[Synthesis and chromatographic evaluation of sulfobetaine-based capillary zwitterionic hydrophilic monolithic column...

Sulfobetaine-based capillary zwitterionic hydrophilic monolithic columns were synthesized with a novel binary porogenic agent of polyethylene glycol (PEG)/methanol. The polymer was prepared with (3-(metharyloylamino) propyl) dimethyl (3-sulfopropyl) ammonium hydroxide inner salt (SPP) as monomer, pentaerythritol triacrylate (PETA) as crosslinker, and azobisisobutyronitrile (AIBN) as initiator. In order to optimize the properties, the contents of the polymerization mixture were investigated. The optimum preparation conditions were as follows: the mass ratio of monomer and porogenator = 1:2.5; the mass ratio of SPP and PETA = 1:1 in the monomer; the mass ratio of PEG and methanol = 2:1 in the binary porogenic agent; the content of the initiator (AIBN) = 0.1% (m/m). With the binary porogenic agent of PEG/ methanol addition, good mechanical stability, homogeneous column bed, good permeability and narrow pore size distribution were obtained. In the capillary liquid chromatography mode, the hydrophilic monolith provided column efficiency up to 2.4 x 10(5) plates/m which was much higher than that fabricated by traditional method without PEG/methanol. The columns were used in capillary liquid chromatography and pressurized capillary electrochromatography for the separation of a mixture of phenols, nucleosides and so on.