应用LIBS技术测量土壤重金属Cr含量

The Detection of Heavy Metals in Soil with Laser Induced Breakdown Spectroscopy

应用激光诱导击穿光谱分析技术(1aser-induced break-down spectroscopy,LIBS)开展了土壤中重金属铬元素含量探测研究。实验中激光波长为1 064 nm,脉冲宽度为8 ns,重复频率10 Hz,选取Cr 427.4 nm作为光谱分析谱线。实验结果表明,在光谱采集相对于激光脉冲延迟时间为4.78μs,土壤样品表面位于聚焦透镜焦后1 mm的实验条件下,Cr元素浓度测量的相对标准偏差(RSD)为12.1%,检测限为2.01 ppm,元素实验测量与标准值的相对偏差为5.15%。可以看出LIBS技术具有低检测限、测量精度高等优点,这对土壤中重金属污染和监测环境质量的精确、快速检测等问题具有重要意义。

The elemental concentration of Cr contained in soil is measured with laser induced breakdown spectroscopy（LIBS）.As the LIBS laser power,the laser wavelength is of 1 064 nm with pulse width of 8 ns and laser repetition frequency of 10 Hz in this experiment and Cr 427.4 nm is selected as the analytical line of LIBS.The experimental results show that the relative standard deviation（RSD） of the detected content of Cr is 12.1%at the delay time of 4.78 μs and the soil sample surface 1 mm behind lens focal point.The limit of detection（LOD） of LIBS is 2.01 ppm.The measured relative deviation between the measured value and the nature value is 5.15%.Because the LIBS has advantages such as lower LOD and higher detection precision,LIBS has a guiding significance to detect heavy metal in soil and to monitor environmental quality precisely and rapidly.