Synthetic approaches to parabens molecularly imprinted polymers and their applications to the solid-phase extraction of river water samples

Synthesis, characterization, and use of 2 distinct molecularly-imprinted polymers (MIP) prepd. using p-hydroxybenzoic acid (paraben) esters as templates are reported.: one MIP was synthesized by pptn. polymn. using a semi-covalent molecularly imprinting strategy with Me paraben as the template/target (MIP 1); the second MIP was prepd. in monolithic form through a conventional non-covalent mol. imprinting strategy, with Bu paraben as the template (MIP 2). One MIP was synthesized by pptn. polymn. using a semi-covalent molecularly imprinting strategy with Me paraben as the template/target (MIP 1); the second MIP was synthesized in monolithic form using a conventional, non-covalent mol. imprinting strategy with Bu paraben as the template (MIP 2). MIP 1 recognized Me paraben, showed cross-selectivity for other studied paraben analytes, and a higher affinity toward these compds. than a non-imprinted control polymer. Similarly, MIP 2 demonstrated a higher affinity toward paraben analytes than a non-imprinted control polymer. For anal. of environmental water, a solid phase extn. (SPE) protocol was developed using MIP 2 as sorbent; results were compared to SPE using a com. sorbent (Oasis HLB). With MIP 2 as sorbent and Bu paraben as target, when percolating 500 mL of river water spiked at 1 μg/L through the SPE cartridge, and using 1 mL of isopropanol as cleaning solvent, a higher Bu 4-hydroxybenzoate (Bu paraben) recovery and a cleaner chromatogram where achieved when using the MIP vs. the com. sorbent.