Mesoporous molecularly imprinted polymer core@shell hybrid silica nanoparticles as adsorbent in microextraction by packed sorbent for multiresidue determination of pesticides in apple juice

摘要

In this work, we report the synthesis of a mesoporous molecularly imprinted polymer on the surface of silica nanoparticles (core@mMIP) to be applied as adsorbent in microextraction by packed sorbent (MEPS) for selective determination of pesticides in apple juice. The core@mMIP was properly characterized, showing good adhesion of the polymer to the silica core. The best extraction conditions were: 200 mu L of ultrapure water as washing solvent, 150 mu L of acetonitrile as eluent, 100 mu L of sample at pH 2.5, five draw-eject cycles and 8 mg of adsorbent. Thereby, recoveries of 96.12 +/- 1.05%, 76.88 +/- 6.18% and 76.18 +/- 5.57% were obtained for pyriproxyfen (PPX), deltamethrin (DTM) and etofenprox (ETF), respectively. After validation, the method presented linearity in the range of 0.02-10 mu g mL(-1) (r 0.99), limit of detection of 0.005 mu g mL(-1) satisfactory selectivity, and proper precision and accuracy. The method was successfully applied real samples of processed and fresh apple juice.