Miroslav Petro

Immobilization of trypsin onto Molded macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate) rods and use of the conjugates as bioreactors and for affinity chromatography

Trypsin immobilization onto continuous “molded” rods of porous poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) and some applications of the conjugate have been studied. The rods polymerized within a tubular mold (chromatographic column), were treated in situ with ethylenediamine, activated with glutaraldehyde and finally modified with trypsin. The performance of the trypsin‐modified rods was evaluated and compared to that of poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) beads, modified with the same enzyme. Overall the enzyme‐modified rods performed substantially better than the corresponding beads. In particular, the performance of the molded supports as enzymatic reactors or as chromatographic media benefits greatly from the enhanced mass transfer that is characteristic of the molded rod at high flow rates.

Chiral electrochromatography with a ‘moulded’ rigid monolithic capillary column

Several monolithic chiral stationary phases for reversed-phase electrochromatography have been prepared within the confines of untreated fused silica capillaries by the direct copolymerization of the chiral monomer 2-hydroxyethyl methacrylate (N-L-valine-3,5- dimethylanilide) carbamate with ethylene dimethacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and butyl or glycidyl methacrylate in the presence of a porogenic solvent. The hydrophilicity of the stationary phase, which may be enhanced further by the hydrolysis of the epoxide functionalities of the glycidyl methacrylate moieties within the monolith, was found to have a pronounced effect on the enantioseparation. Using the most hydrophilic monolithic capillary column and optimized elution conditions, a separation of N-(3,5-dinitrobenzoyl)leucine diallylamide enantiomers with an efficiency of 61000 plates m–1 and a resolution of 2.0 was achieved.

Molded continuous poly(styrene-co-divinylbenzene) rod as a separation medium for the very fast separation of polymers Comparison of the chromatographic properties of the monolithic rod with columns packed with porous and non-porous beads in high-performance liquid chromatography of polystyrenes

Gradient elution separations of polystyrene standards in a monolithic molded 50 x 8 mm I.D. poly(styrene-co-divinylbenzene) rod column and in 50 x 8 mm I.D. and 30 x 4.1 mm I.D. columns packed with porous and non-porous poly(styrene-co-divinylbenzene) beads has been carried out. All of these separation media differ in shape and porosity. Excellent separations of eight polystyrene standards were achieved with both the molded monolithic rod and porous beads at moderate flow-rates. However, the monolithic medium proved to be superior for high-speed separations using very steep gradients at a flow-rate of 20 ml/min. Three polystyrene standards were separated in the rod column within 4 s. The separation in the column packed with non-porous beads was poor at flow-rates of 2-8 ml/min, while higher flow-rates led to an unacceptably high back pressure.

Chromatography of functional polymers: A new approach to the characterization of reactive polymers obtained by chemical modification

High-performance liquid chromatography ( HPLC ) has been used to complement size-exclusion (gel permeation) chromatography ( SEC ) for the characterization of functional polymers. Whereas SEC is unable to detect compositional changes, HPLC in an appropriate interacting medium can provide detailed information on compositional changes occurring during chemical modification of a polymer. The method has been demonstrated using a normal-phase column consisting of porous monodisperse 10 μm poly( 2,3-dihydroxypropyl methacrylate-co-ethylene dimethacrylate) beads that have a homogeneous coverage of aliphatic hydroxyl groups for the analysis of brominated poly( isobutylene-co-4-methylstyrene ). Differences of well below 1 mol % of bromomethylstyrene units are easily detected and quantified.