Stability of silica-based, endcapped columns with pH 7 and 11 mobile phases for reversed-phase high-performance liquid chromatography
Stability of silica-based, endcapped columns with pH 7 and 11 mobile phases for reversed-phase high-performance liquid chromatography
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DOI：
10.1016/s0021-9673(96)00945-4
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发表时间：
1997-02-21
影响因子：
4.1
通讯作者：
Claessens, HA
中科院分区：
文献类型：
--
作者：
Kirkland, JJ;Henderson, JW;Claessens, HA
这项研究的目的是确定在中等和较高pH环境中使用硅胶基端盖键合相柱开发坚固的高效液相色谱方法的实际条件和限制。在这个pH范围内，键合相的降解主要是硅胶载体溶解的结果；在中等和更高的pH下，共价键合的硅烷配体从硅胶载体上水解的速度非常慢。根据化学测量和可比层析研究确定的硅胶载体溶解速度，我们现在发现，与未封端的柱相比，封端烷基键合固定相在pH 7时延长了柱的寿命。正如之前对非封端填料所确定的那样，我们还发现二氧化硅载体的类型决定了键合相填料的稳定性，通过溶胶-凝胶法制备的二氧化硅比通过硅酸盐-凝胶(干凝胶)工艺制备的载体更耐溶解。此外，封端方式对柱子稳定性有明显影响，双端封端方法明显优于单端封端方法。在高度侵略性的pH 7加速寿命试验中，发现几个端盖商用键合相C-8柱的降解率非常不同。通过在流动相中使用磷酸盐以外的缓冲液，以及通过排除较高的柱温，可以提高柱在pH 7-11范围内的稳定性。某些硅基端盖键合相柱在低于或等于40℃的温度下与有机缓冲液一起使用时，可用于开发至少pH为11的坚固方法。
The goal of this study was to define practical conditions and limitations of using silica-based, endcapped bonded-phase columns in intermediate and higher pH environments for developing rugged HPLC methods. Bonded-phase degradation in this pH range is a result mainly of silica support dissolution; covalently-bound silane ligands are hydrolyzed very slowly if at all from silica supports at intermediate and higher pH. Based on rates of silica support dissolution determined by chemical measurements and comparable chromatographic studies, we now find that endcapping alkyl-bonded stationary phases increases column longevity at pH 7, compared to non-endcapped columns. As previously determined for non-endcapped packings, we also find that the type of silica support determines the stability of bonded-phase packings, Silicas made by the sol-gel process are more resistant to dissolution than supports made by a silicate-gel (xerogel) process. In addition, endcapping methods apparently affect column stability, with double-endcapping methods apparently superior to single-endcapping approaches. Degradation rates for several endcapped commercial bonded-phase C-8 columns were found to be quite variable in highly aggressive pH 7 accelerated-lifetime tests. Column stability in the pH 7-11 range is enhanced by using buffers other than phosphate in the mobile phase, and by excluding higher column temperatures. Certain silica-based endcapped bonded-phase columns can be used for developing rugged methods to at least pH 11 when used with organic buffers at less than or equal to 40 degrees C.