Magnetic porous carbon-based solid-phase extraction of carbamates prior to HPLC analysis

Magnetic Fe3O4-doped porous carbon (MPC) was synthesized by using a metal-organic framework as a sacrificial template and iron salts as magnetic precursors. The textural properties of the MPC were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibration sample magnetometry, and nitrogen absorption-desorption isotherms. The MPC possesses a high specific surface and is strongly magnetic. It was employed as an adsorbent for magnetic solid-phase extraction of four carbamates. The main parameters that affect extraction efficiency were investigated. The carbamates were analyzed by high performance liquid chromatography with ultraviolet detection at 208 nm. Under optimum conditions, good linearity was achieved for all analytes in the 1-100 ng g(-1) concentration range, with correlation coefficients of > 0.9992. The limits of detection (at an S/N ratio of 3) are between 0.1 and 0.2 ng g(-1), and the recoveries of spiked samples ranged from 89.3 to 109.7 %.