Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa.
Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa.
Anal Chim Acta. 2020 Apr 22;1107:225-232. doi: 10.1016/j.aca.2020.02.033. Epub 2020 Feb 18.
Thermal field-flow fractionation (ThFFF) was successfully coupled online to size exclusion chromatography (SEC) in a comprehensive two-dimensional configuration. In the first dimension, fractionation according to chemical composition based on the interplay of thermal and translational diffusion took place in the ThFFF channel. Fractions from the first dimension were comprehensively transferred to the second dimension, SEC, and separated according to hydrodynamic volume which is a function of molar mass. To illustrate the capabilities of this novel two-dimensional fractionation approach, polystyrene-poly (methyl methacrylate) block copolymers were comprehensively fractionated and characterized. Blends of homopolymers, homo- and copolymers, and copolymers with different compositions were fractionated and the effects of experimental conditions, the components' molar masses and compositions were investigated. The results illustrated the molar mass independence of the thermal diffusion coefficient in ThFFF. Translational diffusion coefficients were quantitatively determined via dynamic light scattering. The study aimed at proving the versatility of the comprehensive online coupling of ThFFF and SEC for the analysis of complex polymers having the ability to provide detailed molecular information (chemical composition and molar mass distribution) as well thermal and translational diffusion information in a single analysis. Finally, the merits of using information-rich detectors are highlighted.
热场流分级（ThFFF）与尺寸排阻色谱（SEC）在线成功地耦合在二维全面配置中。在第一维中，根据热扩散和迁移扩散相互作用的化学组成进行分级，在 ThFFF 通道中进行。第一维的馏分被全面转移到第二维，SEC，并根据摩尔质量的函数——流体力学体积进行分离。为了说明这种新型二维分级方法的能力，对聚苯乙烯-聚（甲基丙烯酸甲酯）嵌段共聚物进行了全面的分级和表征。对均聚物、均聚物和共聚物的混合物以及具有不同组成的共聚物进行了分级，并研究了实验条件、各组分的摩尔质量和组成的影响。结果表明，ThFFF 中的热扩散系数与摩尔质量无关。通过动态光散射定量测定了迁移扩散系数。该研究旨在证明 ThFFF 和 SEC 的全面在线耦合用于分析复杂聚合物的多功能性，这种方法具有在单次分析中提供详细分子信息（化学组成和摩尔质量分布）以及热扩散和迁移扩散信息的能力。最后，突出了使用信息丰富的检测器的优点。
