Electrochemical determination of Sudan I in food samples at graphene modified glassy carbon electrode based on the enhancement effect of sodium dodecyl sulphonate

This paper describes a novel electrochemical method for the determination of Sudan I in food samples based on the electrochemical catalytic activity of graphene modified glassy carbon electrode (GMGCE) and the enhancement effect of an anionic surfactant: sodium dodecyl sulphonate (SDS). Using pH 6.0 phosphate buffer solution (PBS) as supporting electrolyte and in the presence of 1.5 × 10−4 mol L−1 SDS, Sudan I yielded a well-defined and sensitive oxidation peak at a GMGCE. The oxidation peak current of Sudan I remarkably increased in the presence of SDS. The experimental parameters, such as supporting electrolyte, concentration of SDS, and accumulation time, were optimised for Sudan I determination. The oxidation peak current showed a linear relationship with the concentrations of Sudan I in the range of 7.50 × 10−8–7.50 × 10−6 mol L−1, with the detection limit of 4.0 × 10−8 mol L−1. This new voltammetric method was successfully used to determine Sudan I in food products such as ketchup and chili sauce with satisfactory results.