基于LIBS与多元线性定标的稀土元素检测研究

Detection method of rare earth elements based on LIBS technology and multivariate linear calibration

稀土在工农业和军工等领域应用广泛,是重要的战略储备资源。然而,基于常规单元定标方法的激光诱导击穿光谱(LIBS)技术对痕量稀土元素进行高准确度检测仍充满挑战。本研究提出了优选多谱线建立多元线性定标模型,以提高La、Gd、Y、Yb四种稀土痕量元素的LIBS检测准确度。在优化离焦量、采集延时和激光脉冲能量实验参数的基础上,建立了这四种元素的多元线性定标模型,并基于验证样品对比了一元至三元条件下定标模型的均方根误差(RMSE)。结果显示,验证样品中La、Gd、Y和Yb四种元素的RMSE从一元线性定标时的0.00341%、0.00727%、0.00662%和0.00653%降至三元线性定标时的0.00203%、0.00707%、0.00586%和0.00356%。研究结果表明,利用LIBS多元线性定标模型可以有效降低稀土元素的预测误差,提高稀土痕量元素测量的准确性。

Rare earths are important strategic reserve resources,which are widely used in industry,agriculture,military,etc.However,high-precision detection of trace rare earth elements based on the combination of laser-induced breakdown spectroscopy(LIBS)technology and conventional unit calibration methods still remains challenging.A multivariate linear calibration model is established using preferred multispectral lines,replacing the conventional unit calibration methods,to improve the accuracy of LIBS detection for four rare earth trace elements(La,Gd,Y,Yb).On the basis of optimizing experimental parameters(defocus distance,acquisition delay,and laser pulse energy),a multivariate linear calibration model for the four elements was established,and the root mean square errors(RMSE)of the calibration model under one to three characteristic spectral lines are compared based on validation samples.The results show that the RMSE of La,Gd,Y,and Yb decreased from 0.00341%,0.00727%,0.00662%,and 0.00653%in the single linear calibration fitting to 0.00203%,0.00707%,0.00586%,and 0.00356%in the ternary linear calibration fitting model.This result indicates that the use of LIBS multivariate linear calibration model can significantly reduce prediction error of rare earth elements,and the detection accuracy of rare earth elements can be effectively improved.