Food Colloids Group, Department of Food Technology, Engineering and Nutrition, Lund University, P.O. Box 124, SE-22100 Lund, Sweden.
J Chromatogr A. 2012 Aug 31;1253:120-6. doi: 10.1016/j.chroma.2012.07.029. Epub 2012 Jul 20.
Direct determination of hydrodynamic radius from retention time is an advantage of the field-flow fractionation techniques. However, this is not always completely straight forward since non-idealities exist and assumptions have been made in deriving the retention equations. In this study we investigate the effect on accuracy from two factors: (1) level of sophistication of the equations used to determine channel height from a calibration experiment and (2) the influence of secondary relaxation on the accuracy of hydrodynamic radius determination. A new improved technique for estimating the channel height from calibration experiments is suggested. It is concluded that severe systematic error can arise if the most common channel height equations are used and an alternative more rigorous approach is described. For secondary relaxation it is concluded that this effect increases with the cross-flow decay rate. The secondary relaxation effect is quantified for different conditions. This is part one of two. In the second part the determination of hydrodynamic radius are evaluated experimentally under similar conditions.
从保留时间直接确定流体力学半径是场流分离技术的一个优势。然而，这并不总是完全直接的，因为存在非理想情况，并且在推导保留方程时做了一些假设。在这项研究中，我们研究了两个因素对准确性的影响：（1）用于从校准实验确定通道高度的方程的复杂程度，以及（2）二次弛豫对流体力学半径确定准确性的影响。提出了一种新的改进的从校准实验中估计通道高度的技术。结论是，如果使用最常见的通道高度方程，会产生严重的系统误差，并且描述了一种替代的更严格的方法。对于二次弛豫，结论是这种影响随着横向流衰减率的增加而增加。对于不同的条件，对二次弛豫效应进行了量化。这是两部分中的第一部分。在第二部分中，在类似的条件下进行了实验评估流体力学半径的确定。
