Immunoaffinity column clean-up for the determination of imazalil in citrus fruits Original Research Article

We have developed a new clean-up method with immunoaffinity purification using anti-imazalil monoclonal antibody (MAB). Immunoaffinity purification of residual imazalil in citrus fruits could lead to a more effective and specific clean-up technique for isolation and concentration. A column containing anti-imazalil MAB immobilized to CNBr-activated agarose gel was prepared, and utilized for immunoaffinity chromatographic (IAC) clean-up for imazalil in citrus fruit samples such as lemons, oranges, and grapefruits. The prepared IAC clean-up column had sufficient total column capacity, and could be reusable at least thirty times per one IAC clean-up column. The newly developed method was able to eliminate co-exiting sample matrices originated from citrus fruits more successfully than the conventional clean-up method in respect of the simplicity and the rapidity of the procedure. The recoveries from citrus fruit samples fortified with imazalil at 0.05, 0.5, and 5 ppm were in the range of 85.2 to 98.8% with coefficients of variation (CV) of 1.8–6.6%. It took only about 1 h to complete the whole procedure from extraction to HPLC analysis. Furthermore, a clean analysis was achieved by using the proposed IAC clean-up method. The applicability of this method was demonstrated by measuring the residual imazalil in commercial citrus fruits. The study suggested that the IAC clean-up column for imazalil will be able to overcome some difficulties the conventional analyses for pesticides residue in foods were not able to.