Synthesis of a Carboxyl-functionalized Magnetic Carbon Nanotube and Its Extraction for Clenbuterol in Pork Samples

KeyWord:clenbuterol  ractopamine  oxidation£­precipitation  carbon nanotube  magnetic solid extraction  ultra-high performance liquid chromatography

Abstract:

      A carboxyl-functionalized magnetic carbon nanotube of Fe3O4£­Cys@CNT was synthesized by a facile oxidation£­precipitation method under the ultrasonic-assisted condition£¬with Fe2+£¬oxygen and L-cysteine£¨L-Cys£© as ferrous precursor£¬oxidant and protectant£¬respectively£®The obtained magnetic carbon nanotube was characterized by Fourier transform£­infrared spectroscopy£¨FT£­IR£©£¬X-ray diffractometry£¨XRD£© and transmission electron microscopy£¨TEM£©£®The results showed that Fe3O4£­Cys NPs with a diameter of 20 nm was homogeneously distributed on the surface of CNT£®Based on this£¬an ultra-high performance liquid chromatography with magnetic solid-phase extraction£¨MSPE/UPLC£© was established for the analysis of clenbuterol£¨CLB£© and ractopamine£¨RAC£© in pork samples via using Fe3O4£­Cys@CNT as the adsorbent£®Under the optimal extraction conditions£¬there were good linear relationships for CLB and RAC in the concentration range of 0.5£­100 ¦Ìg/L£¬with correlation coefficients£¨r£© not less than 0.997 4 and the limits of detection£¨LOD£© of 0.15 ¦Ìg/L£®The recoveries for CLB and RAC ranged from 95.1% to 112%£¬with relative standard deviations£¨RSD£© less than 11%£®The extraction efficiency of Fe3O4£­Cys@CNT reduced less than 3% after it was used repeatedly for 4 times£¬indicating that the adsorbent was recyclable£®With the advantages of simple preparation£¬short synthesis time and environmental protection£¬the Fe3O4£­Cys@CNT prepared is a promising MSPE adsorbent£¬which could separate and enrich CLB and RAC in complex matrix rapidly£®The preparation method of the new adsorbent and the established method provide new ideas for the detection of clenbuterol in complex food and biological samples£®