Research On Rapid Detection Method And Application Of Heavy Metal In Water Environment Combined With Smartphone

Heavy metal pollution has become one of the serious problems facing the world.Heavy metal pollution has the characteristics of long-term,cumulative,latent and irreversible.It has great harm and high cost of treatment,and directly threatens human life and health.With the development of economy and society and the increasing awareness of environmental protection,these environmental pollution problems have received more and more attention.The detection of heavy metal ions in the water environment is not satisfied with the traditional methods,and the detection methods and techniques are transformed from a single detection method to the combination of a variety of new technologies,the development of simple,fast,portable detection systems has become the future development trend.The main research contents and innovative work of this paper are as follows:1.A portable electrochemical detection system combining smart phone terminals is designed to realize rapid detection of various heavy metal ions in water environment.This paper proposes a portable electrochemical detection system combining smart phone terminal.The system is composed of Android-based smartphone software,hardware circuit and multi-sensor part.It realizes various electrochemical analysis methods such as cyclic voltammetry(CV)and differential pulse voltammetry(DPSV).The actual samples of lead and cadmium ions in drinking water with silver electrode and mercury film glassy carbon electrode as working electrode were studied.The detection limits of lead and cadmium ions were lower than those required in China's"Sanitary Standard for Drinking Water".The experimental results show that the portable electrochemical detection system can meet the rapid detection of heavy metal ions in drinking,and compared with the traditional detection instruments and methods,it has the advantages of small volume and movable detection.2.The smartphone-based software system is designed,with the functions of signal data acquisition,visual display and data analysis,which improves the portability of the detection system.Based on the Android platform,this paper designs and implements the system control software using Java language,which can be used as a mobile terminal in the heavy metal electrochemical detection system.The software has functions such as transmission,detection control,data acquisition,visual display and data analysis.The mobile phone software uses multi-threading technology and socket technology to realize wireless communication with the lower computer,and uses the open source chart library(AchartEngine)to realize the real-time rendering and display of curve data.In addition,the software also implements functions such as parameter setting,historical data saving,data processing,and concentration calculation.Finally,it is connected with the hardware system to test and evaluate the overall function of the software.The experimental results show that the main functions of the mobile control software can be operated nonnally,the software operation is not difficult,and the use cost is significantly reduced.3.A visual detection method for nucleic acid aptamer-nanogold colorimetric sensor combined with smart phone is proposed to achieve high-throughput detection of cadmium ions in water environment.This paper designs a visual sensor system that combines smart phones and nanogold-nucleic acid aptamers for the detection of cadmium ions in water environments.The cadmium nucleic acid aptamer of the system is used as a specific recognition molecule,and the nano gold material is a medium,which is detected based on the colorimetric principle.In this paper,nano-gold particles were prepared by trisodium citrate reduction of chloroauric acid.The interaction mechanism of nucleic acid aptamers between gold and cadmium was studied and applied to the rapid detection of heavy metal cadmium ions in water environment.The results show that the absorbance ratio of the system has a good linear relationship with the concentration of cadmium ions.The linear range of detection is 2-20 ?g/L,and the detection limit is 1.15 ?g/L.It has certain application prospects in high-throughput detection.4.A quantum dot was explored as a fluorescent probe combined with a heavy metal couplant(EDTA)fluorescence sensor,which is expected to achieve specific and quantitative detection of trace cadmium ions in aqueous environments.In this paper,the design method of fluorescence detection sensor using CdTe quantum dots as fluorescent probes combined with metal couplants was studied.The mechanism and experimental conditions of fluorescence quenching and recovery of CdTe quantum dots were studied to improve the sensitivity of detecting cadmium ions.The experimental results show that the fluorescence recovery intensity of EDTA-CdTe quantum dots has a good linear relationship with the concentration of cadmium ions in the solution.The detection range is 20-400 ?g/L,and the detection limit is 13.7 ?g/L.In addition,the method uses a method of first quenching and recovery,which can avoid the influence of other factors on the test results.The experimental results show that the detection method has high selectivity to interfering metal ions,and is a detection method with fast response speed,simple operation,low cost,good repeatability and good selectivity.