Research On Spectral Detection Of Metal Elements Based On SCGD System

With the rapid development of modern industry and agriculture,water pollution is aggravated.Excessive metal elements in water can damage the body's function and nervous system,and people's health is seriously affected.Therefore,rapid and accurate detection of metal elements in water is necessary.Solution cathode glow discharge(SCGD)is an emerging detection technology for atomic emission spectroscopy in recent years.Due to its advantages of small device size,low cost,simple and quick detection,it has been paid much attention and researched by domestic and foreign scholars.At present,the spectral detection technology of SCGD has achieved some achievements and is widely used in water quality detection of various substances and environments.However,due to the detection capability and stability of the SCGD device needs to be improved,so the technology is still in the laboratory research stage.In this thesis,the currently existing problems of SCGD technology are studied,and the main contents are as follows:1.In this thesis,the experimental device has been improved.The optimized pulsation damper was added between peristaltic pump and capillary glass to eliminate the influence of the pulsating flow generated by the peristaltic pump squeezing hose,and the shake of the cathode liquid level was solved.The performance of the improved SCGD system was tested.The results show that the SCGD system can work in good stability for a long time and has better performance parameters.2.In this thesis,according to the influence factors of SCGD system,the effects of acidification reagents,solution flow rate and discharge current on atomic emission spectrometry were investigated in detail,and experimental parameters were optimized for them.The phenomenon of self-absorption of the atomic emission spectra was studied.It was found that when the concentration of the sample was too high,the phenomenon of self-absorption in glow discharge was obvious,which caused the sample concentration and spectral intensity not to be linear and impacted detection results.Then,the detection limits(DL)of Zn,Mg,Ag,Pb,Sr,Na,Li,K,Rb and Cs in the solution under the optimal experimental conditions were obtained.Finally,the quantitative detection of Ag(GSB04-1712-2004),Zn(GSB04-1761-2004)and Pb(GSB04-1742-2004)in the calibration material shows that the SCGD system has a good accuracy and stability.3.In order to further improve the detection sensitivity of metal elements,the effects of organic reagents such as formic acid,acetic acid and ethanol on atomic emission spectra were studied.The relationship between the organic reagents' concentration and their emission spectral intensities was investigated.Getting the best amount of organic concentration and added it in Pb,Ag,Cd,Fe solutions for testing,and the experimental results show that organic reagents can increase the sensitivity of metal elements to some extent.In this thesis,the plasma electron excitation temperature in SCGD system was also studied.The spatial distribution of electron excitation temperature was observed and analyzed.The effects of three organic reagents,discharge current and solution flow rate on the electron excitation temperature were also investigated.