Agglomerated silica monolithic column for hydrophilic interaction LC.

Hydrophilic interaction LC (HILIC) has gained wide acceptance in recent years due to its ability to retain and separate polar compounds such as pharmaceuticals. Most commercial HILIC phases are particle based, which limit the speed with which HILIC separations can be performed. Herein, agglomerated silica monolithic columns are prepared by electrostatically attaching polyionic latex particles onto a silica monolith by simply flushing a suspension of the ionic latex through a silica monolith. Such phases retain the high efficiency and permeability of the native silica monolith, while the agglomerated phase is easy to introduce and provides excellent mass transfer. High %ACN in the mobile phase dramatically increases the efficiency and retention, consistent with HILIC behavior. Test analytes such as benzoates, nucleotides and amino acids are separated with plate heights of 25-110 microm. The high permeability of monoliths allows HILIC separations to be performed with baseline resolution in less than 15 s. Electrostatic repulsion-hydrophilic liquid interaction chromatographic retention behavior of the latex-coated monoliths is verified using amino acids as test analytes.