Extraction-photometric determination of synthetic food dyes in liquid food products

Technical Regulations of the Customs Union 029/2012, «Safety requirements of food additives, flavorings and processing aids», apply on the territory of the Eurasian Economic Union member states. According to it, the 13 synthetic dyes ( SD ) can be used in food products at the level of 50-500 mg/kg. The extraction of food synthetic acid dyes (E 102, E 104, E 110, E 122, E 123, E 124, E 127, E 128, E 129, E 131, E 132, E 133, E 142, E 143, E 151, E 155) from the aqueous solutions with organic solvents and solutions of trioctyl methylammonium chloride (TOMAC) was studied. The determination of the dyes content in the phases was performed by photometry, the estimated parameters were the distribution coefficient ( D ) and the degree of extraction ( R , %). The principle possibility of selective extraction by organic solvents (chloroform, isoamyl alcohol) of the E 127 dye ( D > 24, R > 96 %), prohibited for use by the Technical Regulations of the Customs Union 029/2012, was shown. To a lesser extent, E 104 ( D = 1, R = 50 %) was extracted with isoamyl alcohol. Chloroform and toluene solutions of TOMAC with the concentration of 1·10 -2 M quantitatively extract the studied SD from the aqueous solutions with the concentration of 2·10 -4 M, but chloroform was the most effective. Based on the obtained data, the method for the quantitative determination of SD in liquid food products (juices, beverages, wines, etc.) was proposed. It consisted of the preliminary E 127 removal with chloroform and colored hydrophobic impurities, subsequent E 104 removal with isoamyl alcohol followed by the extraction of the remaining SD using the chloroform solution of TOMAC, and photometry of the extract. The conducted studies were confirmed by HPLC – DAD method. Key words: synthetic dyes, extraction, liquid ion exchanger, food products, trioctyl methylammonium chloride, distribution coefficient, HPLC DOI: http://dx.doi.org/10.15826/analitika.2020.24.3.004 Y. М . Pliashak 1 , S.M. Leschev 2 , A.I. Palianskikh 1 , L.L. Belysheva 1 , M.F. Zayats 2 1 Scientific Practical Center of Hygiene, ul. Akademicheskaya, 8, Minsk, 220012, Republic of Belarus 2 Belarusian State University, ul. Leningradskaya, 14, Minsk, 220050, Republic of Belarus