Gas phase derivatization for lipidomic MS analysis

描述（由申请人提供）：目前获得认可的脂质组学方法是基于对脂肪酰基中的碳长度和不饱和度及其在甘油酯sn 1、2或3位置的位置（区域特异性）进行快速、全面的质谱（MS）分析。脂质组学分析面临的最重要的分析问题是，没有出现同时提供脂肪酰基中的双键位置和区域特异性信息的通用方法。我们提出利用我们实验室开发的新型质谱方法，该方法应该能够完整地自动表征粗脂质提取物中的所有酰化脂质，在化学电离（Cl）质谱（MS）过程中产生加合物的离子-分子反应实际上是一种气相衍生过程。自1999年以来，我们在一系列的8篇论文中报道了不饱和脂肪酸甲酯（FAME）的乙腈CI/MS/MS气体衍生化的共同发现。所得加合物的裂解提供了第一个快速，方便的结构分析FAME。乙腈Cl在m/z 54处产生离子，其在双键上共价加成;所得[M+54]+离子在碰撞活化后经历电荷驱动的碎片化，以产生明确确定多不饱和化合物中双键位置的诊断离子。最近，在大气压C1下在液体流中观察到了该反应。我们提出了一种双管齐下的方法，其中我们1）开发基于乙腈的APCI，用于分析来自粗脂质提取物的脂质类中脂肪酰基的双键位置，2）完成乙腈GClCIIMS的开发，以包括所有多不饱和非亚甲基中断脂肪酸的分析。这些目标最终将被耦合，并与传统的MS/MS模式（前体，产品，和中性损失扫描），气相衍生的含酰基化合物的分析应提供完整的结构和定量信息的大多数甘油脂，可以自动化的lipidomic分析。

DESCRIPTION (provided by applicant): Lipidomic approaches now gaining acceptance are based on the rapid, comprehensive mass spectrometry (MS) analysis of carbon length and degree of unsaturation in fatty acyl groups and their positions (regiospecificity) at the sn 1,2, or 3 positions of glycerolipids. The most important analytical issue facing lipidomic analysis is that no general method has emerged that delivers double bond position in the fatty acyl groups simultaneously with regiospecific information, We propose to exploit a novel mass spectrometric method developed in our laboratory that should enable complete, automated characterization of all acylated lipids in crude lipid extracts, Ion-molecule reactions that result in adducts during chemical ionization (Cl) mass spectrometry (MS) are effectively a gas phase derivatization process. In a series of 8 papers since 1999, we reported co-discovery of gas derivatization of unsaturated fatty acid methyl esters (FAME) by acetonitrile CI/MS/MS. Fragmentation of the resulting adducts provides the first rapid, convenient structural analysis of FAME. Acetonitrile CI produces an ion at m/z 54 which adds covalently across double bonds; the resulting [M+54]+ ion undergoes charge-driven fragmentation upon collisional activation to yield diagnostic ions that unequivocally establish the position of double bonds in polyunsaturates. Recently, this reaction has been observed for atmospheric pressure CI in a liquid stream. We propose a two pronged approach where we 1) develop APCI based on acetonitrile for analysis of double bond position for fatty acyl groups within lipid classes derived from crude lipid extracts, and 2) complete development of acetonitrile GClCIIMSlMS to include analysis of all polyunsaturated non-methylene-interrupted fatty acids. These goals will eventually be coupled, and together with conventional MS/MS modes (precursor, product, and neutral loss scans), analysis of gas phase derivatized acyl-containing compounds should provide complete structural and quantitative information for most glycerolipids and can be automated for lipidomic analysis.