Molecularly Imprinted Matrices for Electrochromatography

Abstract: This thesis deals with the combination of electrochromatography and molecular imprinting technology. Electrochromatography is characterised by high separation efficiency, simple instrumentation, and minute consumption of sample. As a novel approach to obtain unique selectivity in capillary electrochromatographic systems molecularly imprinted matrices were used. Molecular imprinting technology represents a means to prepare sorbents with affinity for a predetermined ligand by employing a molecular template during the sorbent preparation. The merge of the two techniques include the adaptation of molecular imprinting technology to the capillary dimensions. Three conceptually different adaptation formats were developed and evaluated as stationary or pseudostationary phases in capillary electrochromatography. These were superporous monoliths, microparticles, and coatings. The monoliths was prepared by in situ polymerisation and made superporous to facilitate simple practical usage. The superpores were prepared by a polymerisation interruption method or by the use of a porogenic agent compatible with the molecular imprinting process. Microparticles were prepared by a precipitation polymerisation process and used as a pseudostationary phase by a partial filling method. The coatings were synthesised in situ and limited to the vicinity of the capillary surface by means of a surface coupled radical initiator. Electrochromatographic separation of enantiomers was achieved using all formats of molecularly imprinted polymer. Generally, electrolytes of high organic solvent content in mixture with low pH buffer were found to be suitable. Approaches to improve performance involved different types of electrolyte additives, electrochromatographic parameters, and polymer composition.