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Visualizing and studying frictional heating effects in reversed-phase liquid chromatography using infrared thermal imaging
Analytica Chimica Acta ( IF 6.2 ) Pub Date : 2018-08-01 , DOI: 10.1016/j.aca.2018.02.061
Alexey A. Makarov , Benjamin F. Mann , Erik L. Regalado , Gregory F. Pirrone , Cheng Sun , Shuwen Sun , Timothy Nowak , Heather Wang , Ian Mangion

Column temperature control is a fundamental component of liquid chromatography experiments. However, it is typically monitored indirectly by tracking the temperature of an adjacent heating element that exchanges heat with the column in a controlled environment. The practice of not directly measuring the column temperature means that uncontrolled contributions of heat, such as frictional heating inside the column, can be overlooked. The present work describes the use of a high-resolution infrared thermal imaging camera to directly measure the column heat map during mobile phase flow. The approach was used to measure the longitudinal temperature gradient formed with three common mobile phases: water, methanol, and acetonitrile, in two 50 mm reversed-phase columns, a 1.7 μm particle-packed column and a polystyrene divinylbenzene monolith. In a close approximation to an adiabatic environment, the temperature gradients (ΔT) observed with the 1.7 μm particle column at a linear velocity of 5.8 mm/s were up to +16.6 and + 12.8 °C above an ambient temperature of 23 °C for water and acetonitrile, respectively. In the case of water, the measured temperature gradient values (ΔT) were within 1% difference of theoretically-calculated values and on average within 10% for acetonitrile. By contrast, the ΔT observed in the monolith was negligible. The elevated temperatures that are generated through friction in sub-2 μm particle columns may be particularly important to consider for the design of experiments that measure structural features of temperature-sensitive analytes, such as biomolecules. While frictional heating is one important application of the thermal imaging approach described, the technique can be used to provide a data-rich profile of heat exchange in numerous experimental configurations, chromatographic or otherwise.

中文翻译:

使用红外热成像对反相液相色谱中的摩擦热效应进行可视化和研究

柱温控制是液相色谱实验的基本组成部分。然而,它通常是通过跟踪在受控环境中与色谱柱交换热量的相邻加热元件的温度来间接监测的。不直接测量色谱柱温度的做法意味着可以忽略不受控制的热量贡献,例如色谱柱内部的摩擦加热。目前的工作描述了使用高分辨率红外热像仪在流动相流动过程中直接测量色谱柱热图。该方法用于测量由三种常见流动相(水、甲醇和乙腈)在两个 50 mm 反相柱、一个 1.7 μm 颗粒填充柱和聚苯乙烯二乙烯基苯整体中形成的纵向温度梯度。在非常接近绝热环境的情况下,使用 1.7 μm 颗粒色谱柱以 5.8 mm/s 的线速度观察到的温度梯度 (ΔT) 在 23 °C 的环境温度下高达 +16.6 °C 和 +12.8 °C分别是水和乙腈。在水的情况下,测得的温度梯度值 (ΔT) 与理论计算值的差异在 1% 以内,而对于乙腈,平均在 10% 以内。相比之下,在整料中观察到的 ΔT 可以忽略不计。在测量温度敏感分析物(如生物分子)的结构特征的实验设计中,亚 2 μm 颗粒色谱柱中通过摩擦产生的升高的温度可能特别重要。虽然摩擦加热是所描述的热成像方法的一项重要应用,
更新日期:2018-08-01
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