Determination of Sunset yellow in foods based on a facile electrochemical sensor

A new electrochemical sensor to determine Sunset yellow (SY) in foods has been developed. A composite consisting of highly dispersed polypyrrole (ppy) and single-walled carbon nanotube (ppy-SCNT) was synthesized as a modification via a facile method at room temperature. The ppy-SCNT composites were demonstrated to be highly sensitive for SY detection. The influences of pH value, amount of ppy-SCNT dispersion, accumulation time and scan rate on the signal enhancement of SY are discussed. Under optimal experimental conditions, the ppy-SCNT modified glass carbon electrode (ppy-SCNT/GCE) exhibited a wide linear response to SY ranging from 2.0 x 10(-9) to 1.5 x 10(-6) M with a high sensitivity of 91.53 mu A mu M-1 and a low detection limit of 3.0 x 10(-10) M (S/N = 3). The novel ppy can prevent the aggregation of SCNT via pi-pi interaction, and enhance their electrochemical properties for the measurement of Sunset yellow in food samples. The novel sensor possesses following features: facile fabrication, easy operation and acceptable stability. The analysis of real sample drinks demonstrated that the electrode has excellent selectivity.