Spectral Characteristic And Quantitative Analysis Of LIBS By Combining Magnetic Field And Au Nanoparticles

Laser-induced breakdown spectroscopy(LIBS),as an emerging elemental analysis technique,but it has low detection accuracy due to the shortcomings such as poor repeatability,large matrix effect and self-absorption effect,It is found that by increasing the intensity and signal-to-noise ratio of the spectrum,the detection limit of the analytical element can be effectively reduced and the accuracy of quantitative analysis can be improved.Aiming at the need of LIBS spectral enhancement and signal-to-noise ratio improvement,magnetic enhanced LIBS(MF-LIBS)with nanoparticle enhanced LIBS(NELIBS)was combined,and systematically studies of spectral signal characteristics and quantitative analysis accuracy of the combined mode were conduced.The 0.3 T magnetic field was combined with the 20 nm diameter Au nanoparticles in the LIBS technology.The pure copper was used as the test sample,and the Cu I 515.1nm was used as the analytical line.Compared with the traditional LIBS technology,the enhancement factor and the signal-to-noise ratio varies with the laser energy were studied,as well as the temporal evolution of plasma electron temperature and electron density,and causes of the changes was also analyzed,when the NELIBS was combined with MF-LIBS.The results show that the spectrum under the combined mode is greatly enhanced and the signal-to-noise ratio is improved significantly.The Local Thermal Equation(LTE)was judged by the Mc-Whirter criterion,and the results showed that the experiments were all performed in the LTE.The stainless steel was used as a sample to investigate the quantitative analysis accuracy andthe change of Ni element detection limit when MF-LIBS combined with NELIBS.Ni I221.648 nm was selected as the analytical element line,Fe II 258.588 nm as the internal standard element line,and the internal standard legal curve was drawn using the stainless steel sample 303 SS,304 SS,316 SS,321 SS spectral data,Ni II 221.648 nm was used to plot the calibration curve of the absolute intensity method(external standard method).The standard spectral sample 347 SS spectral data was taken into the internal standard legal standard curve to calculate the Ni element concentration value,and the SD,RSD,ARE,RMSEP and other indicators were calculated to evaluate the quantitative analysis accuracy under the combination of MF-LIBS and NELIBS.The brass was used for the qualitative analysis of elemental detect of limit,and internal standard spectral data were used to quantitative analysis of Ni element limit of detection.The results show that the precision of quantitative analysis of Ni element in the combined mode is improved,and the limit of detection is effectively reduced.