McGettrick Julie R, Williamson Nathan H, Sutton Adam T, Palmer Christopher P
Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA.
Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia.
Electrophoresis. 2017 Mar;38(5):730-737. doi: 10.1002/elps.201600380. Epub 2016 Dec 20.
Electrokinetic chromatography (EKC) is a powerful analytical technique that uses an ionic pseudo-stationary phase (PSP) to separate neutral compounds. Although anionic surfactants are the most common choice for PSP, cationic latex nanoparticles are an attractive alternative. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize several types of diblock copolymers that self-assemble into latex nanoparticles, which were characterized by a variety of techniques including diffusion NMR. The performance of each nanoparticle as a PSP was studied by using a homologous series of ketones and linear solvation energy relationships (LSER) analysis. A cationic homopolymer coating was found to be necessary to prevent band broadening caused by analyte interactions with nanoparticles adsorbed to the capillary surface. No significant difference in methylene selectivity or LSER parameters was observed between nanoparticles with different cationic shells, but differences were observed between nanoparticles with different hydrophobic cores. Cationic latex nanoparticles behaved more like anionic latex nanoparticles than like cationic surfactants, suggesting that selectivity is primarily driven by the hydrophobic portion of a PSP. Cationic latex nanoparticles in combination with a homopolymer cationic capillary coating are an excellent choice for EKC analyses where an anodic electroosmotic flow is required.
电动色谱（EKC）是一种强大的分析技术，它使用离子型假固定相（PSP）来分离中性化合物。虽然阴离子表面活性剂是PSP最常见的选择，但阳离子乳胶纳米颗粒是一种有吸引力的替代物。采用可逆加成-断裂链转移（RAFT）聚合反应合成了几种类型的二嵌段共聚物，这些共聚物自组装成乳胶纳米颗粒，并通过包括扩散核磁共振在内的多种技术对其进行了表征。通过使用一系列同系物酮和线性溶剂化能关系（LSER）分析，研究了每种纳米颗粒作为PSP的性能。发现需要阳离子均聚物涂层来防止由于分析物与吸附在毛细管表面的纳米颗粒相互作用而导致的谱带展宽。在具有不同阳离子壳的纳米颗粒之间，未观察到亚甲基选择性或LSER参数有显著差异，但在具有不同疏水核的纳米颗粒之间观察到了差异。阳离子乳胶纳米颗粒的行为更类似于阴离子乳胶纳米颗粒，而不是阳离子表面活性剂，这表明选择性主要由PSP的疏水部分驱动。阳离子乳胶纳米颗粒与均聚物阳离子毛细管涂层相结合，是需要阳极电渗流的EKC分析的极佳选择。
