Rapid Colorimetric Determination Of Micro Amount Melamine In Dairy Products

Super-paramagnetic nano-material has attracted much attention because they have broad and far-reaching applications in biological, medicinal, clinical diagnosis. At the same time, magnetic nano-materials, particularly Fe3O4 magnetic nanoparticles, have been widely used in manufacturing, chemical, catalytic reagent due to their special physical and chemical properties. So the synthesis, surface modification, characterization and many other disciplines in the practical application of magnetic nano-materials has been becoming an emerging interdisciplinary field in recent yearsAmong the many methods for preparing Fe3O4 magnetic nanoparticles, co-precipitation is the simplest one, which could prepare Fe3O4 magnetic nanoparticles with uniform size and good dispersivity. The Fe3O4 magnetic nanoparticles which obtained by a co-precipitation method also exhibited an intrinsic activity as peroxidase, which could be used to detect hydrogen peroxide. Because of this special characteristic, we established a new method for the determination of trace amount of melamine in dairy products by measuring the wastage of H2O2. This dissertation introduces the derivative works based on this research work:Chapte 1. The basic knowledge of nanotechnology, nano-materials, the special property and applications of nano-materials, the character of nano-materials, the common preparation methods and the applications in different sides in scientific research are introduced.Chapte 2. Fe3O4 magnetic nanoparticles which could be used as the mimetic enzyme of peroxidase were preparec by co-precipitation method. The characterization results showed that the size of Fe3O4 magnetic nanoparticles were uniform and dispersed. As the mimetic enzyme of peroxidase, the prepared Fe3O4 magnetic nanoparticles show the good catalytic activity. The Fe3O4 magnetic nanoparticlesits could be used to detect H2O2 and melamine. Chapte 3. A new method based on the Fe3O4 MNPs-H2O2-ABTS detection system for determining melamine in dairy products by using the 721-A spectrophotometry is established. The results show that the detection limit is lower than the safety limit of China, and the recoveries are good. The final results could be obtained by eye.