IDENTIFICATION AND QUANTIFICATION OF LIPID SULFATE ESTERS BY ELECTROSPRAY-IONIZATION MS/MS TECHNIQUES - CHOLESTEROL SULFATE
IDENTIFICATION AND QUANTIFICATION OF LIPID SULFATE ESTERS BY ELECTROSPRAY-IONIZATION MS/MS TECHNIQUES - CHOLESTEROL SULFATE
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DOI：
10.1021/ac00118a022
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发表时间：
1995-11-15
影响因子：
7.4
通讯作者：
LEHMANN, WD
中科院分区：
文献类型：
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作者：
METZGER, K;REHBERGER, PA;LEHMANN, WD
结合碰撞活化的负离子电喷雾电离质谱用于在磷酸单酯和磷酸二酯存在下特异性检测硫酸酯。研究了碰撞碎片离子形成的能量依赖性。磺基单酯在m/z 80处产生特异性[SO 3]（-）片段，而磷酸单酯在m/z 79处产生特异性[PO 3]（-）片段，在m/z 63处产生特异性[PO 2]（-）片段。此外，磺基-和磷酸单酯在m/z 97处均产生同量异位碎片离子，组成分别为[HSO 4]（-）或[H2 PO 4]（-）。与磷酸单酯相比，磷酸二酯以低2-3个数量级的相对丰度产生该碎片离子。通过对相应[M-H]（-）物质的M + 2卫星离子进行产物离子分析，可明确区分磺基酯和磷酸酯：在S-34存在下，碎片离子分裂成双峰，而磷酸酯的碎片离子保持单一同位素信号，从小鼠皮肤角质形成细胞的总脂质提取物中鉴定和定量胆固醇3-硫酸盐，无需色谱分离，使用二氢胆固醇3-硫酸盐作为内标。在表皮分化过程中，胆固醇3-硫酸盐的水平从基底细胞中发现的约16 ng/10（6）个细胞增加到在最分化的细胞中观察到的约400 ng/10（6）个细胞。
Negative ion electrospray ionization mass spectrometry combined with collisional activation is used for specific detection of sulfate esters in the presence of phosphomonoesters and phosphodiesters. The energy dependence for the formation of the relevant collision-induced fragments ions is investigated. Sulfomonoesters give rise to a specific [SO3](-) fragment at m/z 80, whereas phosphomonoesters generate a specific [PO3](-) fragment at m/z 79 and a specific [PO2](-) fragment at m/z 63, In addition, both sulfo- and phosphomonoesters generate an isobaric fragment ion at m/z 97, with the composition [HSO4](-) or [H2PO4](-), respectively, Phosphodiesters generate this fragment ion with 2-3 orders of magnitude lower relative abundance compared to phosphomonoesters. A clear discrimination between sulfo- and phosphoesters was achieved by product ion analysis of the M + 2 satellite ion of their corresponding [M - H](-) species: in the presence of S-34, the fragment ions split into doublets, whereas the fragment ions of phosphate esters remain monoisotopic signals, Cholesterol 3-sulfate is identified and quantitated from total lipid extracts of mouse skin keratinocytes without chromatographic separation and using dihydrocholesterol 3-sulfate as internal standard. During epidermal differentiation, the level of cholesterol 3-sulfate increases from about 16 ng/10(6) cells found in basal cells to about 400 ng/10(6) cells observed in the most differentiated cells.