title: Determination of fat-soluble vitamins in yogurt by HPLC with electrochemical detection.
abstract: A method employing HPLC with electrochemical detection for the rapid and simultaneous determination of vitamins A, D(3) and E is described. The method uses a C-18 reverse phase column and 2.5 mM HAcO-NaAcO in methanol-water (99:1, v/v) solution as the mobile phase. The compounds are quantified using amperometric detection with a glassy carbon electrode at a potential of + 1300 mV (vs. Ag/AgCl) and the results are compared with those obtained using UV detection at a wavelength of 280 nm. The method was successfully applied to the analysis of vitamins A, D(3) and E in yogurt samples. After saponification, fat-soluble vitamins were extracted and the methanolic solution of the extracts was injected directly into the chromatographic system, avoiding the clean-up step which is necessary when no electrochemical detection is used. Good recovery percentages were obtained.
authors.forename: M M
authors.initials: MM
authors.lastname: Delgado Zamarreño
authors.forename: A
authors.initials: A
authors.lastname: Sanchez Perez
authors.forename: M
authors.initials: M
authors.lastname: Sanchez Rodriguez
authors.forename: M C
authors.initials: MC
authors.lastname: Gomez Perez
authors.forename: J
authors.initials: J
authors.lastname: Hernandez Mendez