Determination of seven illegal dyes in Egyptian spices by HPLC with gel permeation chromatography clean up

Abstract

Sudan I, II, III, IV, Para Red, Orange G and Red 7B are synthetic regularly dyes utilized to dye plastics and other manufactured materials. In recent years, concerns about the genotoxic possibilities of Sudan colors have been raised. A few national bodies and food experts consider Sudan dyes to be genotoxic cancer-causing agents while others view these dyes as possible cancer-causing agents. Therefore, it is of the outmost importance to assess the risk and presence of Sudan dyes in Egyptian spices, including; sumac, hot chilli, cumin, paprika, curry and turmeric. A total of 83 samples were collected randomly from different supermarkets and spice shop in various municipalities of Egypt (Cairo, Giza, Qalyubia, Faiyum and Alexandria). For Sudan dyes determination, gel permeation chromatography (GPC) and high-performance liquid chromatography (HPLC) were used. Dyes were extracted from spices with acetonitrile and selectively initial separated by GPC. Fractions were collected from 12 min to 24 min and then determined by HPLC with diode array detection (HPLC-DAD). The method performance was validated on hot chilli samples, and the limit of quantification (LOQ) was 0.1 mg/kg for the seven Sudan dyes. Moreover, other method validation parameters were determined in this work, including linearity, accuracy, recovery, limit of detection (LOD), repeatability, reproducibility and expanded uncertainty. Finally, a market survey was conducted to assess the incidence of such illegal dyes and enlighten buyers, almost 50% of the tested samples were contaminated with Sudan dyes. Sudan Red 7B and Para Red were not detected in the samples, and the mean contamination level varied from 0.01 mg/kg for Sudan Ⅱ to 50.1 mg/kg for Sudan Ӏ. It is recommended to buy raw whole spices – not in powder form- and blend them at home. In addition, spices should be purchased from established retailers, and buyers should avoid spices with abnormally red shading.