Design Of Hg²⁺ Detection System Based On Fluorescence Quenching

Since the reform and opening up, the rapid economic development has brought the growing problems of environmental pollution, seriously affecting the ecological balance and environmental safety of our country, restricting the sustainable development of the economy. It has caused a very serious impact on the health status of the people, and become a major problem of current society. In recent years, safety incidents of agricultural product show a high incidence trend, and become the most direct impact of environmental pollution in people’s daily lives. The adverse consequences of these events sound the alarm for environmental pollution control. Heavy metal pollution is a major cause of environmental pollution. Heavy metal accumulates in the human body through the food chain.Excessive heavy metals in the human body can bring about various diseases to health, and cause great threats. In order to achieve fast and accurate detection of heavy metal pollution level of the environment, this paper makes full use of quantum dot fluorescence quenching characteristics combining with embedded technology,then designs a device for rapid detection of Hg2+, on the basis of a full investigation about heavy metal detection technology and trendsat home and abroad.Firstly, according to the detection principle, we design the optical sensing module and finish the quantum dot fluorescence quenching.To resolve the problems which can’t be detected by the weak fluorescence signal,the design of the corresponding signal conditioning circuits can achieve the conversion, amplification and noise reduction of weak optical signal.Because the unstable test results caused by redshift phenomenon,which brought by elevated temperature when the core components of detection semiconductor laser works,it’s necessary to design appropriate temperature control module to control the temperature, consequently improve the overall stability of the detection means.Secondly, combining the advantages of embedded devices and the actual needs determine the design of detection device software system in this paper.After comprehensive consideration,based on the embedded Linux system, after cutting, graft, writing file system, building software systems, developing and designing application complete the entire operating system of graft and establishment process. System applications using Qt complete the detection, display, communication and other functions.Finally, this paper starts the mercury ion detection experiment, analyzes the linear relationship between the mercury ion concentration and the fluorescence intensity, then comes to the range and detecting limit of linear detection. Through the selectively experimental section, we demonstrate the influence and shielding methods of other heavy metal ions, exclude the interference of other heavy metal with the detection of the standard values, conduct the validation experiments of the actual field test results. It proves in this paper that detection device has achieved the expected results, and has some practical significance and application prospects.