Cottet H, Gareil P, Viovy J L
Laboratoire d'Electrochimie et de Chimie Analytique, Ecole Nationale Supérieure de Chimie de Paris, France.
Electrophoresis. 1998 Sep;19(12):2151-62. doi: 10.1002/elps.1150191219.
This work focuses on the separation of standard polystyrenesulfonates (PSS), with molecular masses (Mr) between 16 and 990 x 10(3) in capillaries filled with semidilute (entangled) linear hydrophilic polymers. Contrary to cross-linked chemical gels, which produce permanent networks, solutions of linear polymers lead to dynamic networks. The analytical performances and migration mechanisms are discussed on the basis of experiments performed in solutions of linear polyethyleneoxides and derivatized celluloses of various molecular masses. The influence of the mesh size and of the lifetime of the obstacles of the separating network has been investigated in detail. The mesh size is assimilated to the blob size of the separating polymer and is a decreasing function of its concentration. The lifetime of the obstacles of the network, identified with the reptation time of the polymer chain, characterizes its dynamics. This characteristic time increases with both the molecular weight of the separating polymer and its concentration. Its impact was first examined at fixed blob size. Then, the influence of the blob size was studied while keeping the reptation time of the network constant. By doing so, the existence of interactions between the solute and the separating polymer or between the solute and capillary wall can be more safely assessed. It appears that the reptation time of the mesh has a large influence on the electrophoretic mobility of the PSSs under a threshold value, which is of the order of magnitude of the time taken by the PSS to migrate on the blob size. Also shown are separations using networks made up with mixtures of polyethyleneoxides of the same nature and same mass concentration, but of very different molecular masses. This latter approach allows one to adapt the viscosity of the solution and the dynamics of the network, keeping the blob size constant.
这项工作聚焦于在填充有半稀（缠结）线性亲水性聚合物的毛细管中分离分子量（Mr）在16至990×10³之间的标准聚苯乙烯磺酸盐（PSS）。与产生永久网络的交联化学凝胶不同，线性聚合物溶液会形成动态网络。基于在各种分子量的线性聚环氧乙烷和衍生化纤维素溶液中进行的实验，讨论了分析性能和迁移机制。详细研究了分离网络的网孔尺寸和障碍物寿命的影响。网孔尺寸被等同于分离聚合物的链段尺寸，并且是其浓度的递减函数。网络障碍物的寿命与聚合物链的蠕动时间相关，表征了其动力学特性。这个特征时间随着分离聚合物的分子量及其浓度的增加而增加。首先在固定链段尺寸下研究了其影响。然后，在保持网络蠕动时间恒定的同时研究了链段尺寸的影响。通过这样做，可以更可靠地评估溶质与分离聚合物之间或溶质与毛细管壁之间相互作用的存在情况。结果表明，在一个阈值以下，网孔的蠕动时间对PSS的电泳迁移率有很大影响，该阈值的量级与PSS在链段尺寸上迁移所需的时间相当。还展示了使用由相同性质、相同质量浓度但分子量差异很大的聚环氧乙烷混合物构成的网络进行的分离。后一种方法可以在保持链段尺寸恒定的情况下调整溶液的粘度和网络的动力学特性。
