基于电喷雾-四极杆-飞行时间质谱的神经节苷脂的结构解析

Structural Analysis of Gangliosides Based on Electrospray Quadrupole Time-of-Flight Mass Spectrometry

神经节苷脂(Ganglioside)是一种含有唾液酸的鞘糖脂化合物,是脊椎动物细胞膜的天然成份,具有广泛的生理功能。对神经节苷脂进行结构鉴定,有助于深入了解药物的组成,提高药物的品质,但由于神经节苷脂结构复杂,异构体众多,质谱规律变得多样且复杂。本研究建立了一种利用电喷雾-四极杆-飞行时间质谱的(ESI-Q-TOF-MS)解析神经节苷脂结构的方法。通过两个神经节苷脂对照品,优化质谱参数并总结质谱规律,建立质谱方法为:正离子模式; 3500 V毛细管电压; 200 V Fragmentor电压;用40 eV的碰撞能获得糖链的碎片结构,用80 eV的碰撞能获得神经酰胺的碎片结构。将本方法应用于制备的9个神经节苷脂的结构解析中,通过与对照品分子量对比,对样品进行简单的归属和分类,再根据样品的二级质谱中的特征碎片进行详细的结构解析。本研究结果表明,本方法可用于各类神经节苷脂的质谱鉴定中,为更复杂的神经节苷脂质谱解析奠定了基础。

Gangliosides are glycosphingolipid compounds containing sialic acid, which are natural components of vertebrate cell membranes. As a clinical drug, gangliosides are widely used in the treatment of hypoxic ischemic encephalopathy, central nervous system injury, neurodegenerative diseases and peripheral neuropathy. The structural identification of gangliosides helps to understand the composition of the drug and improve the quality of the drug. In this work, an electrospray ionization quadrupole time-of-flight mass spectrometry(ESI-Q-TOF-MS) method for analysis of ganglioside structure was established. The optimization of the mass spectrometry parameters were established based on testing of two gangliosides controls. The mass spectrometry conditions were established(positive mode, capillary voltage of 3500 V, fragmentor voltage of 200 V, and collision energy of 40 eV) to obtain the fragment structure of the sugar chain. The fragmentation structure of ceramide was obtained with collision energy of 80 eV. The method was applied to the structural analysis of 9 gangliosides prepared in the laboratory. The samples were categorized and classified by comparison with molecular weights of the reference substances. Detailed structure analysis was performed based on the characteristic fragments in the secondary mass spectra of the samples. The results of this study indicated that the method could be applied to the mass spectrometric identification of various gangliosides, laying a foundation for more complex ganglioside mass spectrometry analysis.