Molecularly imprinted polymers for selective extraction of analytes from biological samples.
Résumé
The analysis of interest compounds from biological samples requires a procedure of pretreatment in order to preconcentrate the analytes and clean-up the matrix. Despite its attractive features, classical sorbents used in SPE retain analytes by non selective hydrophobic interactions that lead to a partial coextraction of interfering substances. So, sorbents displaying more selective interactions are powerful tools for the development of sensitive and more reliable methods. Immunoaffinity supports can be used to obtain a selective extraction. They are based on the immobilization of specific antibodies developed against the target analyte (Immunosorbent). Nevertheless, the cost and the time required to produce antibodies lead to the development of a new polymeric material: the Molecularly Imprinted Polymers (MIP). These supports possess molecular recognition sites designed for the analyte of interest. With performances similar to immunosorbents in terms of selectivity, MIPs present a better thermic and chemical stability and the cost of synthesis is also reduced. Like immunosorbents, their retention mechanism is based on molecular recognition. In most cases, the developed interactions during the extraction are non covalent like - hydrogen bondings, π π − or electrostatic interactions. The most common approach to the synthesis is the bulk polymerisation to obtain a monolithic polymer. MIPs for SPE can be conditioned in cartridges or directly integrated in the analytical system. Many applications have already highlighted the high potential of MIPs for the selective extraction of target compounds from biological samples.