聚丙烯酰胺中刚性亚微米级颗粒的毛细管区带电泳。溶液选择性、峰展宽和分离度

Capillary zone electrophoresis of rigid submicron-sized particles in polyacrylamide. Solution selectivity, peak spreading and resolution.

作者信息

Radko S P, Chrambach A

机构信息

Section on Macromolecular Analysis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1580, USA.

出版信息

J Chromatogr A. 1999 Jul 2;848(1-2):443-55. doi: 10.1016/s0021-9673(99)00456-2.

DOI:10.1016/s0021-9673(99)00456-2

PMID:10427764

Abstract

Submicron-sized rigid particles can be separated in a size-dependent fashion by electrophoresis in free solution. Yet it has remained unknown whether the presence of polymers in the solution confers an advantage in size-dependent separation of submicron particles and their resolution. The present study addresses that question, using capillary zone electrophoresis of carboxylate modified polystyrene latex microspheres of 55, 140 and 215 nm radius in solutions of linear polyacrylamide in the M(r) range of 0.4.10(6) to 1.14.10(6). Selectivity of particle separation increases in direct relation to the polymer concentration in the concentration range of 0 to 1% (w/v). Selectivity was found to increase with M(r) of the polymer for the particle sets of 55/140 (nm/nm) and 140/215 (nm/nm) but to decrease with polymer M(r) for the 55/215 (nm/nm) set. Peak spreading is a complex and, in the case of the largest particle, non-monotonic function of polymer concentration, with a minimum at concentrations around the entanglement threshold, c*. Consequently, resolution of the 55/215 and 140/215 (nm/nm) sets also exhibits a maximum around the entanglement threshold while resolution for the 55/140 (nm/nm) set increases with a rise of polymer concentrations above c*. Within the range of optimally resolving polymer concentrations there also occurs a maximum of resolution for all particle sets at a field strength in the range of 150 to 250 V cm-1.

摘要

亚微米级刚性颗粒可通过自由溶液中的电泳以尺寸依赖的方式进行分离。然而，溶液中聚合物的存在是否能在亚微米颗粒的尺寸依赖分离及其分辨率方面带来优势，这一点仍不明确。本研究通过在分子量范围为0.4×10⁶至1.14×10⁶的线性聚丙烯酰胺溶液中，对半径为55、140和215nm的羧酸盐改性聚苯乙烯胶乳微球进行毛细管区带电泳，来解决这个问题。在0至1%（w/v）的浓度范围内，颗粒分离的选择性与聚合物浓度直接相关。对于55/140（nm/nm）和140/215（nm/nm）的颗粒组，发现选择性随聚合物的分子量增加而增加，但对于55/215（nm/nm）的颗粒组，选择性随聚合物分子量的增加而降低。峰展宽是一个复杂的过程，对于最大的颗粒而言，它是聚合物浓度的非单调函数，在浓度接近缠结阈值c时达到最小值。因此，55/215和140/215（nm/nm）颗粒组的分辨率在缠结阈值附近也呈现最大值，而55/140（nm/nm）颗粒组的分辨率则随着聚合物浓度高于c而增加。在最佳分辨聚合物浓度范围内，所有颗粒组在150至250V cm⁻¹的场强下也会出现分辨率的最大值。