TANDEM QUADRUPOLE MASS SPECTROMETRY OF SULFATIDES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。电喷雾电离法在负离子模式下产生强烈的去质子化分子（[M - H]-）。用串联四极杆和离子阱质谱仪获得的硫脂脂[M - H]-离子的产物离子谱含有丰富的片段离子，为确定长链碱基和脂肪酸成分及其不饱和键的位置提供了信息。通过前体离子或恒定中性损失扫描，可以方便地识别混合物中的硫fatide，或根据长链碱基变化的特定硫fatide亚类，或区分具有a-羟基脂肪酸取代基的硫fatide类和具有非羟基脂肪酸基的硫fatide类。虽然[M - H]-离子的CAD生成离子谱对异构体结构的区分是有用的，但在低能CAD下，硫脂质碎裂过程的机制可以通过对各种硫脂质（包括它们的H- d交换类似物）进行多级离子阱串联质谱分析来揭示。而在正离子模式下，用ESI观察到的[M + Na]+离子对硫脂的敏感性较差。硫脂的[M + Na]+离子的产离子谱中含有很少的结构信息离子，对结构鉴定没有帮助

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Sulfatides yield intense deprotonated molecular species ([M - H]-) in negative-ion mode by electrospray ionization. The product-ion spectra of the [M - H]- ions of sulfatides obtained with a tandem quadrupole and with an ion-trap mass spectrometers contain abundant fragment ions informative for structural determination of the long-chain base and the fatty acid constituent including the location of its unsaturated bond. Identifications of sulfatides in mixtures, or specific sulfatide subclasses that are varied by long-chain base, or differentiation of sulfatide class with a-hydroxy fatty acid substituent from that with non-hydroxy fatty acid group can be facilitated by precursor ion or constant neutral loss scans. While CAD product-ion spectra of the [M - H]- ions are useful for differentiation of isomeric structures, the mechanisms underlying the fragmentation processes for sulfatides under low-energy CAD can be unveiled by multiple-stage ion-trap tandem mass spectrometry of various sulfatides, including their H-D exchanged analogs. The sensitivity of sulfatides observed as the [M + Na]+ ions by ESI in the positive-ion mode, on the other hand, is poor. The product-ion spectra of the [M + Na]+ ions of sulfatides contain very few structurally informative ions and are not useful for structural identificati