中国激光, 2017, 44 (11): 1111002, 网络出版: 2017-11-17
基于激光诱导击穿光谱定量检测土壤中营养元素的研究 下载: 982次
Quantitative Detection of Nutrient Elements in Soil Based on Laser Induced Breakdown Spectroscopy
光谱学 激光诱导击穿光谱 稳定性分析 定量分析 定标曲线 spectroscopy laser induced breakdown spectroscopy stability analysis quantitative analysis calibration curve
摘要
采用激光诱导击穿光谱(LIBS)对土壤中的营养元素进行了定量检测。采用输出波长为1064 nm、脉宽为5.82 ns的Nd∶YAG脉冲激光器作为光源, 将激光聚焦在土壤表面产生激光诱导等离子体, 使用三光栅光谱仪和门宽控制的增强电荷耦合器件(ICCD)测量等离子体发射光谱。基于传统LIBS系统, 新增了扩束镜系统和实时监测系统, 研制了笼式结构LIBS系统, 优化了笼式结构中扩束镜系统的激光聚焦位置, 获得了最佳的激光聚焦位置0.2 cm。测试了Mg II 279.56 nm、Mg II 280.26 nm和Mg I 285.21 nm谱线的信号强度。结果表明, 笼式结构LIBS系统在信号稳定性上优于传统LIBS系统。定量分析了土壤中营养元素Cu、Mn、Mg、K的质量分数, 它们的检出限分别为0.42×10-6、13.2×10-6、38.5×10-6、62×10-6, 优于传统LIBS系统得到的检出限。基于定标模型预测了土壤中Cu、Mn、Mg、K元素的质量分数, 它们预测值的平均相对误差分别为9.2%、9.6%、8.5%、10.9%。
Abstract
The nutrient elements in the soil are quantitatively detected by laser induced breakdown spectroscopy (LIBS). The Nd∶YAG pulsed laser with output wavelength of 1064 nm and pulse width of 5.82 ns is used as light source to focus on the surface of the soil to generate laser induced plasma. The plasma emission spectra are measured with utilization of a three grating spectrometer and a gate width controlled intensified charge-coupled device (ICCD). On the basis of traditional LIBS system, beam expander system and real-time monitoring system are added to form LIBS system with cage structure. The focusing position of laser in LIBS system with cage structure is optimized, the optimum laser focusing position is 0.2 cm. The signal intensities of Mg II 279.56 nm, Mg II 280.26 nm and Mg I 285.21 nm spectral lines are tested. The results show that the LIBS system with cage structure is superior to the traditional LIBS system in signal stability. The detection limits of Cu, Mn, Mg and K elements in soils are 0.42×10-6, 13.2×10-6, 38.5×10-6, 62 ×10-6, respectively, which are better than the detection limits obtained by traditional LIBS system. The mass fractions of Cu, Mn, Mg and K elements in soils are predicted based on the calibration model, the average relative errors of the elements are 9.2%, 9.6%, 8.5%, and 10.9%, respectively.
王金梅, 颜海英, 郑培超, 谭癸宁. 基于激光诱导击穿光谱定量检测土壤中营养元素的研究[J]. 中国激光, 2017, 44(11): 1111002. Wang Jinmei, Yan Haiying, Zheng Peichao, Tan Guining. Quantitative Detection of Nutrient Elements in Soil Based on Laser Induced Breakdown Spectroscopy[J]. Chinese Journal of Lasers, 2017, 44(11): 1111002.