Tri N, Caldwell K, Beckett R
Water Studies Centre, Monash University, Clayton, Australia.
Anal Chem. 2000 Apr 15;72(8):1823-9. doi: 10.1021/ac990822i.
Electrical field-flow fractionation (ElFFF) results for a series of polystyrene latex beads are presented. To first approximation, retention behavior can be related to conventional FFF theory, modified to account for a particle-wall repulsion effect. Size selectivity and column efficiency were exceptionally high, again approaching the upper limit predicted by theory. For the channel described in the present study, application of small voltages (typically less than 2 V) across the thin (131 microm) separation space defined by a Teflon spacer generates nominal field strengths of 10(4) V m(-1). However, electrode polarization reduces the effective field across the bulk of the channel to approximately 3% of the nominal value in the system studied. The magnitude of the applied field was calibrated by using standard latex beads of known size and mobility. Perturbations to retention behavior, such as overloading, were investigated. It was found that ideal separations occur at very dilute concentrations of the sample plug and that working in systems of very low ionic strength, the double-layer thickness adds significantly to the effective size of a particle. Steric inversion was observed at a particle size of approximately 0.4 microm under the conditions employed.
给出了一系列聚苯乙烯胶乳珠的电场流分级（ElFFF）结果。初步估算，保留行为可与传统的场流分级理论相关，该理论经修正以考虑颗粒 - 壁面排斥效应。尺寸选择性和柱效极高，再次接近理论预测的上限。对于本研究中描述的通道，在由聚四氟乙烯垫片定义的薄（131微米）分离空间上施加小电压（通常小于2 V）会产生10⁴ V m⁻¹的标称场强。然而，在研究的系统中，电极极化将通道主体中的有效场强降低至标称值的约3%。通过使用已知尺寸和迁移率的标准胶乳珠校准施加场的大小。研究了对保留行为的干扰，如过载。发现理想的分离在样品塞的非常稀浓度下发生，并且在非常低离子强度的系统中工作时，双层厚度显著增加了颗粒的有效尺寸。在所采用的条件下，在粒径约为0.4微米时观察到了空间反演。
