title: Spectroscopic characterisation of dimeric oxidation products of phytosterols.
abstract: Sterol dimers are the main oxidation products formed during sterols degradation at elevated temperatures. An investigation was carried out to decipher the structure of dimers differing in polarity, formed during β-sitosterol thermo-oxidation. The oxidation products were fractionated using silica gel into non-polar (NP), mid-polar (MP) and polar fractions (P). Oligomers were further separated by size-exclusion chromatography (SEC). Tentative chemical structures of non-polar, mid-polar and polar dimers were identified using Ag(+)/CIS-MS and APCI-MS procedures after on-line RP-HPLC separation. Further structures were verified by NMR and FT-IR spectroscopies.
authors.affiliation: Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland. Electronic address: esosinska@ibb.waw.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Sosińska
authors.affiliation: Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada.
authors.forename: Roman
authors.initials: R
authors.lastname: Przybylski
authors.affiliation: Max Rubner-Institut (MRI), Federal Research Institute for Nutrition and Food, D-32756 Detmold, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Aladedunye
authors.affiliation: Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Hazendonk
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010084:Oxidation-Reduction; D010840:Phytosterols / Q000737:chemistry*
chemical_list: D010840:Phytosterols
keywords: APCI–MS; BDE; CIS–MS; COSY; DEPT; Dimer; Disteryl ether; ELSD; FT-IR; Fourier transform infrared; HMBC; HSQC; NMR; NOESY; SEC; Thermo-oxidation; atmospheric pressure chemical ionisation–mass spectrometry; bond dissociation enthalpy; coordination-ion spray – mass spectrometry; distortionless enhancement by polarization transfer; evaporative light scattering detector; heteronuclear multiple bond correlation; heteronuclear single quantum coherence; nuclear Overhauser enhancement spectroscopy; size-exclusion chromatography; two-dimensional proton correlation spectroscopy; β-Sitosterol