Abstract
A promising electrochemical sensor was developed using carbon paste electrode, gold nanoparticles and Nafion. This sensor is sensitive for the determination of catecholamine compounds, namely dopamine (DA), epinephrine (EP), L-norepinephrine (NP), and L-DOPA, as well as serotonin (5-TH), in the presence of interference molecules such as uric acid (UA) and ascorbic acid (AA). Cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy were used to verify the behavior of the studied compounds in the physiological pH of the body. Simultaneous determinations of DA with 5-TH and L-DOPA with acetaminophen (ACOP) give very good peak separations. The linear response was obtained for L-DOPA in the ranges of 2.0x10(-7) to 2.0x10(-5) mol L-1 with correlation coefficient 0.9990 and a second range of 5.0x10(-5) to 3.0x10(-3) mol L-1 with correlation coefficient 0.9985. LOD was found to be 1.45 x 10(-9) mol L-1 and 2.84 x 10(-6) mol L-1, respectively. The utility of this modified electrode was demonstrated for the determination of L-DOPA in human urine. (C) 2012 The Electrochemical Society. [DOI:10.1149/2.004210jes] All rights reserved.