title: Validation of a screening method for the simultaneous identification of fat-soluble and water-soluble vitamins (A, E, B1, B2 and B6) in an aqueous micellar medium of hexadecyltrimethylammonium chloride.
abstract: Simultaneous determination of the fat-soluble vitamins A and E and the water-soluble vitamins B1, B2 and B6 has been carried using a screening method from fluorescence contour graphs. These graphs show different colour zones in relation to the fluorescence intensity measured for the pair of excitation/emission wavelengths. The identification of the corresponding excitation/emission wavelength zones allows the detection of different vitamins in an aqueous medium regardless of the fat or water solubility of each vitamin, owing to the presence of a surfactant which forms micelles in water at the used concentration (over the critical micelle concentration). The micelles dissolve very water insoluble compounds, such as fat-soluble vitamins, inside the aggregates. This approach avoids the use of organic solvents in determining these vitamins and offers the possibility of analysing fat- and water-soluble vitamins simultaneously. The method has been validated in terms of detection limit, cut-off limit, sensitivity, number of false positives, number of false negatives and uncertainty range. The detection limit is about microg L(-1). The screening method was applied to different samples such as pharmaceuticals, juices and isotonic drinks.
authors.affiliation: Dpto. Química Analítica, Facultad de Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km. 33.6, 28871, Alcalá de Henares (Madrid), Spain.
authors.forename: V
authors.initials: V
authors.lastname: León-Ruiz
authors.forename: S
authors.initials: S
authors.lastname: Vera
authors.forename: M P
authors.initials: MP
authors.lastname: San Andrés
mesh_terms: D001628:Beverages; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D005223:Fats / Q000737:chemistry; D012256:Riboflavin / Q000032:analysis; D012995:Solubility; D013831:Thiamine / Q000032:analysis; D014801:Vitamin A / Q000032:analysis; D025101:Vitamin B 6 / Q000032:analysis; D014810:Vitamin E / Q000032:analysis; D014815:Vitamins / Q000032:analysis*; D014867:Water / Q000737:chemistry
chemical_list: D002593:Cetrimonium Compounds; D005223:Fats; D014815:Vitamins; D014867:Water; D014801:Vitamin A; D014810:Vitamin E; D025101:Vitamin B 6; D012256:Riboflavin; D013831:Thiamine; D000077286:Cetrimonium