PHOTOMETRIC DETERMINATION OF ERYTHROSIN IN THE PRESENCE OF SYNTHETIC ACIDIC DYES IN FOOD PRODUCTS

In Republic of Belarus and the countries of the EACU, the synthetic dye E 127 (erythrosine) is prohibited for the use in the production of food products. To control the content of this additive, accurate and rapid methods of determination are required. In order to develop a methodology for determination of erythrosin in the presence of food synthetic dyes (E 102, E 104, E 110, E 122, E 123, E 124, E 128, E 129, E 131, E 132, E 133, E 142, E 143 , E 151, E 155) the extraction of dyes with organic solvents from aqueous solutions was studied and their distribution coefficients were determined. Based on the data obtained in the presence of the above dyes, a method for determining E 127 without the use of expensive chromatographic equipment was proposed. The technique is based on sample preparation, which consists of the selective extraction of E 127 from an aqueous solution of the food matrix (pH=2) using chloroform. Other synthetic dyes were not extracted. Next, the extract was evaporated, dissolved in a buffer solution at pH=9 and photometrically measured at the wavelength of 527 nm. In the presence of hydrophobic organic dyes (carotene, lycopene) in the food matrix, their preliminary extraction was carried out from the aqueous solution at pH=9 with chloroform; under these conditions all dyes, including E 127, were not extracted. The limit of quantitative determination by the proposed method for liquid food products was 0.05 mg/kg, for solid – 0.13 mg/kg, the standard deviation was 2–3 %.