Construction And Application Of Fluorescence Sensing Materials For Detection Of Heavy Metal Ions

With the rapid development of China's economy and industrial field,a large amount of heavy metal wastewater and wastes are generated,causing very serious heavy metal environmental pollution.On the one hand,it destroys the beautiful environment of our lives,on the other hand,it also greatly endangers our human health.Therefore,the detection of heavy metal pollution has become a problem that can not be ignored,and its detection methods have attracted widespread attention,especially in the sensing field.At present,the detection methods of heavy metal ions still rely on large analytical and testing instruments,but this method is not only cumbersome in operation but also very expensive in detection cost.Therefore,the fluorescent sensor has become one of the important detection methods of heavy metals because of its unique advantages such as convenience to carry,low cost and high efficiency detection.In this paper,the preparation and properties of fluorescence sensing materials with heavy metal ion detection function are discussed.The main work is as follows:(1)Preparation of double emission ratio fluorescent nanoprobe.In this part,we use fluorescent silicon nanoparticles and carbon dots as raw material to design and build a new type of dual emission characteristics of the fluorescent probe,silicon nanoparticles and carbon dots via electrostatic interaction to form the overall assembly,which can produce double in a single excitation wavelength emission peak,dual emission silicon nanoparticles-carbon dots fluorescence probe.The fluorescent probe has a high fluorescence quenching for copper ions,so it can be used to detect copper ions sensitively and efficiently.The detection limit of silicon nanoparticles-carbon dots fluorescent nanoprobe can be as low as 10 n M,and it has a good application effect in actual water samples.As an excellent fluorescent nanoprobe,it can be used in multiple fields such as environmental monitoring,chemical analysis,medical diagnosis and food safety detection.(2)Preparation of polymer nanocomposite films.In this study,we used polymethacrylic acid as a stabilizer,using one-step method in situ synthesis of silver nanoclusters in the polyvinyl alcohol films,so silver nanoclusters doped polyvinyl alcohol composite films were successfully prepared.Its synthesis method is very simple,safe and pollution-free,low price,and easy to carry.Silver nanoclusters doped polyvinyl alcohol composite film has strong fluorescence quenching and high sensitivity to mercury ions,so we use it as a thin film sensor to detect mercury ions.In the presence of mercury ions,the fluorescence of the silver nanoclusters doped polyvinyl alcohol composite films composite film can be completely quenched,and the color of the film also changes accordingly,which can realize the dual detection of mercury ions fluorescence and vision.The detection limit of mercury ions in silver nanoclusters doped polyvinyl alcohol composite films can be as low as 4 n M.The silver nanoclusters doped polyvinyl alcohol composite films composite film prepared by us not only has a good detection effect but also are very convenient to carry,which provides a great development for the field detection for mercury ions.