TANDEM QUADRUPOLE MASS SPECTROMETRY OF SULFATIDES

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。硫酸酯通过电喷雾电离以负离子模式产生强烈的去质子化分子种类（[M-H]-）。用串联四极杆和离子阱质谱仪获得的硫酸酯的[M-H]-离子的产物离子谱包含丰富的碎片离子，可为长链碱和脂肪酸组分的结构测定提供信息，包括其不饱和键的位置。通过前体离子或恒定中性损失扫描，可以促进混合物中的硫苷脂或因长链碱基而变化的特定硫苷脂亚类的鉴定，或具有α-羟基脂肪酸取代基的硫苷脂类与具有非羟基脂肪酸基团的硫苷脂类的区分。虽然[M-H]-离子的CAD产物-离子光谱可用于区分异构体结构，但在低能CAD下的硫苷脂的碎裂过程的潜在机制可通过各种硫苷脂（包括其H-D交换类似物）的多级离子阱串联质谱法来揭示。另一方面，在正离子模式下通过ESI观察到的作为[M + Na]+离子的硫苷脂的灵敏度较差。硫苷脂[M + Na]+离子的产物离子谱包含很少的结构信息离子，对结构鉴定没有用。

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