Assessment of a portable device to quantify vitamin A in fortified foods (flour, sugar, and milk) for quality control

Background. Simple-to-use quantitative methods are needed to check the adequacy of vitamin A fortification levels. Objective. To assess the capacity of a portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) to quantify retinyl palmitate in fortified milks, flours (wheat, maize), and sugar. Methods. The portable fluorometer was assessed in a three-step procedure to determine its working range and linearity, intra-assay precision, and interperson precision. Measurements were compared with the results obtained by high-performance liquid chromatography (HPLC), commonly regarded as the standard method for vitamin A analysis. Results. The portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) precisely determined the vitamin A contents in fortified flours, sugar, and milks. Its working range was 1 to 10, 0.5 to 3.0, and 5 to 15 mg retinol equivalents (RE) kg –1 for flours (wheat and corn), milks, and sugar, respectively; these values are in accordance with the World Health Organization recommendations for food fortification in least developed countries. The limits of detection are higher than those of HPLC but are all satisfactory (< 1.46 mg RE kg –1 ). The coefficients of variation within and between observers were satisfactory, especially for sugar and milk. Conclusions. The linear relationship between the data from the portable fluorometer and the HPLC data confirms that the portable fluorometer provides a good determination of the vitamin A content of the fortified products in the tested range.