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目的:利用能量分辨曲线建立有效区分氧化脂类的质谱方法,为氧化脂类在细胞信号传导过程中机理的研究提供高灵敏、高效的异构体区分手段,特别是在没有对照品的情况下可以迅速地区分出氧化脂类位置异构体。方法:对照品经甲醇溶解,0.22μm滤膜过滤后上机分析。采用电喷雾电离源负离子电离模式,喷雾电压2.6 kV,鞘气(N2)流量400 L·h-1,辅助气(N2)流量1 Arbs,离子传输毛细管温度250℃,扫描采用二级质谱子离子扫描模式,碰撞能量5~25 eV。结果:4对氧化脂类异构体PGB2和PGA2,PGE1和PGD1,5(R)-HETE、12(S)-HETE和15(S)-HETE,9(S)-HODE和13(S)-HODE不同碰撞能量下母离子与碎片离子绘制出能量分辨曲线。其中3对异构体PGE1和PGD1,9(S)-HODE和13(S)-HODE,5(R)-HETE、12(S)-HETE和15(S)-HETE)结构上的主要区别在于羟基位点不同,结果表明羟基位点离末端羧基位点较远,则在能量分辨曲线中表现为离子能量曲线变化趋势较小,化合物较稳定;而异构体(PGA2和PGB2)在结构上的主要区别是双键位置不同,在能量分辨曲线上可以观察到共轭体系的存在使得化合物相对稳定。并通过海带中存在的4种氧化脂类进行了验证,经稳定性试验分析,这4对氧化脂类日内、日间RSD小于7%。结论:本研究有效区分了前列腺素B2(PGB2)、前列腺素A2(PGA2)、前列腺素E1(PGE1)、前列腺素D1(PGD1)等9个氧化脂类成分,质谱能量分辨曲线法适用于氧化脂类位置异构体快速区分。
OBJECTIVE: To establish an effective mass spectrometric method to distinguish oxidized lipids from energy-resolved curves, and to provide a highly sensitive and efficient means of distinguishing isoforms for the study of the mechanism of oxidative lipids in cell signaling, especially in the absence of reference substance Oxidative lipid positional isomers can be rapidly distinguished. Methods: The reference substance was dissolved in methanol and filtered on a 0.22 μm membrane filter. The electrospray ionization source ionization mode was used. The spray voltage was 2.6 kV, the flow rate of sheath gas (N2) was 400 L · h-1, the flow rate of auxiliary gas was 1 Arbs, the temperature of ion-transport capillary was 250 ℃. Scan mode, collision energy 5 ~ 25 eV. Results: Four pairs of oxidized lipid isomers PGB2 and PGA2, PGE1 and PGD1,5 (R) -HETE, 12 (S) -HETE and 15 (S) -HETE, -HODE The energetic resolution curves of precursor ions and fragment ions are plotted under different collision energies. The main structural differences between the 3 pairs of isomers PGE1 and PGD1,9 (S) -HODE and 13 (S) -HODE, 5 (R) -HETE, 12 (S) -HETE and 15 (S) -HETE The result showed that the hydroxyl sites were far away from the terminal carboxyl sites, and the trend of ion energy curve was smaller and the compounds were more stable in the energy-resolved curve. The isomers (PGA2 and PGB2) The main difference is that the position of the double bonds is different. It is observed on the energy resolution curve that the presence of the conjugated system makes the compound relatively stable. The results showed that the four pairs of oxidized lipids had a daily RSD of less than 7% during the day. Conclusion: This study effectively distinguishes nine oxidized lipid components such as prostaglandin B2 (PGB2), prostaglandin A2 (PGE2), prostaglandin E1 (PGE1) and prostaglandin D1 (PGD1). The energy- Lipid positional isomers are quickly distinguished.