Novel monolithic poly(phenyl acrylate-co-1,4-phenylene diacrylate) capillary columns for biopolymer chromatography

Monolithic capillary columns were prepared by thermally initiated free radical polymerisation of phenyl acrylate (PA) and 1,4-phenylene diacrylate (PDA) in the confines of 200 microm I.D. fused silica capillaries. Polymerisation was performed in the presence of 2-propanol and tetrahydrofuran (THF) as inert diluents (porogens), using alpha,alpha'-azoisobutyronitrile (AIBN) as initiator. Morphology and porosity of the resulting monoliths were comprehensively studied by scanning electron microscopy (SEM), mercury intrusion porosimetry and inverse size-exclusion chromatography (ISEC). The novel poly(phenyl acrylate-co-1,4-phenylene diacrylate) (PA/PDA) monoliths showed high mechanical stability and were successfully applied to the separation of proteins and oligodeoxynucleotides, employing reversed-phase (RP) and ion-pair reversed-phase (IP-RP) conditions, respectively. Maximum loading capacities for cytochrome c and d(pT)(16) were evaluated and found to be in the region of 200 fmol. Batch-to-batch reproducibility was determined for three independently prepared PA/PDA monolithic capillary columns. Relative standard deviations (RSDs) of retention time (t(R)) of 0.7-1.6% for proteins and 0.2-2.5% for d(pT)(12-18) proved high reproducibility of the PA/PDA supports.