Functionalized polysilsesquioxane film fluorescent sensors for sensitive detection of polychlorinated biphenyls

Development of a rapid, highly sensitive and simple technique for screening polychlorinated biphenyls (PCBs) remains a challenge. In the present study, a novel fluorescent film chemosensor for PCBs based on fluorescence quenching was designed and synthesized. The fluorescent chemosensor is a hybrid organic–inorganic functionalized polysilsesquioxane film that is prepared from γ-(N,N-diphenylcarbamino)propyltriethoxysilane by sol–gel polymerization. The prepared fluorescent polysilsesquioxane film with diphenylamine as a fluorescent probe is sensitive to aqueous solutions of PCBs, including 2-chlorobiphenyl (PCB1), 2,2′-Dichlorobiphenyl (PCB4), 2,2′,5-trichlorobiphenyl (PCB18), 3,3′,4,4′-tetrachlorobiphenyl (PCB77) and 2,2′,4,5,5′-pentachlorobiphenyl (PCB101). PCBs efficiently quench the fluorescence of the chemosensor via a photo-induced electron transfer (PET) process. The fluorescence emission intensity of the polysilsesquioxane film sensor decreased steadily with a corresponding increase in PCBs. The detection limit of PCB77 was found to be 8.03 × 10−7 M. The obtained results show that this fluorescent sensor has good thermal stability, high sensitivity and satisfactory reversibility in PCBs sensing.