title: Improved method for fatty acid analysis in herbage based on direct transesterification followed by solid-phase extraction.
abstract: Direct transesterification (DT) and solvent extraction with acid or basic derivatization procedure for fatty acid (FA) analysis in herbage were compared. The highest total FA, alpha-linolenic and linoleic acid contents were obtained with DT. However, DT also produced the highest amount of interfering compounds, identified as phytadienes and sugar derivative products, which may co-elute with FA. An additional step based on solid-phase extraction to produce clean samples was proposed. This procedure is simple and gives good recoveries for the FA fortified samples. Additionally, structural characterization of 16:1 trans-3 was conducted by covalent adduct chemical ionization tandem mass spectrometry.
authors.affiliation: REQUIMTE, Unidade de Produção Animal, Instituto Nacional de Recursos Biológicos, Fonte-Boa, 2005-048 Vale de Santarém, Portugal.
authors.forename: Susana P
authors.initials: SP
authors.lastname: Alves
authors.forename: Ana R J
authors.initials: AR
authors.lastname: Cabrita
authors.forename: António J M
authors.initials: AJ
authors.lastname: Fonseca
authors.forename: Rui J B
authors.initials: RJ
authors.lastname: Bessa
mesh_terms: D002849:Chromatography, Gas / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D004951:Esterification; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D005227:Fatty Acids; D010936:Plant Extracts