北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University;第57巻 第3号

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ホシゴマシズ筋肉脂質由来1-O-アルキルグリセロールのキラル高速液体クロマトグラフィー/大気圧化学イオン化質量分析

山科, 智裕;李, 鍾壽;板橋, 豊

Permalink : http://hdl.handle.net/2115/32488
KEYWORDS : Alkylglycerol;Alkyldiacylglycerol;Atmospheric pressure chemical ionization mass spectrometry;Chiral-phase HPLC;3,5-Dinitrophenylurethane;Enantiomer;Molecular species;Post-column solvent addition;Stromateus Stellatus

Abstract

The chirality and molecular species of 1-O-alkylglycerols derived from muscle lipids from a Stromateidei fish, Stromateus Stellatus, were determined by chiral-phase high-performance liquid chromatography (HPLC) and mass spectrometry (MS). For this purpose, 1-O-alkylglycerols were derived from 1-O-alkyl-2, 3-diacylglycerols by methanolysis and were then converted into bis-3,5-dinitrophenylurethane (DNPU) derivatives. These were then analyzed by chiral-phase HPLC in conjunction with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The HPLC separation was performed on a column (25cm×4.6mm i.d., 5μm particle size) having a chiral phase of N-[(S)-1-(1-naphthyl) ethylaminocarbonyl]-(S)-tert-leucine and using hexane/dichloromethane/ethanol (40:12:4, by vol) as the mobile phase. The APCI-MS was carried out using an iontrap mass spectrometer. Post-column addition of 2-propanol was used to assure APCI in the negative mode. In addition to a prominent solvent adduct ion [DNPU+CH3CH(OH)CH3-H]- (base peak), the spectra showed [M-DNPU]-, [M-DNPU+Cl]- and [M+Cl]-ions, from which the major molecular species could be identified. The results clearly showed that the glycerol moieties in all the alkylglycerols had an S-configuration (sn-1-O-) and that the major molecular species were 14:0,16:0,and 18:1. The fragment ions related to the minor components (18:0,16:1,17:0 and 20:1), which were previously detected by chiral-phase HPLC/electrospray ionization MS [Yamashina, Lee and Itabashi : Bunseki Kagaku, 55, 643-650 (2006)], were not observed under the conditions employed. Thus, the present method demonstrates that the chiral-phase HPLC/APCI-MS provides unambiguous information about the chirality and can be used for identification of the major molecular species of natural 1-O-alkylglycerols.

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