| Summary: | 碩士 === 國立中正大學 === 化學所 === 98 === In pharmaceutics, simultaneous separation of multiple active ingredients of drugs in a single analysis is getting important for patients with multiple symptoms. In this work, a novel stationary phase of supercritical fluid chromatography (SFC) was developed by covalently bonding 1-vinylbenzyl-4-butylimidazole (VBBI) and divinylnonanalimidazole (C9(vim)2) to silica particles. Then, the functionalized silica particles was employed to prepare the packed ionic liquid-functionalized column. This type of column offers the multiple modes of molecular-interactions to create highly selective stationary phase for chromatography and was employed for simultaneous separation of different types of active ingredients. The parameters effect on the SFC separation were examined and optimized. The data indicate that the separation mechanism of this column appears to involve multiple interactions, including electrostatic, hydrophobic, hydrogen bonding, and π-π interactions. The multiple-modes interaction enables the effective separation of acidic, basic and neutral drugs by SFC simultaneously. The multiple-modes interaction gave better separation performance, as compared this column with other commercial columns for the separation of acidic, basic, and neutral compounds.
This study also examined the column efficiency of a sub-2-μm particles packed column in supercritical fluid chromatography. The need for greater speed and efficiency in various applications has driven the advent of the column with sub-2-μm particles to improve the separation efficiency of high performance liquid chromatographic. However, the cost of sub-2-μm particles column increases the back pressure, due to the use of high viscosity of the liquid phase as the mobile phase. This results in the introduction of a new generation of liquid chromatographic equipment: ultra-high performance liquid chromatography (UPLC). Carbon dioxide supercritical fluid chromatography can capitalize on the intrinsic low viscosity and high diffusivity of supercritical carbon dioxide. It reduces the column back pressure that leads to the feasibility of using sub-2-μm particles column in SFC system to increase the separation efficiency.
To understand the separation efficiency of the sub-2-μm particles packed column in traditional SFC system, this work compared the separation efficiency of 1.8 and 5 μm particles packed columns in SFC. The minimum theoretical plate heights are 26.1 μm (at 0.6 mL / min. flow rate) and 28.9 μm (at 1.5 mL / min. flow rate) for 1.8 and 5 μm particles columns, respectively. The results indicate the use of small particles column did not increase the separation efficiency significantly as that of theoretical expectation. Further analysis the experimental data of the sub-2-μm particles column indicates that the traditional instrument system has large bandwidth contribution from extracolumn. Also the effect of extracolumn on bandwidth was reduced with small internal diameter tubing. However, it led to high backpressure from small internal diameter tubing. Therefore, the SFC system also requires optimization for using sub-2-μm particles column to obtain high separation efficiency.
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