Semi-micro-monolithic columns using macroporous silica rods with improved performance.

Monolithic silica columns in semi-micro-format have been synthesized using poly(acrylic acid) as a phase-separation inducer via a sol-gel route. The absence of a thick skin layer accompanied by deformation of the micrometer-sized gelling skeletons on the outermost part of the macroporous silica rod contributed to improve the efficiency of monolithic silica columns as thick as 2.4 mm in diameter. The kinetic plot analysis revealed that monolithic silica columns with macropore diameter of 1 microm and skeleton thickness of 1 microm with decreased macroporosity behave similarly to columns packed with 3 microm particles with slightly lower back pressure.