title: In situ analysis of soybeans and nuts by probe electrospray ionization mass spectrometry.
abstract: The probe electrospray ionization (PESI) is an ESI-based ionization technique that generates electrospray from the tip of a solid metal needle. In the present work, we describe the PESI mass spectra obtained by in situ measurement of soybeans and several nuts (peanuts, walnuts, cashew nuts, macadamia nuts and almonds) using different solid needles as sampling probes. It was found that PESI-MS is a valuable approach for in situ lipid analysis of these seeds. The phospholipid and triacylglycerol PESI spectra of different nuts and soybean were compared by principal component analysis (PCA). PCA shows significant differences among the data of each family of seeds. Methanolic extracts of nuts and soybean were exposed to air and sunlight for several days. PESI mass spectra were recorded before and after the treatment. Along the aging of the oil (rancidification), the formation of oxidated species with variable number of hydroperoxide groups could be observed in the PESI spectra. The relative intensity of oxidated triacylglycerols signals increased with days of exposition. Monitoring sensitivity of PESI-MS was high. This method provides a fast, simple and sensitive technique for the analysis (detection and characterization) of lipids in seed tissue and degree of oxidation of the oil samples.
authors.affiliation: CIHIDECAR-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II 3 P, Ciudad Universitaria, Buenos Aires, 1428, Argentina.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Petroselli
authors.affiliation: Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
authors.forename: Mridul K
authors.initials: MK
authors.lastname: Mandal
authors.affiliation: Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
authors.forename: Lee C
authors.initials: LC
authors.lastname: Chen
authors.affiliation: Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi, 400-8511, Japan.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hiraoka
authors.affiliation: Plant Biophysics/Biochemistry Research Laboratory, Faculty of Agriculture, Ehime University, Matsuyama, 790-8566, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nonami
authors.affiliation: CIHIDECAR-CONICET, Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II 3 P, Ciudad Universitaria, Buenos Aires, 1428, Argentina.
authors.forename: Rosa
authors.initials: R
authors.lastname: Erra-Balsells
mesh_terms: D010367:Arachis / Q000737:chemistry; D031324:Juglans / Q000737:chemistry*; D039106:Macadamia / Q000737:chemistry; D009754:Nuts / Q000737:chemistry*; D010743:Phospholipids / Q000032:analysis / Q000737:chemistry; D025341:Principal Component Analysis; D013025:Glycine max / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D014280:Triglycerides / Q000032:analysis / Q000737:chemistry
chemical_list: D010743:Phospholipids; D014280:Triglycerides
keywords: ESI-MS; PESI; almonds; cashew nuts; macadamia nuts; peanuts; pistachios; rancidification; walnuts