title: An approach based on ultrahigh performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry allowing the quantification of both individual phytosteryl and phytostanyl fatty acid esters in complex mixtures.
abstract: A method for the analysis of both individual phytosteryl and phytostanyl fatty acid esters in complex mixtures was established. The approach was based on a previously not described combination of three elements: (i) the formation of [M-FA+H](+) fragment ions via APCI (atmospheric pressure chemical ionization), (ii) a highly efficient UHPLC-based separation on a 1.7 μ C8 column, previously established for phytostanyl fatty acid esters, allowing the distinction of individual fatty acid esters sharing the same sterol/stanol nucleus and of isotope peaks of phytosteryl fatty acid esters and corresponding phytostanyl fatty acid esters based on these [M-FA+H](+) fragment ions, and (iii) the adjustment of the APCI conditions allowing the differential APCI-MS-SIM (single ion monitoring) detection of phytostanyl esters of linoleic and linolenic acid based on their distinct formation of a [M+H](+) ion. The usefulness of the methodology was demonstrated by the analysis of a commercially available enriched margarine. Two runs per sample allowed the quantification of 35 target analytes; the total amounts of esters were between 124.7 and 125.3g/kg, being in good agreement with the labelled 125 g/kg. Validation data were elaborated for 35 individual fatty acid esters of sitosterol, campesterol, brassicasterol, stigmasterol, sitostanol and campestanol. Recovery rates ranged from 95 to 106%; the coefficients of variation were consistently <5%, except for stigmasteryl-18:1. The approach describes for the first time a quantification of both individual phytosteryl and phytostanyl fatty acid esters and thus closes an analytical gap related to this class of health-relevant food constituents.
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Maximus-von-Imhof-Forum 2, D-85350 Freising, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Scholz
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Maximus-von-Imhof-Forum 2, D-85350 Freising, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Menzel
authors.affiliation: Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Veterinärstrasse 2, D-85764 Oberschleissheim, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Lander
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Maximus-von-Imhof-Forum 2, D-85350 Freising, Germany. Electronic address: k.h.engel@wzw.tum.de.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Engel
mesh_terms: D001274:Atmospheric Pressure; D002851:Chromatography, High Pressure Liquid; D045424:Complex Mixtures; D004952:Esters / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D008383:Margarine / Q000032:analysis; D013058:Mass Spectrometry; D015203:Reproducibility of Results
chemical_list: D045424:Complex Mixtures; D004952:Esters; D005227:Fatty Acids; D008383:Margarine
keywords: Enriched foods; Phytostanyl fatty acid esters; Phytosteryl fatty acid esters; RP-UHPLC–APCI–MS