Surface molecular imprinted polymers based on Mn-doped ZnS quantum dots by atom transfer radical polymerization for a room-temperature phosphorescence probe of bifenthrin

Abstract

Based on the room-temperature phosphorescence (RTP) peculiarity of Mn-doped ZnS quantum dots (QDs), a bifenthrin sensor was fabricated by coupling molecular imprinted polymers (MIPs) on the surface of silane modified QDs via atom transfer radical polymerization (ATRP). The stepwise synthesis was realized with ZnS QDs-NH₂-Br as the initiator, methacrylic acid (MAA) as the functional monomer, divinylbenzene (DVB) as the cross-linker, CuBr as the catalyst and 2,2′-bipyridine as the complexant. The smart RTP probe for bifenthrin was gained by surface molecular imprinting technology (SMIT) that can not only produce the stable RTP intensity of Mn-doped ZnS QDs, but can also enable more efficient recognition of the target molecule. The results presented show that the detection limit of the probe was 16.7 μg L⁻¹. The RTP stability, selectivity and sensitivity of the bifenthrin sensor were evaluated by using a spectrophotometer. The high sensitivity was due to an electron-transfer mechanism between the target and the QDs, and the particular selectivity was due to SMIT. Therefore, this novel strategy combines RTP of Mn-doped ZnS QDs with ATRP to use the best aspects of both. It offers the advantages of straightforward preparation and processing, fast response, low toxicity and optical stability, so it is very promising for the detection of bifenthrin.