Brunel Institute for Bioengineering, Brunel University West London, Uxbridge, Middlesex UB8 3PH, UK.
J Chromatogr A. 2011 Aug 5;1218(31):5108-14. doi: 10.1016/j.chroma.2011.05.078. Epub 2011 May 27.
Unlike the existing 2-D pseudo-ring model for helical columns undergoing synchronous type-J planetary motion of counter-current chromatograph (CCC), the 3-D "helix" model developed in this work shows that there is a second normal force (i.e. the binormal force) applied virtually in the axial direction of the helical column. This force alternates in the two opposite directions and intensifies phase mixing with increasing the helix angle. On the contrary, the 2-D spiral column operated on the same CCC device lacks this third-dimensional mixing force. The (principal) normal force quantified by this "helix" model has been the same as that by the pseudo-ring model. With β>0.25, this normal centrifugal force has been one-directional and fluctuates cyclically. Different to the spiral column, this "helix" model shows that the centrifugal force (i.e. the hydrostatic force) does not contribute to stationary phase retention in the helical column. Between the popular helical columns and the emerging spiral columns for type-J synchronous CCC, this work has thus illustrated that the former is associated with better phase mixing yet poor retention for the stationary phase whereas the latter has potential for better retention for the stationary phase yet poor phase mixing. The methodology developed in this work may be regarded as a new platform for designing optimised CCC columns for analytical and engineering applications.
与现有的用于反相色谱（CCC）同步型-J 行星运动的二维伪环模型不同，本工作中开发的三维“螺旋”模型表明，螺旋柱实际上存在第二个法向力（即副法向力）。随着螺旋角的增加，该力在两个相反方向上交替作用，从而加强了相间混合。相反，在相同的 CCC 装置上运行的二维螺旋柱缺乏这种三维混合力。该“螺旋”模型量化的（主）法向力与伪环模型的法向力相同。当 β>0.25 时，该法向离心力呈单向周期性波动。与螺旋柱不同，该“螺旋”模型表明离心力（即静压力）不会导致螺旋柱中固定相保留。在流行的螺旋柱和新兴的用于同步型-J 的螺旋柱之间，本工作说明了前者与更好的相间混合相关，但固定相保留较差，而后者具有更好的固定相保留潜力，但相间混合较差。本工作中开发的方法可被视为用于分析和工程应用的优化 CCC 柱设计的新平台。
