酸性緩衝溶液於毛細管電泳電灑法質譜儀之研究

簡邱堂(Chiu-Tang Chien)

指導教授 ： 何國榮

國立臺灣大學/理學院/化學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00716

摘要

毛細管電泳分離中包含許多重要的分離參數，緩衝溶液的種類對分離也有相當程度的影響，文獻指出分離條件為酸性條件下，磷酸根可以和毛細管管壁的矽醇基形成錯合物，因此利用磷酸緩衝溶液可以獲得較佳的解析度。電灑法是目前毛細管電泳/質譜儀最普遍被使用的游離方法，然而毛細管電泳所使用的緩衝溶液若使用非揮發性的緩衝溶液，會在離子化的過程與分析物相互競爭而抑制質譜訊號，所以大部分毛細管電泳電灑法質譜儀都是使用揮發性的緩衝溶液系統，如醋酸銨。

在酸性條件下，電滲流的速度降到相當低，因此緩衝溶液中的磷酸根陰離子流入質譜的量是非常少的，所以使用磷酸銨的緩衝溶液，並不會嚴重影響分析物的質譜訊號。在使用傳統鞘流界面時，鞘流溶液都會添加少量的有機酸，如甲酸或醋酸以增加分析物的游離化效率。這些有機酸會進入分離中的毛細管內，若用磷酸鹽類當緩衝溶液時，可能會影響到分離，但鞘流溶液中添加磷酸卻容易造成放電，質譜訊號也不穩定，因此無法兼顧分離及靈敏度，但若是使用本實驗室發展的低流速鞘流界面，因可以在鞘流溶液中加入少量的磷酸，使得在分離時較不受影響，並且可以得到穩定的質譜訊號和不錯的靈敏度

關鍵字

緩衝溶液 ； 毛細管電泳 ； 電灑法質譜儀

並列摘要

There are many factors affecting the separation including the composition of buffer in capillary electrophoresis(CE). It had be shown that phosphate proven better resolution in low pH was adsorbed to silica surface of column, thus converting silanol group to more easily protonated. Electrospray ionization(ESI) is the most common ionization techniques for capillary electrophoresis / mass spectrometry (CE/MS). Because non-volatile buffer suppressed the signal of analyte, volatile buffers such as ammonium acetate was commonly used in CE/MS.

In CE/MS, it was investigated that electroosmotic flow (EOF) was reduced in low pH. The amount of anions such as phosphate ions entering in MS were very small. Therefore, the signal of analyte could not be suppressed when using ammonium phosphate in CE/MS. But the organic acid such as formic acid or acetate acid added to sheath liquid were flowed in column and affect separation efficiency. However, The signal is not stable by adding phosphoric acid in sheath liquid when using sheath liquid interface. When using low flow interface, the well separation efficiency and acceptable signal was obtained by adding phosphoric acid in sheath liquid.

並列關鍵字

buffer ； capillary electrophoresis ； ESI

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