Аннотация:Dibutyl phthalate (DBP) is widely used as a plasticizer in the production of polymericmaterials to give them flexibility, strength and extensibility. However, due to its negative impacton human health, in particular reproductive functions and fetal development, the content of DBPmust be controlled in food and the environment. The present study aims to develop a sensitive, fastand simple fluorescence polarization immunoassay (FPIA) using monoclonal antibodies derivedagainst DBP (MAb-DBP) for its detection in open waters. New conjugates of DBP with variousfluorescein derivatives were obtained and characterized: 5-aminomethylfluorescein (AMF) anddichlorotriazinylaminofluorescein (DTAF). The advantages of using the DBP-AMF conjugate in theFPIA method are shown, the kinetics of binding of this chemical with antibodies are studied, theanalysis is optimized, and the concentration of monoclonal antibodies is selected for sensitivityanalysis—16 nM. The calibration dependence of the fluorescence polarization signal for the detectionof DBP was obtained. The observed IC50 (DBP concentration at which a 50% decrease in thefluorescence polarization signal occurs, 40 ng/mL) and the limit of detection (LOD, 7.5 ng/mL) valueswere improved by a factor of 45 over the previously described FPIA using polyclonal antibodies. Thistechnique was tested by the recovery method, and the high percentage of DBP discovery in waterranged from 85 to 110%. Using the developed method, real water samples from Lake Onega weretested, and a good correlation was shown between the results of the determination of DBP by theFPIA method and GC-MS. Thus, the FPIA method developed in this work can be used to determineDBP in open-water reservoirs.