Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences-Chemistry, University of Tasmania, Hobart, TAS, Australia 7001.
Australian Institute for Bioengineering and Biotechnology (AIBN), University of Queensland, Brisbane, Queensland, Australia.
J Chromatogr A. 2021 Nov 8;1657:462553. doi: 10.1016/j.chroma.2021.462553. Epub 2021 Sep 15.
We describe the chromatographic and electrochromatographic separation of small neutral and charged analytes using a fused silica capillary with a stationary pseudophase semi-permanent coating of didodecyldimethyl ammonium bromide (DDAB) aggregates. The coating was prepared by flushing the capillary with a DDAB solution that was rinsed out with the mobile phase. Our studies (i.e., electroosmotic flow measurements by capillary electrophoresis, chromatographic retention of a neutral probe and atomic force microscopy) suggested the formation of DDAB patchy admicelle, complete admicelle, or larger aggregates at the solid surface - liquid interface inside the capillary, depending on the concentration of DDAB used in coating the capillary. The analytical figures of merit for open tubular liquid chromatography (OT-LC, pressure driven) and open tubular capillary electrochromatography (OT-CEC, voltage driven) using a capillary coated with 0.5 mM DDAB and mobile phase/background solution of 25 mM borate buffer at pH 9.5 with 10% MeOH were the following: LOD = 3.0-5.0 µg/mL (OT-LC) and 2.5-5.0 µg/mL (OT-CEC); linearity R2 > 0.99 (peak area (OT-LC) and corrected peak area (OT-CEC)), intraday and interday repeatability%RSD < 5% (n = 12) for retention/migration time, peak area (OT-LC) and corrected peak area (OT-CEC). The reversed-phase and anion-exchange property of the stationary pseudophase was studied by the addition of organic solvents and sodium chloride to the mobile phase, respectively. We also demonstrate the increase in the ks of the tested analytes by implementing successive multiple ionic layer (SMIL) coating strategies with DDAB in combination with a cationic and/or anionic polyelectrolyte. The use of a stationary pseudophase coating is potentially an easy alternative way to conduct open-tubular liquid chromatography and electrochromatography.
我们描述了使用带有二癸基二甲基溴化铵（DDAB）聚集体固定相伪固定相的熔融石英毛细管对小中性和带电分析物的色谱和电色谱分离。该涂层是通过用 DDAB 溶液冲洗毛细管而制备的，然后用流动相冲洗掉。我们的研究（即通过毛细管电泳测量电渗流，中性探针的色谱保留和原子力显微镜）表明，取决于用于涂覆毛细管的 DDAB 浓度，在毛细管内的固-液界面处形成了 DDAB 斑片状胶束、完整胶束或更大的聚集体。使用 0.5 mM DDAB 涂覆的毛细管和流动相/背景溶液（25 mM 硼酸缓冲液，pH 9.5，含 10％甲醇）进行开管液相色谱（压力驱动）和开管毛细管电色谱（电压驱动）的分析性能如下：LOD = 3.0-5.0 µg/mL（OT-LC）和 2.5-5.0 µg/mL（OT-CEC）；线性度 R2 > 0.99（峰面积（OT-LC）和校正峰面积（OT-CEC）），日内和日间重复性%RSD < 5％（n = 12），保留/迁移时间，峰面积（OT-LC）和校正峰面积（OT-CEC）。通过向流动相中分别添加有机溶剂和氯化钠，研究了固定相伪固定相的反相和阴离子交换性质。我们还通过使用 DDAB 与阳离子和/或阴离子聚电解质结合的连续多离子层（SMIL）涂层策略，证明了测试分析物的 ks 值增加。使用固定相伪固定相涂层可能是进行开管液相色谱和电色谱的一种简单替代方法。
