Residues determination of carbofuran in vegetables based on sensitive time-resolved fluorescence immunoassay

Using direct competitive time-resolved fluorescence immunoassay (TRFIA), a rapid, highly selective and sensitive method was developed for the determination of carbofuran residues in lettuce and carrot. The method was based on a direct competitive immunoassay using europium-labelled anti-carbofuran monoclonal antibody and carbofuran-ovalbumin as coated antigen. The sensitivity, estimated as the I 50 value, was 34.54 ng/mL, with a detection limit (I 10) of 1.94 ng/mL and a practical working range between 1.33 and 341.6 ng/mL. The average recoveries of carbofuran from lettuce and carrot were 81.26–108.0% and 113.9–124.8%, respectively. Eventually, confirmation test between TRFIA and enzyme-linked immunoassay (ELISA) was performed. It confirmed that the results given by the TRFIA method were in agreement with those of the ELISA method.