Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.
Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.
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DOI：
10.1021/ac000817a
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发表时间：
2001-01
影响因子：
7.4
通讯作者：
J. Hayes;A. Malik
中科院分区：
文献类型：
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作者：
J. Hayes;A. Malik
溶胶-凝胶化学已成功用于制造用于毛细管电色谱 (OT-CEC) 的具有表面键合十八烷基硅烷 (ODS) 固定相涂层的开管柱。柱制备完成后，进行了一系列实验来研究溶胶-凝胶涂层 ODS 柱在 OT-CEC 中的性能。 N-十八烷基二甲基[3-(三甲氧基甲硅烷基)丙基]氯化铵作为溶胶-凝胶前体之一的加入对所制备色谱柱的电色谱性能起到了重要作用。该化学试剂具有色谱分析有利的键合 ODS 部分，以及三个甲氧基，可实现溶胶-凝胶反应。此外，该试剂的分子结构中存在带正电的氮原子，并提供带正电的毛细管表面，导致 CEC 操作期间柱中的反向电渗流 (EOF)。使用乙腈和甲醇作为流动相中的有机改性剂，进行了涉及此类溶胶-凝胶 ODS 涂层和未涂层毛细管内 EOF 的比较研究。对溶胶-凝胶溶液中失活剂苯基二甲基硅烷的使用进行了评估。在 CEC 中，内径为 64 cm x 25 微米的塔板效率达到每米超过 400,000 个理论塔板的效率值。溶胶-凝胶 ODS 开管柱。使用多环芳烃、苯衍生物以及芳香醛和酮的测试混合物来评估非失活和失活开管溶胶-凝胶柱的 CEC 性能。评估了流动相有机改性剂含量和 pH 对此类色谱柱中 EOF 的影响。所制备的溶胶-凝胶 ODS 柱的特点是可切换电渗流。发现大约 8.5 的 pH 值对应于所制备的溶胶-凝胶 ODS 涂层的等电点。
Sol-gel chemistry was successfully used for the fabrication of open tubular columns with surface-bonded octadecylsilane (ODS) stationary-phase coating for capillary electrochromatography (OT-CEC). Following column preparations, a series of experiments were performed to investigate the performance of the sol-gel coated ODS columns in OT-CEC. The incorporation of N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride as one of the sol-gel precursors played an important role in the electrochromatographic performance of the prepared columns. This chemical reagent possesses a chromatographically favorable, bonded ODS moiety, in conjunction with three methoxy groups allowing for sol-gel reactivity. In addition, a positively charged nitrogen atom is present in the molecular structure of this reagent and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the columns during CEC operation. Comparative studies involving the EOF within such sol-gel ODS coated and uncoated capillaries were performed using acetonitrile and methanol as the organic modifiers in the mobile phase. The use of a deactivating reagent, phenyldimethylsilane, in the sol-gel solution was evaluated. Efficiency values of over 400,000 theoretical plates per meter were achieved in CEC on a 64 cm x 25 microm i.d. sol-gel ODS open tubular column. Test mixtures of polycyclic aromatic hydrocarbons, benzene derivatives, and aromatic aldehydes and ketones were used to evaluate the CEC performances of both nondeactivated and deactivated open tubular sol-gel columns. The effects of mobile-phase organic modifier contents and pH on EOF in such columns were evaluated. The prepared sol-gel ODS columns are characterized by switchable electroosmotic flow. A pH value of approximately 8.5 was found correspond to the isoelectric point for the prepared sol-gel ODS coatings.