In situ analysis of soybean and nuts by Probe Electrospray Ionization mass spectrometry

PETROSELLI GABRIELA; MANDAL MRIDUL; CHEN LEE; HIRAOKA KENZO; NONAMI HIROSHI; ERRA BALSELLS ROSA

JOURNAL OF MASS SPECTROMETRY

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2015 vol. 50 p. 676 - 682

1076-5174

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. Itwas 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 increasedwith days of exposition.Monitoring sensitivity of PESI-MS was high. Thismethod 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.