title: Validation of a fast and accurate chromatographic method for detailed quantification of vitamin E in green leafy vegetables.
abstract: Vitamin E analysis in green vegetables is performed by an array of different methods, making it difficult to compare published data or choosing the adequate one for a particular sample. Aiming to achieve a consistent method with wide applicability, the current study reports the development and validation of a fast micro-method for quantification of vitamin E in green leafy vegetables. The methodology uses solid-liquid extraction based on the Folch method, with tocol as internal standard, and normal-phase HPLC with fluorescence detection. A large linear working range was confirmed, being highly reproducible, with inter-day precisions below 5% (RSD). Method sensitivity was established (below 0.02 μg/g fresh weight), and accuracy was assessed by recovery tests (>96%). The method was tested in different green leafy vegetables, evidencing diverse tocochromanol profiles, with variable ratios and amounts of α- and γ-tocopherol, and other minor compounds. The methodology is adequate for routine analyses, with a reduced chromatographic run (<7 min) and organic solvent consumption, and requires only standard chromatographic equipment available in most laboratories.
authors.affiliation: REQUIMTE, Laboratório de Bromatologia e Hidrologia, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors.forename: Rebeca
authors.initials: R
authors.lastname: Cruz
authors.forename: Susana
authors.initials: S
authors.lastname: Casal
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis*; D012680:Sensitivity and Specificity; D014675:Vegetables / Q000737:chemistry*; D014810:Vitamin E / Q000032:analysis*
chemical_list: D010936:Plant Extracts; D014810:Vitamin E