University of Ottawa, Department of Physics, 150 Louis-Pasteur, Ottawa, ON K1N 6N5, Canada.
J Chromatogr A. 2014 Apr 25;1339:219-23. doi: 10.1016/j.chroma.2014.03.002. Epub 2014 Mar 13.
Hydrodynamic chromatography (HC) and field-flow fractionation (FFF) separation methods are often performed in 3D rectangular channels, though ideal retention theory assumes 2D systems. Devices are commonly designed with large aspect ratios; however, it can be unavoidable or desirable to design rectangular channels with small or even near-unity aspect ratios. To assess the significance of finite-aspect ratio effects and interpret experimental retention results, an ideal, analytical retention theory is needed. We derive a series solution for the ideal retention ratio of HC and FFF rectangular channels. Rather than limiting devices' ability to resolve samples, our theory predicts that retention curves for normal-mode FFF are well approximated by the infinite plate solution and that the performance of HC is actually improved. These findings suggest that FFF devices need not be designed with large aspect ratios and that rectangular HC channels are optimal when the aspect ratio is unity.
水动力色谱 (HC) 和场流分离 (FFF) 分离方法通常在 3D 矩形通道中进行，尽管理想的保留理论假设为 2D 系统。设备通常设计为具有大纵横比；然而，设计具有小纵横比甚至近单位纵横比的矩形通道可能是不可避免的或期望的。为了评估有限纵横比效应的重要性并解释实验保留结果，需要一种理想的分析保留理论。我们为 HC 和 FFF 矩形通道推导了理想保留比的级数解。我们的理论不是限制设备分离样品的能力，而是预测正常模式 FFF 的保留曲线可以很好地用无限板解近似，并且 HC 的性能实际上得到了提高。这些发现表明，FFF 设备不必设计为大纵横比，并且当纵横比为 1 时，矩形 HC 通道是最佳的。
