Electrochemical sensor for hazardous food colourant quinoline yellow based on carbon nanotube-modified electrode

A novel electrochemical method using multi-wall carbon nanotube (MWNT) film-modified electrode was developed for the detection of quinoline yellow. In pH 8 phosphate buffer, an irreversible oxidation peak at 0.71 V was observed for quinoline yellow. Compared with the unmodified electrode, the MWNT film-modified electrode greatly increases the oxidation peak current of quinoline yellow, showing notable enhancement effect. The effects of pH value, amount of MWNT, accumulation potential and time were studied on the oxidation peak current of quinoline yellow. The linear range is from 0.75 to 20 mg L−1, and the limit of detection is 0.5 mg L−1. It was applied to the detection of quinoline yellow in commercial soft drinks, and the results consisted with the value that obtained by high-performance liquid chromatography.