Micromachined GC columns for fast separation of organophosphonate and organosulfur compounds
Micromachined GC columns for fast separation of organophosphonate and organosulfur compounds
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DOI：
10.1021/ac800212e
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发表时间：
2008-06-01
影响因子：
7.4
通讯作者：
Cadwallader, Keith R.
中科院分区：
文献类型：
--
作者：
Radadia, Adarsh D.;Masel, Richard I.;Cadwallader, Keith R.
本文演示了如何制备用于有机膦酸酯和有机硫化合物分离的微型柱（微柱），其性能可与商业毛细管柱相媲美。使用氦气作为载气，以20 cm/s的速度，用3 m长OV-5涂覆的微柱产生约16500个理论塔板，相厚度为0.25 μ m。这一进展的关键是开发了适用于具有Pyrex顶部的硅微柱的失活程序。硅-Pyrex微柱中的活性位点引起峰拖尾和不需要的吸附。实验上，我们发现，有机硅氢化物失活降低吸附活性的微柱比硅氮烷和硅烷处理。但是在没有进一步处理的情况下，膦酸酯峰在涂覆过程之后继续拖尾。我们发现，用甲基膦酸频哪醇酯（PMP）热处理消除了膦酸酯峰拖尾。相比之下，使用N，O-双（三甲基甲硅烷基）乙酰胺、六甲基二硅氮烷和1-（三甲基甲硅烷基）咪唑的常规的甲硅烷基化不能消除峰拖尾。柱活性测试表明，PMP处理还改善了2，6-二甲基苯胺、1-辛醇和1-癸醇的峰，这意味着PMP处理降低了柱的氢键合位点。FT-IR分析表明，暴露于PMP形成一个键的固定相，失活的活性位点负责有机膦酸酯峰拖尾。
This article demonstrates how to prepare microfabricated columns (microcolumns) for organophosphonate and organosulfur compound separation that rival the performance of commercial capillary columns. Approximately 16 500 theoretical plates were generated with a 3 m long OV-5-coated microcolumn with a 0.25 mu m phase thickness using helium as the carrier gas at 20 cm/s. Key to the advance was the development of deactivation procedures appropriate for silicon microcolumns with Pyrex tops. Active sites in a silicon-Pyrex microcolumn cause peak tailing and unwanted adsorption. Experimentally, we found that organosilicon hydride deactivation lowers adsorption activity in microcolumns more than silazane and silane treatments. But without further treatment, the phosphonate peaks continue to tail after the coating process. We found that heat treatment with pinacolyl methylphosphonic acid (PMP) eliminated the phosphonate peak tailing. In contrast, conventional resilylation employing N,O-bis(trimethylsilyl)acetamide, hexamethyldisilazane, and 1-(trimethylsilyl)imidazole does not eliminate peak tailing. Column activity tests show that the PMP treatment also improves the peaks for 2,6-dimethyl aniline, 1-octanol, and 1-decanol implying a decrease in the column's hydrogen bonding sites with the PMP treatment. FT-IR analysis shows that exposure to PMP forms a bond to the stationary phase that deactivates the active sites responsible for organophosphonate peak tailing.