激光诱导击穿光谱技术测定土壤中元素Cr和Pb

摘要

为了检验激光诱导击穿光谱技术对物质成分的检测能力,采用Nd:YAG激光器在优化实验条件下激发产生土壤等离子体,通过等离子体原子发射光谱法定量分析了国家标准土壤样品中元素Cr和Pb.实验中绘制了以Fe原子谱线为内标、分析谱线背景为内标以及没有内标的3种情况下的元素定标曲线,并确定了方法的精密度和检出限.结果表明,3种情况下分析元素Cr的相对标准偏差分别为5.85％、26.48％和33.10％,元素Pb的相对标准偏差分别为5.42％、22.78％和38.66％,证明采用内标法可以明显提高测量精度.用Fe谱线为内标时得到的元素Cr和Pb的相对检出限分别为3.50×10-3％和57.90×10-3％,满足微量元素分析要求.%To examine the capability of laser-induced breakdown spectroscopy on detection,soil plasma was deduced using Nd:YAG laser under optimal conditions,and then the content of element Cr and Pb in the national standard soil samples was analyzed by the method of plasma atomic emission spectrometry.The calibration curves were respectively drawn with Fe atomic spectral line,spectral lines background and nothing as internal standard.The precision and detection limit of the method were established.The results demonstrate that the values of relative standard deviation of element Cr are 5.85％,26.48％ and 33.10％,and the corresponding values of Pb are 5.42％,22.78％ and 38.66％ respectively under these three conditions,which indicates that the internal standard method can improve the precision of the measurement.The detection limits by Fe atomic line as internal standard are 3.50×10-3％ for Cr and 57.90×10-3％ for Pb,which meets the requirements of trace element analysis.