Graphite paste electrode modified with Lewatit® FO36 nano-resin for simultaneous determination of ascorbic acid, acetaminophen and tryptophan

In this study, a novel graphite paste electrode (GPE) modified with Lewatit (R) FO36 resin (LFOR) for the simultaneous determination of ascorbic acid (AA), acetaminophen (AC) and tryptophan (Trp) is described. A detailed investigation by transmission electron microscopy and electrochemistry was performed in order to elucidate the preparation process and properties of the GPE/LFOR. The electrochemical response characteristics of the modified GPE/LFOR toward AA, AC and Trp were investigated by cyclic voltammetry, linear sweep voltammetry (LSV) and chronoamperometry. Under the optimum conditions, detection limits of 2.08 mu M, 0.842 mu M and 0.385 mu M were obtained for AA, AC and Trp, respectively. Some kinetic and thermodynamic parameters for the electrochemical oxidation of AA, AC and Trp, including electron transfer coefficients and diffusion coefficients, were also determined. LSV was used for the simultaneous determination of AA, AC and Trp at the modified electrode. Moreover, GPE/LFOR was successfully used to determine the concentrations of AA, AC and Trp in real samples.