Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW, Australia.
Thermo Fisher Scientific, Manor Park, Tudor Road, Runcorn, UK.
J Chromatogr A. 2014 Mar 28;1335:122-35. doi: 10.1016/j.chroma.2013.08.004. Epub 2013 Aug 6.
The variation in mobile phase velocity as a function of the column radius has been shown to be a major limitation in the efficiency of HPLC columns. One contributing factor to the variability in the flow velocity stems from the heterogeneity in the radial packing density, leading to what has been described as the 'wall-effect'. The wall-effect generates parabolic-type elution profiles, which dilutes the sample and creates tailing bands. In this communication a new column technology is discussed that has been designed to overcome the wall effect, minimising the limitations associated with packing heterogeneity. This technology has been referred to as active flow technology and consists of two types of column designs, parallel segmented flow and curtain flow. In both these column designs sample that elutes through the column in the radial central region of the bed is separated from the flow that elutes along the wall region. Hence, the sample that elutes through the most efficiently packed region of the bed is collected to the detector. As a consequence more theoretical plates are obtained, and sensitivity is increased since the sample is not diluted by the diffuse tail. Sensitivity is enhanced further in the curtain flow design. The benefits of these new columns are discussed.
作为函数的列半径的流动相速度的变化已被证明是高效液相色谱柱的一个主要限制。造成流速的可变性的一个因素源于径向填充密度的非均一性，导致了所谓的“壁效应”。壁效应产生抛物线型洗脱曲线，稀释样品并产生拖尾带。在本通讯中讨论了一种新的柱技术，该技术旨在克服壁效应，最小化与填充不均匀性相关的限制。该技术被称为主动流动技术，由两种类型的柱设计组成，即平行分段流动和幕流。在这两种柱设计中，通过床层径向中心区域洗脱的样品与沿壁区域洗脱的流动相分离。因此，洗脱通过床层最有效填充区域的样品被收集到检测器。结果，获得了更多的理论塔板数，并且由于样品没有被弥散的尾部稀释，因此灵敏度提高。在幕流设计中，灵敏度进一步提高。讨论了这些新柱的优点。
