Improved molecularly imprinted polymer grafted to porous polyethylene frits for the solid-phase extraction of thiabendazole from citrus sample extracts

Abstract In this paper, the improvement over a novel format for selective solid-phase extraction based on a molecularly imprinted polymer (MIP) is described. A small amount of MIP has been synthesized within the superficial pores of commercial polyethylene (PE) frits and attached to its surface using benzophenone (BP), a photo-initiator capable to start the polymerization from the surface of the support material. Key properties affecting the obtainment of a proper polymeric layer, such as polymerization time and kind of cross-linker were optimized. Prepared composite material was applied to the SPE of TBZ in real samples extracts, showing an impressive clean-up ability. Calibrations showed good linearity in the concentration range of 0.05–5.00 μg g-1, referred to the original solid sample, and the regression coefficients obtained were greater than 0.998. The calculated detection limit was 0.01 μg g-1, low enough to satisfactory analysis of TBZ in real samples. Mean recoveries were about 70 % at different concentration levels with RSDs always ranged below 15% in all the cases.