Immunoaffinity column clean-up for the determination of imazalil in citrusfruits

We have developed a new dean-up method with immunoaffinity purification usi ng anti-imazalil monoclonal antibody (MAB). Immunoaffinity purification of residual imazalil in citrus fruits could lead to a more effective and speci fic 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 prep ared 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 deve loped method was able to eliminate co-exiting sample matrices originated fr om citrus fruits more successfully than the conventional clean-up method in respect of the simplicity and the rapidity of the procedure. The recoverie s 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 extra ction to HPLC analysis. Furthermore, a clean analysis was achieved by using the proposed IAC clean-up method. The applicability of this method was dem onstrated by measuring the residual imazalil in commercial citrus fruits. T he study suggested that the IAC clean-up column for imazalil will be able t o overcome some difficulties the conventional analyses for pesticides resid ue in foods were not able to. (C) 2001 Elsevier Science B.V. All rights res erved.