The Application Of Ionic Liquids-Graphene Composites In Sudan?Electrochemical Sensor

The illegal addition of Sudan?in food has become an important subject in food safety analysis, as it has been classified as an azo dye which is traditionally used in industrial products. Among the current detection methods, electrochemical techniques have attracted many attentions of the researchers due to their high sensitivity, low cost and simplicity. In this study, a Sudan?sensor was first fabricated based on poly(ionic liquids)(PILs) functionalized graphene by noncovalent functionalized approach. Second, the electrochemical reaction mechanism of Sudan?was discussed fully on the modified electrode of IL functionalized graphene. The main contents were summarized as follows:1. A Sudan?sensor was fabricated based on poly(ionic liquids)(PILs)functionalized graphene by noncovalent functionalized approach. Compared with a glassy carbon electrode(GCE), the modified electrode significantly enhanced the oxidation peak current of Sudan?. This increase in electrochemical response was attributed to the positive charge of poly(ionic liquids) which facilitates the accumulation of Sudan?and the network structure of the poly(ionic liquid)–graphene nanocomposite prepared by electrochemical reduction. Under optimized experimental conditions, the oxidation peak currents of Sudan?were linear to their concentrations in the range of 6.86×10-8 to 8.79×10-6 mol/L and the limit of detection of 2.3×10-8mol/L was obtained. Finally, the proposed sensing method was successfully employed to detect Sudan?in food products such as chili powder and ketchup with satisfactory results.2. Ionic liquid-reduced graphene oxide(IL-rGO) nanocomposite was fabricated by reflux-heating method without any hazardous or polluted reductants. Supported by cyclic voltammetry and chronocoulometry experiments, the electrochemical behavior of Sudan?was studied with some dynamic parameters calculated and the possible electrochemical reaction mechanism of Sudan?was proposed, which can be explained as ECE process. This mechanism is not identical.with the previous research. Finally, the Sudan?sensor could obtain the linear range of 6.79×10-7- 6.8×10-5mol/L with the limit of detection of 2.16×10-7mol/L.