Baalousha M, Kammer F V D, Motelica-Heino M, Hilal H S, Le Coustumer P
University of Bordeaux 1, Center of Development of Applied Geology, Avenue des Facultés, 33400 Talence, France.
J Chromatogr A. 2006 Feb 3;1104(1-2):272-81. doi: 10.1016/j.chroma.2005.11.095. Epub 2005 Dec 19.
Flow-field flow fractionation (FlFFF) coupled to multi-angle laser light scattering (MALLS) was evaluated for size and shape determination of standard spherical and arbitrarily shaped natural colloids. Different fitting methods for light scattering data retrieved from MALLS were evaluated to determine the particle size of spherical standards and natural colloids. In addition, FlFFF was optimized for best fractionation in connection to MALLS, minimal colloids-membrane interaction, and minimal sample losses. FlFFF, calibrated with standard particles, was used to determine hydrodynamic diameter, or radius (D(h) or R(h)), of the fractionated colloids, whereas the MALLS was used to determine root mean square radius of gyration (R(g)) for fractionated colloids. Combining both results, by calculating the R(g)/R(h) ratio, allows an estimation of colloid deviation from the shape of homogeneous sphere. Accordingly, this study demonstrates that, FlFFF-MALLS is a valuable technique for characterizing heterogeneous and arbitrarily shaped natural colloidal particles in terms of size and shape. To check the usefulness of FlFFF-MALLS in natural colloid studies, the technique was used to investigate the sedimentation behavior of extracted soil colloidal particles. Results illustrate that, in a silty till sample, carbonates function as cement between the colloidal particles, and consequently, change their sedimentation behavior. On the other hand, carbonate dissolution generates a more homogeneous colloidal sample.
对流场流动分级法（FlFFF）与多角度激光光散射法（MALLS）联用进行标准球形和任意形状天然胶体的尺寸和形状测定评估。对从MALLS获取的光散射数据采用不同的拟合方法来确定球形标准物和天然胶体的粒径。此外，对FlFFF进行了优化，以实现与MALLS联用的最佳分级效果、最小化胶体与膜的相互作用以及最小化样品损失。用标准颗粒校准的FlFFF用于测定分级后胶体的流体动力学直径或半径（D(h)或R(h)），而MALLS则用于测定分级后胶体的均方根回转半径（R(g)）。通过计算R(g)/R(h)比值将两者结果相结合，可估算胶体与均匀球体形状的偏差。因此，本研究表明，FlFFF-MALLS是一种在尺寸和形状方面表征非均质和任意形状天然胶体颗粒的有价值技术。为检验FlFFF-MALLS在天然胶体研究中的实用性，该技术被用于研究提取的土壤胶体颗粒的沉降行为。结果表明，在粉质冰碛土样品中，碳酸盐起到胶体颗粒间胶结物的作用，从而改变其沉降行为。另一方面，碳酸盐溶解会产生更均匀的胶体样品。
