Faria Anizio M, Collins Kenneth E, Collins Carol H
Instituto de Química, Universidade Estadual de Campinas, Campinas, SP, Brazil.
J Chromatogr A. 2007 Jul 13;1156(1-2):51-9. doi: 10.1016/j.chroma.2006.10.032. Epub 2006 Nov 7.
The preparation of stationary phases with enhanced chemical stability in alkaline eluents has been the principal objective of many chromatographers. New and improved silica substrates and advanced chemical modification methods are among the possibilities being investigated to reach this objective. The present work has evaluated these two possibilities for new stationary phases. First, the silica surface was modified by reaction with zirconium tetrabutoxide to produce zirconized silica particles having about 21% (w/w) of zirconium. Then poly(methyltetradecylsiloxane) (PMTDS) was immobilized onto this surface using different doses (50-120 kGy) of gamma radiation. These new phases were characterized using elemental analysis and infrared and solid-state (29)Si-nuclear magnetic resonance (NMR) spectroscopies. These new stationary phases presented column efficiencies of about 68,000 plates m(-1), symmetric peaks for apolar compounds and retention factors that depend on the irradiation dose and show improved stability in high pH mobile phases. The separation of several pharmaceuticals at pH 11 is presented.
制备在碱性洗脱液中具有更高化学稳定性的固定相一直是许多色谱工作者的主要目标。为实现这一目标，正在研究的可能性包括新型和改进的硅胶基质以及先进的化学改性方法。本研究评估了新型固定相的这两种可能性。首先，通过与四丁氧基锆反应对硅胶表面进行改性，以制备含有约21%（w/w）锆的锆化硅胶颗粒。然后，使用不同剂量（50 - 120 kGy）的γ辐射将聚（甲基十四烷基硅氧烷）（PMTDS）固定在该表面上。使用元素分析、红外光谱和固态（29）Si - 核磁共振（NMR）光谱对这些新相进行了表征。这些新型固定相的柱效约为68,000理论塔板数/米（-1），对非极性化合物呈现对称峰，保留因子取决于辐照剂量，并且在高pH值流动相中显示出更高的稳定性。展示了在pH 11条件下几种药物的分离情况。
