Lv Chunguang, Heiter Jaana, Haljasorg Tõiv, Leito Ivo
Institute of Chemistry, University of Tartu, Tartu, Estonia.
Institute of Chemistry, University of Tartu, Tartu, Estonia.
Anal Chim Acta. 2016 Aug 17;932:114-23. doi: 10.1016/j.aca.2016.05.026. Epub 2016 May 24.
A new method of reproducible preparation of vinylic polymeric monolithic columns with a key step of covalently anchoring the monolith to PEEK surface is described. In order to chemically attach the polymer monolith to the tube wall, methacrylate functional groups were introduced onto PEEK surface by a three-step procedure, including surface etching, surface reduction and surface methacryloylation. The chemical state of the modified tubing surface was characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy. It was found that the etching step is the key to successfully modifying the PEEK tubing surface. Poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermally initiated free radical copolymerization within the confines of surface-vinylized PEEK tubings of dimensions close to ones conventionally used in HPLC and UHPLC (1.6 mm internal diameter, 10.0-12.5 cm length). Adhesion test was done by measuring the operating pressure drop, which the prepared stationary phases can withstand. Good pressure resistance, up to 140 bar/10 cm (flow rate 0.5 mL min(-1), acetonitrile as a mobile phase), indicates strong bonding of monolith to the tubing wall. The monolithic material was proven to have a permeability of 1.7 × 10 (-14) m(2), applying acetonitrile-water 70:30 (v/v) as a mobile phase. The column performance was reproducible from column to column and was evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode (acetonitrile-water 70:30, v/v). The numbers of plates per meter at optimal flow rate were found to be between 26 000 and 32 000 for the different analytes.
描述了一种可重现地制备乙烯基聚合物整体柱的新方法，该方法的关键步骤是将整体柱共价锚定到聚醚醚酮（PEEK）表面。为了将聚合物整体柱化学连接到管壁上，通过三步程序将甲基丙烯酸酯官能团引入到PEEK表面，包括表面蚀刻、表面还原和表面甲基丙烯酰化。用衰减全反射红外（ATR-IR）光谱对改性管表面的化学状态进行了表征。发现蚀刻步骤是成功改性PEEK管表面的关键。通过热引发自由基共聚在尺寸接近高效液相色谱（HPLC）和超高效液相色谱（UHPLC）常规使用尺寸（内径1.6 mm，长度10.0 - 12.5 cm）的表面乙烯基化PEEK管内原位合成了聚（苯乙烯 - 二乙烯基苯）整体柱。通过测量所制备的固定相能够承受的操作压降进行附着力测试。高达140 bar/10 cm（流速0.5 mL min⁻¹，乙腈作为流动相）的良好耐压性表明整体柱与管壁之间有牢固的结合。以乙腈 - 水70:30（v/v）作为流动相时，证明整体材料的渗透率为1.7×10⁻¹⁴ m²。柱性能在不同柱之间具有可重复性，并通过反相模式（乙腈 - 水70:30，v/v）下一系列烷基苯的等度分离进行评估。对于不同的分析物，在最佳流速下每米的塔板数在26000至32000之间。
