| In this paper,2-acrylamidoquinoline was used as both fluorescent reporter and functional monomer to synthesize melamine-imprinted nanoparticles in constructing the chemosensor for converting the binding events into physically detectable signals by monitoring fluorescence spectra. The procedures are as followed, first, the monodispersed spherical silica nanoparticles (about 250 nm) were prepared by hydrolysis of TEOS. Then, the nanoparticles were further modified by using 3-(methacryloxy) propyltrimethoxysilane. Finally, the molecularly imprinted polymers were coated at the surface of silica nanoparticles by the copolymerization of methacrylic acid,2-acrylamidoquinoline and ethylene glycol dimethacrylate in the presence of melamine (MA). The obtained imprinted materials were evaluated by transmission electron microscope and rebinding experiments, exhibiting well-controlled shell thickness (-6 nm) and high binding capacity (70.20 umol g-1) to MA. Moreover, the rebinding amount of imprinted nanoparticles to MA was about 4.5 folds that of nonimprinted nanoparticles. When the MA-imprinted nanoparticles were used as dispersive solid-phase extraction materials and chemosensors, they could enrich and determine trace MA from dairy products by mechanism of fluorescence enhancement. The recoveries (RSDs) of MA determined by fluorescence spectrophotometer (FS) were 94.8%(0.7%),98.5%(2.5%) and 102.1%(2.2%) in the spiked milk, yogurt and ice-cream samples, respectively. Therefore, the method will provide new opportunities for enrichment and detection of trace illegitimate additives (which have nonfluorescent property) from food. |
