Barbituric acid sensor based on molecularly imprinted polymer-modified hanging mercury drop electrode

Abstract

A barbituric acid sensor based on molecularly imprinted polymer-modified hanging mercury drop electrode is reported for sensitive and selective analysis in aqueous and blood plasma samples. It was developed by coating directly the barbituric acid- imprinted polymer, which is prepared from melamine and chloranil, onto the surface of a hanging mercury drop electrode under charge-transfer interaction at +0.3 V (vs. Ag/AgCl) in Model 303A electrode system connected with a polarographic analyzer/stripping voltammeter (PAR Model 264A). The binding event of barbituric acid was detected in the imprinted polymer layer through differential pulse, cathodic stripping voltammetric (DPCSV) signal at optimized operational conditions [accumulation potential +0.3 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0 (without supporting electrolyte), scan rate 10 mV s-1, pulse amplitude 25 mV]. The limit of detection for barbituric acid was found to be 0.54 ppm (RSD = 3.7%, S/N = 3). The detection was feasible without any problem of matrix effect or cross reactivity in the linearity range of concentration varying from 0.50 to 125.00 ppm of barbituric acid. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.