Studies on sulfatides by quadrupole ion-trap mass spectrometry with electrospray ionization: Structural characterization and the fragmentation processes that include an unusual internal galactose residue loss and the classical charge-remote fragmentation
Studies on sulfatides by quadrupole ion-trap mass spectrometry with electrospray ionization: Structural characterization and the fragmentation processes that include an unusual internal galactose residue loss and the classical charge-remote fragmentation
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DOI：
10.1016/j.jasms.2003.12.007
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发表时间：
2004-04-01
影响因子：
3.2
通讯作者：
Turk, J
中科院分区：
文献类型：
--
作者：
Hsu, FF;Turk, J
采用碰撞活化解离（CAD）四极杆离子阱串联质谱电喷雾电离方法对硫苷脂的结构进行了表征。当在负离子模式下进行CAD时，硫酸酯的[M-H]（-）离子会产生丰富的结构信息离子，可以明确地分配长链碱基和脂肪酸成分，包括双键的位置。的脂肪酰基取代基上的双键的位置的识别是基于观察的一系列的离子所产生的经典的电荷远程碎裂过程类似于通过高能CAD和串联四极质谱所观察到的那些。一个不寻常的内部半乳糖残基的损失，由于重排过程中也观察到。硫苷脂的[M-H]（-）离子也解离成神经酰胺阴离子，其经历连续的碎裂过程以产生用于识别神经酰胺部分的信息离子，并允许区分具有鞘氨醇亚类的硫苷脂与具有二氢鞘氨醇长链碱基亚类的硫苷脂。具有鞘氨醇LCB和α-羟基脂肪酰基取代基的硫苷脂亚类（d18：1/hFA-硫苷脂）的MS 2-光谱特征为m/z 568、550、540和522的突出离子集，源自脂肪酰基CO-CH（OH）键的初级裂解，并且很容易与非羟基硫苷脂亚类（d18：1/nFA-硫苷脂）的离子集区分开来，其中离子集丰度较低。提出了低能CAD条件下硫苷类化合物的裂解途径。各种化合物及其H-D交换类似物的MS 2-和MS 3-光谱支持这些途径。(C)2004年美国质谱学会。
The structural characterization of sulfatides by collisional-activated dissociation (CAD) quadrupole ion-trap tandem mass spectrometric methods with electrospray ionization is described. When subjected to CAD in the negative-ion mode, the [M - H](-) ions of sulfatides yield abundant structurally informative ions that permit unequivocal assignments of the long-chain base, and fatty acid constituent including the location of double bond. The identification of the position of the double bond on the fatty acyl substituent is based on the observation of the series of the ions arising from classical charge-remote fragmentation processes similar to those observed by high-energy CAD and by tandem quadrupole mass spectrometry. An unusual internal galactose residue loss due to a rearrangement process was also observed. The [M - H](-) ions of sulfatides also dissociates to a ceramide anion, which undergoes consecutive fragmentation processes to yield ions informative for identification of the ceramide moiety and permits distinction the sulfatide with a sphingosine subclass from that with a sphinganine long-chain base subclass. The MS2-spectra of the sulfatide subclass with a sphingosine LCB and a alpha-hydroxy fatty acyl substituent (d18:1/hFA-sulfatide) are featured by the prominent ion sets of m/z 568, 550, 540, and 522, originated from a primary cleavage of the fatty acyl CO-CH(OH) bond, and are readily differentiable from those arising from the non-hydroxy sulfatide subclass (d18:1/nFA-sulfatide), in which the ion sets are of low abundance. The fragmentation pathways of sulfatides under low-energy CAD are proposed. The pathways are supported by the MS2- and MS3-spectra of various compounds, and of their H-D exchanged analogs. (C) 2004 American Society for Mass Spectrometry.