Application Molecularly Imprinted Solid Phase Extraction Method for Analysis and Determination of Bentazon as a Toxic Herbicide in Water

In  this  paper,  a  highly  selective  sample  cleanup  procedure  combining  molecular  imprinting  and solid phase extraction (MI-SPE) was developed for the isolation of toxic bentazon in surface water. The molecularly imprinted polymer (MIP) was prepared using bentazon as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linking monomer. The  bentazon  imprinted  polymer  was  used  as  a  selective  sorbent  for  the solid-phase extraction  of  bentazon  from  surface  water.  An  offline  MI-SPE  method  followed  by  highperformance liquid chromatography was also established. To evaluate the applicability of the MIP for separation and determination of bentazon by HPLC, general parameters for SPE including the number of  loading  solvents,  washing  solution  and  eluent, and  pH  of  the  sample  were  optimized following a step-by-step approach. The calibration curve was linear in the range of (0.05 to 0.6 µg L−1).  The  standard  deviation  of  (2.2  %)  and  detection  limit  of  the  method  (0.05  µg  L−1)  were obtained for sensor level response. It was shown that recoveries up to approximately 97.0 % from spiked surface water samples could be obtained.  It was demonstrated that the proposed MI-SPEHPLC method could be applied to the direct determination of bentazon in surface water.