硼酸緩衝溶液毛細電泳質譜分析神經節苷酯靈敏度提升之研究

Sensitivity Improvement of Gangliosides Analysis by Capillary Electrophoresis / Electrospray Ionization Mass Spectrometry Using Nonvolatile Borate Buffer

薛運鴻(Yun-Hung Hsueh)

指導教授 ： 何國榮

國立臺灣大學/理學院/化學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02390

摘要

在毛細電泳分離神經節苷脂時，環糊精添加劑和硼酸緩衝溶液對於神經節苷酯分離具有重要的地位。然而，環糊精添加劑和硼酸系統緩衝溶液對負離子電噴灑有嚴重訊號抑制和電噴灑時會因結晶而造成噴頭的堵塞及噴灑不穩定。本研究利用有機添加劑取代環糊精並搭配低鞘流-液體接合式界面能有效地提升神經節苷醣在非揮發性硼酸緩衝溶液的靈敏度。有機添加劑能夠取代環糊精而有效的打破神經節苷脂的微胞，有機修飾劑的使用解決環糊精的抑制外還可以提升毛細電泳銜接負離子質譜儀的相容性。實驗數據顯示，使用低鞘流-液體接合式介面搭配毛細管塗佈能阻止硼酸根離子進入質譜端有效地降低硼酸緩衝溶液帶來的訊號抑制。雖然利用有機相取代環糊精可避免訊號抑制但在分離上卻犧牲抱合脂上不同碳數的解析度。

關鍵字

神經節苷脂 ； 毛細電泳質譜 ； 硼酸 ； 毛細管塗佈技術

並列摘要

Gangliosides are carbohydrate-rich sphingolipids with one or more sialic acid on the sugar moiety. These gangliosides have been shown to play important roles in biological processes such as cell growth and antiviral activity for human immunodeficiency virus (HIV). Because of its higher separation efficiency, capillary electrophoresis can effectively separate complex mixture. The most effective running buffer for the separation of gangliosides is borate buffer containing α-Cyclodextrin (α-CD) additive. The α-Cyclodextrins were critical for the breaking up of the micelles formed by amphiphilic ganglioside. Borate is a popular buffer in the analysis of glycans especially for isomer separation due to the interaction between boronic acid and diols of the glycans. Therefore, system using borate and α-CD buffer is indispensable for the separation of gangliosides by CE. Unfortunately, borate and α-CD were found to be not compatible with CE-ESI-MS. These non-volatile additives may crystallize to block the spray tip and also to suppress the analyte signals during ionization process. Two approaches were adopted to overcome these problems. Organic solvent was used to replace α-CD for breaking the micelles. For borate ion, a concept using a low flow-liquid junction interface in combination with the reduction of the electroosmotic mobility (EOF) by capillary coating was adopted so that borate would not enter the ESI source and suppress the signal generated by the analyte. With these approaches, significant better S/N ratios were obtained in comparison with the earlier CE-MS results.

並列關鍵字

Ganglioside ； Capillary Coating ； Borate ； Cyclodextrin

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