Preparation of molecularly imprinted hybrid monoliths for the selective detection of fluoroquinolones in infant formula powders.

A novel molecularly imprinted inorganic-organic hybrid monolith (MIP hybrid monolith) was fabricated through a facile single-step polymerization strategy with levofloxacin (LEV) as the template, 3-aminopropyltriethoxysilane-methacrylic acid as the hybrid functional monomer and ethylene glycol dimethacrylate as the crosslinker in a mixed porogen of methanol, toluene and dodecanol. The optimized LEV-MIP hybrid monolith was characterized using scanning electron microscopy and fourier transform-infrared spectroscopy. Uniform monolithic matrix with large through-pores in the network skeleton of LEV-MIP hybrid monolith was observed. The influence of polymerization conditions on the specific recognition behavior of the resulting monolith was systematically investigated. The LEV-MIP hybrid monolith exhibited much better adsorption (3.62 times) and selectivity towards LEV in comparison with non-imprinted hybrid monolith. Furthermore, the LEV-MIP hybrid monolith based solid-phase extraction combining with liquid chromatography-mass spectrometry was applied for the selective determination of fluoroquinolones (FQs) in infant formula powder. The average recoveries of six FQs in milk powders spiked at 20, 50 and 100 μg kg were in the range of 82.91-102.00% with the precision of 1.04-7.39%. The limit of detection and limit of quantitation of the proposed method were in a range of 0.19-1.24 μg kg and 0.63-4.13 μg kg, respectively.