucia H. ^[1] ; Machado, Sergio A. S. ^[2]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Quim, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: SENSORS AND ACTUATORS B-CHEMICAL; v. 148, n. 2, p. 492-497, JUL 15 2010.
• Web of Science Citations: 66

Abstract

This paper describes the development, electrochemical characterization and utilization of a cobalt phthalocyanine (CoPc), modified multi-walled carbon nanotube (MWCNT), and paraffin composite electrode for the quantitative determination of epinephrine (EP) in human urine samples. The electrochemical profile of the proposed composite electrode was analyzed by differential pulse voltammetry (DPV) that showed a shift of the oxidation peak potential of EP at 175 mV to less positive value, compared with a paraffin/graphite composite electrode without CoPc. DPV experiments in PBS at pH 6.0 were performed to determine EP without any previous step of extraction, clean-up, and derivatization, in the range from 1.33 to 5.50 mu mol L(-1), with a detection limit of 15.6 nmol L(-1) (2.86) of EP in electrolyte prepared with purified water. The lifetime of the proposed sensors was at least over 1000 determinations with 1.7 and 3.1 repeatability and reproducibility relative standard deviations, respectively. Human urine samples without any purification step were successfully analyzed under the standard addition method using paraffin/MWCNT/CoPc composite electrode. (C) 2010 Elsevier B.V. All rights reserved. (AU)