Institute of Chemistry, University of Campinas, P.O. Box 6154, 13083-970, Campinas, SP, Brazil.
J Chromatogr A. 2012 Oct 19;1260:81-7. doi: 10.1016/j.chroma.2012.08.048. Epub 2012 Aug 23.
Endcapped stationary phases were prepared after thermal immobilization of poly(methyloctadecylsiloxane) (PMODS) onto zirconized and titanized silica supports. These new stationary phases have lower densities of residual hydroxyl groups, according to infrared spectroscopy and 29Si CP-MAS NMR and as shown by the symmetrical peaks of basic compounds from the Tanaka, Engelhardt and SRM 870 test mixtures. Stability tests for the endcapped stationary phases, measured using severe alkaline conditions (70:30 (v/v) methanol:0.05 mol/L K2CO3/KHCO3, pH 10, 50 °C), revealed that the stabilities of these phases are greater than the stabilities of similar nonendcapped phases. The stationary phases showed good performance for the separation of basic pharmaceuticals.
经热固载法将聚甲基辛基硅氧烷（PMODS）固定在锆化和钛化硅胶载体上，制备了端封固定相。根据红外光谱和 29Si CP-MAS NMR 以及 Tanaka、Engelhardt 和 SRM 870 测试混合物中碱性化合物的对称峰表明，这些新型固定相的残留羟基密度更低。使用苛刻的碱性条件（70:30（v/v）甲醇：0.05mol/L K2CO3/KHCO3，pH 10，50°C）对端封固定相进行稳定性测试，结果表明这些固定相的稳定性大于类似的非端封固定相的稳定性。这些固定相在碱性药物的分离中表现出良好的性能。
