2-氨基-2-甲基丙醇化学改良气相色谱—质谱法分析马齿苋脂肪酸

Analysis of Fatty Acids from Purslane by Gas Chromatography-Mass Spectrometry with 2-amino-2-methylpropanol Chemical Modifying

以2-氨基-2-甲基丙醇为脂肪酸的化学改良试剂,建立了分析齿苋脂肪酸的化学改良气相色谱ET质谱法,通过将脂肪酸羧基修改为含氮杂环抑制了脂肪链中碳碳双键在ET源中的移位,并使质谱呈现显示双键位置的规范信息。解析脂肪酸2-氨基-2-甲基丙醇衍生物的EI质谱图,确定了马齿苋脂肪酸中碳碳双键位置。鉴定出马齿苋10种脂肪酸,由C16～C22脂肪酸组成,多不饱和脂肪酸总相对含量为70.64%,其中9,12,15-十八碳三烯酸(亚麻酸)相对含量达50.08%,还检出了在植物中极少为见的5,8,11,14,17-二十碳五烯酸(EPA)和4,7,10,13,16,19-二十二碳六烯酸(DHA)。

A gas Chromatography-electron impact mass spectrometric method was developed for analyzing the compositionof the fatty acids form purslane 2-amino-2-methylpropanol was used as chemical modifying reagent to the fatty acids. Modifyingcarboxyl group into nitrogen-contaning heterocycle effectively suppressed the migration of double bonds in the fatty acid chainunder the electron impact source and led to regular informative mass spectra regarding the position of the olefinic bonds in thechain. The position of double bonds of the fatty acids form purslane was located by analyzing electron impact mass spectra of2-amino-2-methylpropanol derivatives of the fatty acids. 10 fatty acids were identified according to the analysis of GC-EIMS.Purslane consisted of the fatty adids of C16～C22 and 70.64% of them were polyunsaturated fatty acids. The main componentof the polyunsaturated fatty acids was 9,12,15-linolenic acid whose relative content was 50.08. Besides, 5,8,11,14,17-eicosapentaenoic acid(EPA)and 4,710,13,16,19-docosahexenoic acid(DHA)which existed rarely in other plants were identified.