Pentamidine-imprinted polymers

Sellergren [58] has used the same type of binding partners in a reverse manner, preparing pentamidine imprinted polymers for solid-phase extraction with methacrylic acid as functional monomer. Addition of an excess of acid to an isopropa-nolic, template containing polymerization mixture led to formation of a precipitate which was dissolved by adding water. 

Fig. 12.5. Electron micrographs of dispersion/precipitation polymers imprinted with pentamidine in isopropanol-water. Magnification in (A) 2000 x and in (B) 10,000 x. (From [26])...

The first MISPE protocol reported in the literature [18] involved the use of an imprinted dispersion polymer in a column format, for the selective enrichment of pentamidine (1) in urine. In this case the high selectivity of the polymer allowed the analyte to be detected directly in the eluate without the need for any further chromatographic separation (entry A in Tables 15.1 and 15.2). In view of the high selectivity of MIPs, this is a viable approach that brings the benefits of shorter analysis times and simpler instrumentation. In most cases, however, MISPE has been used prior to a chromatographic separation step. The MIP has been applied in a batch-wise extraction [23] or in columns or cartridges [20-22,24-26,33]. 

The first reported preparation of capillary columns containing MIPs utilised a thermally initiated dispersion polymerisation procedure [58], The functional monomer MAA and the cross-linking monomer EDM A were used. Agglomerates of micrometre-sized globular polymer particles were claimed to be prepared in situ in the capillary. Molecular imprinting of L-phenylalanine anilide, pentamidine and benzamidine was undertaken. A pH-dependent retardation of pentamidine over benzamidine in the pentamidine capillary was observed, while the opposite. 

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