A common drawback of silica-based polar stationary phase is obvious bleeding, probably resulting from silica dissolution in water attracted onto silica gel. Recently we have reported a polyvinyl alcohol (PVA) encapsulated silica gel stationary phase for hydrophilic interaction liquid chromatography (HILIC), which demonstrated good chromatographic performance. Although PVA coating outside could shield SiO₂ inside from erosion by aqueous solution to a certain degree, obvious bleeding of such phase was still observed. To eliminate or reduce the bleeding level of the phase, fabricating multi-layers of PVA coating crosslinked with glutaraldehyde onto silica gel is performed (PVA-GA-Sil). ∼20-fold decrease of the bleeding for PVA-GA-Sil can be achieved relative to bare silica gel, which is much lower than (or comparable to) commercial HILIC phases. PVA-GA-Sil also showed chromatographic performance and demonstrated superiority to commercial columns operated at gradient mode.

硅胶基极性固定相的一个常见缺点是明显的渗色，可能是由于二氧化硅溶解在被硅胶吸引的水中而引起的。最近，我们已经报道了用于亲水性相互作用液相色谱（HILIC）的聚乙烯醇（PVA）封装的硅胶固定相，该色谱相具有良好的色谱性能。尽管外面的PVA涂层可以屏蔽SiO ₂水溶液被侵蚀到一定程度后，仍观察到明显的渗出。为了消除或减少相的渗出程度，需要进行将戊二醛交联到硅胶上的多层PVA涂层的制备（PVA-GA-Sil）。相对于裸露的硅胶，PVA-GA-Sil的渗漏可减少约20倍，这比市售HILIC相要低得多（或可比）。PVA-GA-Sil还表现出色谱性能，并且比在梯度模式下运行的商业色谱柱优越。