Determination of Sudan I in food samples using a modified nanostructure paste electrode

Sudan dyes belong to a family of industrial dyes normally used for colouring plastics and other synthetic materials. Up to now four Sudan dyes have been detected in certain food products, inparticular Sudan I and Sudan IV (or Scarlet Red) [1]. Sudan I has also been adopted for colouring various foodstuffs, especially curry powder and chili powder, although the use ofSudan I in foods is now banned in many countries, because Sudan I, Sudan III, and Sudan IVhave been classified as category 3 carcinogens (not classifiable as to its carcinogenicity to humans) [2] by the International Agency for Research on Cancer.[2] Sudan I is still used in some orange-coloured smoke formulations and as a colouring for cotton refuse used in chemistryexperiments [2]. Therefore, determination of sudan I is very important in food samples. In this work, a simple and high sensitivity electrochemical sensor was developed to determine Sudan I based on NiO/NPs ionic liquid modified carbon paste electrode using cyclicvoltammetry, electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) methods. The novel sensor exhibited an obviously catalytic activity towards theoxidation of Sudan I, which can be confirmed by the increased oxidation peak current and the decreased oxidation peak potential when compared with the bare carbon paste electrode (CPE).The linear response range and detection limit were found to be 0.1–550 μM and 0.07 μM,respectively. Other species did not interfere with the determination of Sudan I at a surface of propose sensor in the optimum condition. The proposed sensor was successfully applied for the determination of Sudan I in food samples with satisfactory results.

Keywords:

Sudan I , Food analysis , Voltammetric sensor , Ionic liquid