微胞電層析質譜分析磺胺類藥物靈敏度提升之研究

Abstract

為了減少界面活性劑對分析物於電灑法質譜偵測之抑制，本研究利用先前實驗室已開發的低流速鞘流-液體結合式界面銜接微胞電動毛細管電層析-電灑法質譜 (MEKC-ESI/MS) 分析九種磺胺類藥物。在pH 5.5的條件下，由於電滲流速度小於微胞自身的淌度，因此微胞會持續後退而減少界面活性劑引入之影響。而補償溶液槽中能夠提供往回補充的微胞，以維持微胞電層析的分離效率; 然而兩種和微胞作用力較強的磺胺類藥物在分離管柱中會隨著微胞往後帶而無法到達質譜端偵測， 因此只得到七種磺胺藥的分離結果。而在pH 6.2的條件之下，此時電滲流速度大於微胞自身的淌度，微胞會隨著電滲流帶往質譜端，因此利用前段銜接管的部份減少界面活性劑對質譜偵測的影響，於補償溶液槽及銜接管中溶液添加有機相甲醇使得電滲流速度減慢至小於微胞後退的速度，以減少界面活性劑的引入。由於微胞是持續由後方緩衝溶液槽中往前帶的，因此分離管柱仍保持完整的微胞區帶。在此條件下可以觀測到九種磺胺藥完整的分離結果。和利用低流速鞘流界面直接銜接MEKC-ESI/MS分析的結果比較，不僅能夠減少界面活性劑的抑制以提升分析物訊號的靈敏度，同時也能夠保持原有的分離效率。

To reduce the introduction of nonvolatile surfactants into the ESI source, a low flow-liquid junction interface was utilized in the MEKC-ESI/MS analysis of nine sulfonamides. Under pH 5.5 while the micelles would flow toward the inlet reservoir, the micelle in the junction could flow into the column, thus the separation efficiency could be maintained. However, separation of only seven sulfonamides could be observed. Since two sulfonamides whose binding forces with micelles are so strong that they could not be detected. Changing pH to 6.2, the EOF is faster than the mobility of micelle, thus all the nine sulfonamides could be detected. To avoid the micelle flow to the ESI source, organic solvent was added to the junction and the connecting capillary. With this arrangement, the EOF was reduced and the micelles would flow into the junction. In Comparison with the analyses using a low flow interface, this method provides better sensitivity.