Laboratorio de Investigación y Desarrollo de Métodos Analíticos (LIDMA) and División Química Analítica, Facultad de Ciencias Exactas, UNLP, 47 y 115 (B1900AJL), La Plata, Argentina.
J Chromatogr A. 2020 Jul 5;1622:461127. doi: 10.1016/j.chroma.2020.461127. Epub 2020 Apr 18.
Gas chromatographic columns based on ionic liquids (ILs) are very promising since the selectivity of these columns can be tuned by both the cation and the anion chemical nature. In this paper, efficiencies of capillary columns based on four phosphonium ionic liquids were studied. The performance of seven columns containing the cation trihexyl(tetradecyl)phosphonium and the anions bromide, chloride, and bis(trifluoromethylsulfonyl)imide was evaluated by measuring the solute band broadening as a function of gas velocities at three temperatures. Hence, classical height equivalent to a theoretical plate (H) against gas velocity (u) plots corresponding to those columns were generated and the data were fitted to the Golay-Guiochon equation with the aim of seeking the optimum conditions to be operated each of them. Band broadening at practical gas velocities is mainly due to poor mass transfer properties of solutes in the (viscous) liquid phases, which limits the achieved efficiencies. These H/u plots proved to be necessary to characterize the column quality at a given temperature, to interpret the band broadening phenomena and thus, to establish the lower temperature limits and the expected plate counts at that temperature.
基于离子液体（ILs）的气相色谱柱非常有前途，因为这些柱子的选择性可以通过阳离子和阴离子的化学性质来调节。本文研究了基于四种膦离子液体的毛细管柱的效率。通过测量在三种温度下溶质带展宽随气体速度的变化，评估了含有阳离子三己基（十四烷基）膦和阴离子溴化物、氯化物和双（三氟甲基磺酰基）亚胺的七种柱的性能。因此，生成了对应于这些柱的经典高度相当于理论板（H）与气体速度（u）的图，并将数据拟合到 Golay-Guiochon 方程，以寻求每种柱操作的最佳条件。在实际气体速度下的带宽展宽主要是由于溶质在（粘性）液相中的较差传质性质，这限制了实现的效率。这些 H/u 图对于在给定温度下表征柱质量、解释带宽展宽现象以及确定该温度下的较低温度限制和预期的板数是必要的。
