Rapid Detection Of Heavy Metals In Polluted Water Based On LIBS Technology

Laser Induced Breakdown Spectroscopy(LIBS)is widely used in environmental pollution detection because it has the advantages of accurate,fast,and simultaneous real-time remote detection of multiple elements.This article uses LIBS technology to conduct elemental analysis of polluted water simulated by a mixed solution consisting of Cd,Mn and Cu elements.The main research contents are as follows:1)This article uses C# language to program the LIBS system instrument control software,complete the control of the Avantes spectrometer and the DG645 digital pulse delayer,and then use the LIBS system control software to study the Cd,Mn and Cu elements in the aqueous solution by the liquid jet injection method.We selected three spectral lines of Cd II 226.50 nm,Mn II 259.37 nm,and Cu I 324.75 nm as experimental analysis spectral lines,and optimized the experimental parameters such as laser breakdown position,laser energy,and liquid jet velocity to obtain the best experimental parameter conditions.2)The spectrum information obtained in the experiment cannot be used directly,and the spectrum needs to be pre-processed.This paper uses a third-order minimal background removal algorithm to perform baseline correction,wavelet transform and other filtering algorithms for denoising processing,and then uses the Voigt function to perform spectral peak fitting on the processed spectral data to obtain the element characteristic peak wavelength,intensity and half Peak full width and other characteristic values,then use the obtained characteristic data to perform similarity analysis with the NIST database,and combine spectral line correlation detection to identify elements in the spectrum.Then,two kinds of experimental spectral data under the LIBS mode and generalized integration of the spectrometer were used for element identification,and the algorithm recognition success rates were 94.7% and 89.2%,respectively.3)We use external and internal standard methods to quantitatively analyze the mixed solution containing Cd,Mn,and Cu elements under the optimal experimental conditions,and comprehensively calibrate the model to fit the accuracy and error analysis to obtain the best quantitative of the three elements The analysis conditions are: Cd element(external standard method,analysis line: Cd II 226.50nm),Mn element(internal standard method,analysis line: Mn II 259.37nm),Cu element(external standard method,analysis line: Cu I 327.40nm)The corresponding analysis result is Cd II 226.50nm: the fitting accuracy R2 value is 0.9955,the RMSEC,RMSEP and ARE values are 0.9034wt%,0.6236wt% and 4.7162%;Mn II 259.37nm: the fitting accuracy R2 value is 0.9953,RMSEC,RMSEP and ARE values are 0.9287wt%,0.9295wt% and 3.9598% respectively;Cu I 327.40nm: fitting accuracy R2 value is 0.9972,RMSEC,RMSEP and ARE values are 0.7071wt%,1.0233wt% and 4.5404 %.4)This paper uses Matlab and C# mixed programming to realize the research of LIBS element analysis software,completes the integration of the algorithm,realizes the rapid element identification and quantitative analysis of heavy metal elements in aqueous solution,and provides the conditions for LIBS technology to perform real-time water pollution detection,Promoted the development of LIBS technology applications.