Abstract
In this report, simultaneous electrochemical determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp) was achieved using buckyball-modified carbon ceramic microelectrodes (CCMEs). A concentration-dependent increase in anodic peak current signals was observed in comparison with those obtained at bare CCMEs. The optimal pH for simultaneous determination of a quaternary mixture of AA-DA-UA-Trp was determined to be pH 4. The peak separations for the mixture containing AA-DA-UA-Trp were well-defined at the scan rate of 50 mV s(-1). The catalytic peak current obtained was linearly dependent on the AA, DA, UA and Trp concentrations in the range of 6.0-600, 6.0-600, 6.0-600 and 4.0-440 μM, respectively. The detection limits for AA, DA, UA and Trp were also determined to be 1.64, 0.82, 0.36 and 1.22 μM, respectively. The analytical performance of this sensor has also been challenged for simultaneous electrochemical detection of AA, DA, UA and Trp in real samples.