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  • 學位論文

應用離子液體於分散液相液相微萃取及維他命分離 (1)利用離子液體分散液液微萃取搭配毛細管電泳萃取帶電荷物質 (2)利用離子液體管柱搭配超臨界流體層析分離維他命

Application of Ionic Liquids on The DLLME and Vitamins Separation: (1) IL-DLLME for The Determination of Four Charge Analytes with CE (2) Using Ionic Liquid Column to Separation Vitamins with SFC

指導教授 : 魏國佐
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摘要


在綠色化學的領域中,離子液體 (Ionic liquid, IL) 扮演了重要的角色,其具有高熱穩定性、高導電度、低熔點及低蒸氣壓等特性,可取代傳統的揮發性有機溶劑,而被視為一種綠色溶劑。離子液體用途極廣,可應用於萃取、靜相合成、催化、電化學等多種領域。 本研究第一部份利用 IL 於分散液相-液相微萃取 (Dispersive liquid-liquid microextraction, DLLME),此技術具有高濃縮倍數及萃取時間短之優點,且可改善使用傳統高毒性有機溶劑當萃取劑的缺點,加上利用 IL 的離子對 (ion-pair) 效應能萃取帶電荷物質;並搭配使用毛細管電泳 (Capillary electrophoresis, CE) 進行分離測定,可運用於多種物質檢測上。實驗結果顯示在最佳化條件下,可於 7 分鐘內成功分離四種帶電荷物質,並於緩衝溶液中添加β-環糊精(β-cyclodextrin) 改善帶電荷分析物因電分散而產生的前伸 (fronting) 現象;此萃取方法的偵測極限可達 0.83 ppm,定量極限可達 2.77 ppm 同日間再現性小於 5.29 % 異日間再現性小於 8.90 %,濃縮倍數達 117 倍。 本研究第二部分是利用實驗室專為超臨界流體層析 (Supercritical fluid chromatography, SFC) 所開發的離子液體管柱,分離棕櫚油中四種維他命 E異構物、脂溶性維他命及水溶性維他命。實驗上篩選適當的靜相後,改變有機溶劑添加量、管柱壓力、及管柱溫度得到最佳分離條件後;結果顯示 Silpyvcbs 管柱可於 18 分鐘內有效分離棕櫚油中四種維他命 E 異構物,其線性相關係數 (R2) 達 0.9981,且偵測極限可達 0.55 ppm,並利用面積歸一法,推算出樣品中四種異構物的相對含量與文獻比較;此外該管柱也可以成功分離 E、D3、K1、A 四種脂溶性維他命。SFC分離時動相大多使用非極性超臨界二氧化碳,因此對於分離高水溶性分析物較為困難,經由實驗發現,離子液體管柱 Silprbipy-BS,可以用來分離水溶性維他命 B1、B2、B3、B6,在最佳化條件下可於30 分鐘內分離。

並列摘要


Ionic liquids (ILs) have been playing important roles in green chemistry. Ionic liquid (IL) has several unique properties, such as high thermal stability, high conductivity, low melting point, and low vapor pressure characteristics that can replace traditional volatile organic solvents. Therefore, they are considered as green solvents. In analytical applications, ILs have been used in chromatography, mass spectrometry, electrochemistry, extraction, etc. In the first part of this study, we used ionic liquid to develop a simple, rapid, and efficient extraction method, ionic liquid dispersived liquid-liquid microextraction (IL-DLLME), for the first time to determine charged analytes ([Ru(bpy)3]Cl2, acid orange 7 (AO7), methyl orange (MO), and bromothymol blue (BB)) in aqueous phase. The ion-pair behavior of 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) permits the extraction of these charged compounds from the aqueous matrix and also allowing their preconcentration to enhance the sensitivity. The analysis of the extracted compounds was performed by capillary electrophoresis (CE) coupled with diode array detection (DAD). Under the optimal conditions, CE can successfully separate these analytes in 7 min. It is worth to know that we added beta-cyclodextrin to the running buffer of CE to improve the fronting phenomenon of charged analytes. Linearities of the calibration curves are at the range of 25-2000 ppm. Coefficient of correlation (R2) ranges from 0.9728 to 0.9992. Detection limits are between 0.83 and 2.56 ppm. The enrichment factors of analytes are in the range of 78 to 117. The intra-day RSD and inter-day RSD of area are 2.70 % to 5.69 % and 7.04 % to 8.9 %, respectively For the second part of this study, we used the ionic liquid column to separate vitamin E isomers (α-tocopherol, α-tocotrienol, γ-tocotrienol, δ-tocotrienol) of palm oil, fat-soluble vitamins, and water-soluble vitamins. The column screening results show that the Silpyvcbs column can effectively separate vitamin E isomers of palm oil in 18 minutes. The linear correlation coefficient (R2) of α-tocopherol is 0.9981. The detection limit is about 0.55 ppm. In addition, the area normalization method was used to estimate the relative content of each isomer and compared with literature. Silpyvcbs column was also extended to the separation of fat-soluble vitamins. In SFC, the mobile phase uses non-polar carbon dioxide. It is normally difficult to separate highly polar or highly water-soluble solutes. To demonstrate the potential of IL columns, Silprbipy-BS was explored to separate water-soluble vitamins. The preliminary results indicate that the separation of water soluble vitamin with SFC is feasible, but the efficiency is poor. It requires furhter work to separate a mixture of water-soluble and oil-solube vitamins at the same time.

並列關鍵字

charge analytes SFC DLLME vitamins

參考文獻


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