Fluorescence polarization immunoassay based on a new monoclonal antibody for the detection of the Diisobutyl phthalate in Yoghurt

To develop a sensitive fluorescence polarization immunoassay (FPIA) for detecting Diisobutyl phthalate (DIBP) in Yoghurt. Five tracers with different lengths of bridge between the hapten molecule and fluorescein isothiocyanate (FITC), fluoresceinthiocarbamyl ethylenediamine (EDF), fluoresceinthiocarbamyl hexylenediamine (HDF), were synthesized and their respective binding responses with anti-DIBP-specific antibody were evaluated. The physicochemical parameters were optimised for the FPIA. The FITC-labelled DIBP conjugate (DIBP-FITC) was found to be the optimal tracer for FPIA of Diisobutyl phthalate. The detection limit of DIBP, IC50 value and the working range were 0.82, 9.32 and 1.16–74.97 ng/mL, respectively; and the reaction time was only 5min. The average recovery from spiked Yoghurt samples was 77.80–115.60% which showed good reproducibility for FPIA. Thus, the developed FPIA method exhibited the potential for the rapid and accurate determination of DIBP in agricultural and environmental samples.