Determination of Carmoisine onto Carbon-Paste Electrode Modified by Silica Impregnated with Cetylpyridinium Chloride

In this paper a simple, cheap and sensitive electrochemical sensor for determination of Carmoisine in soft drinks was developed. Carmoisine is a synthetic azo dye which is used in food products. In this work effective voltammetric sensor based on carbon-paste electrode modified by silica impregnated with cetylpyridinium chloride to increase the sensitivity of Carmoisine detection was proposed. The voltammetric behavior of Carmoisine, the number of protons and electrons involved in the oxidation process were studied. The probable mechanism of Carmoisine oxidation on the developed sensor was suggested. The optimal conditions for the square-wave voltammetric determination of Carmoisine onto developed sensor were found to be: pH=2; E-ads=400 mV; t(ads)=300s; A=50 mV; nu=25 Hz, upsilon=100 mV/s. The calibration curve was linear in the range of Carmoisine concentrations 0,08-1 mu M. The proposed method was successfully tested in the analysis of Carmoisine in soft drinks with RSD not more than 5%.