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

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 5ppm were in the range of 85.2 to 98.8% with coefficients of variation (CV) of 1.8-6.6%. It took only about 1h 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.