Spectrofluorimetric Study of Supramolecular Inclusion between Rodenticide Brodifacoum and β-Cyclodextrin and Application

The supramolecular interaction between p-cyclodextrin and brodifacoum, an anticoagulant rodenticide of the second generation, was studied by spectroscopy. The results showed that brodifacoum and beta-cyclodextrin could form an inclusion complex with an association constant of 1. 048 X 10(4) L . mol(-1) and a 1 : 1 stoichiometry based on Benesi-Hildebrand equation. The inclusion mechanism was proposed to explain the inclusion mode. It was indicated that the hydrophobic group of brodifacoum molecule, biphenyl, entered into the cavity of p-cyclodextrin. At the same time, it was also observed the significant enhancement of fluorescence of brodifacoum after forming inclusion complex. According to the fluorescence enhancement phenomenon, a spectrofluorimetric method of detecting brodifacoum in aqueous media was established with the linear range of 8. 0 X 10(-8)-4. 0 X 10(-6) mol . L-1 and the correlation coefficient of 0. 999 4. The detection limit of the method was 8. 8 X 10(-9) mol . L-1 The proposed method was successfully applied to determine the trace amount of brodifacoum in environment water and the recovery was in the range of 87. 3% to 103. 9%.