Reliable Determination of Sudan Dyes in Hot Sauce

Abstract

Sudan dyes are synthetic chemical and moderately polar dyes that have very similar chemical structure. Sudan dyes are of the azo group (-N=N-) and are oil soluble, aromatic compounds. Sudan I, II, III and IV are red dyes that are used for artificially colouring hydrocarbon solvents, waxes, oils, petrol, plastics, textile, shoe and floor polishes. The use of these dyes in food at any level is not allowed due to their health concerns and carcinogenic effect. Sudan dyes are not permitted in the regulations of many countries such as U.A.E, EU, Canada, Australia, China and Hong Kong. In spite of this fact, Sudan dyes have been found in several food products, for instance, Sudan I have been found in chilli products in the UK, July 2003 with great amounts in more than 400 products. Therefore, the determination and assessing of Sudan dyes has been turned on. A total of 38 hot sauce samples were purchased and collected randomly from different local markets and brands from both Cairo and Giza governments. For Sudan determination, a gel permeation chromatography (GPC) and high performance liquid chromatography (HPLC) were used. The method validation performance was tested on hot chilli samples and the GPC clean-up was found to be at 12 minutes in addition to the limit of quantification (LOQ) at expected lowest quantification level of 1 mg/kg for the 38 samples of hot sauce. Moreover, other method validations was done in this work, including method linearity, accuracy, trueness, precision, repeatability, reproducibility and uncertainty.