图像辅助激光诱导击穿光谱校正的水中U定量分析

Image-Assisted Laser-Induced Breakdown Spectroscopy Correction for Quantitative Analysis of Uranium in Water

摘要:

激光诱导击穿光谱技术在水中低浓度重金属元素的定量分析中面临特征谱线强度波动大和检测结果不稳定的问题，限制了其实际应用。本文研究了等离子体图像特征与铀元素特征谱线强度之间的相关性，建立了等离子体图像多特征参数融合的谱线强度校正模型，并对U II 367.007 nm和U II 409.013 nm谱线强度进行了校正。结果表明，校正后U II 367.007 nm、U II 409.013 nm谱线强度的平均相对标准偏差分别由13.21%、13.13%%降低至6.58%、7.36%，特征谱线强度稳定性得到了提升。在此基础上，对水中铀元素进行定量分析，校正后U II 367.007 nm、U II 409.013 nm的定标曲线线性拟合度R2分别由0.989、0.976提高至0.995、0.993，检出限分别由17.66μg/L、16.95 μg/L降低至11.03 μg/L、7.55 μg/L，有效降低了水中低浓度铀元素的检测下限，提高了定量分析精度。

Abstract:

Laser-induced breakdown spectroscopy (LIBS) faces challenges due to large fluctuations in characteristic spectral line intensity and unstable detection results in the quantitative analysis of low-concentration heavy metals in water, limiting its practical application. This study investigated the correlation between plasma image features and the characteristic spectral line intensities of uranium. A model to correct spectral line intensities was established by integrating multiple plasma image features, and the U II 367.007 nm and U II 409.013 nm spectral line intensities were corrected. The results show that after correction, the average relative standard deviation of the spectral line intensities for U II 367.007 nm and U II 409.013 nm decreased from 13.21% and 13.13% to 6.58% and 7.36%, respectively, resulting in enhanced stability of the characteristic spectral line intensities. Based on this, quantitative analysis of uranium elements in water was conducted. After calibration, the linear fitting R2 of the calibration curves for U II 367.007 nm and U II 409.013 nm improved from 0.989 and 0.976 to 0.995 and 0.993, respectively. The detection limits decreased from 17.66 μg/L and 16.95 μg/L to 11.03 μg/L and 7.55 μg/L, respectively, effectively lowering the detection limit for low-concentration uranium in water and improving the accuracy of quantitative analysis.