基于LIBS的土壤中铜元素和铅元素定量分析

Quantitative Analysis of Cu and Pb in Soil Based on LIBS

利用激光诱导击穿光谱(LIBS,laser-induced breakdown spectroscopy)技术对掺杂Cu、Pb元素的土壤样品进行定量分析,寻找最优实验条件。实验使用直接定标法和内标法对元素特征谱线进行拟合,根据计算相关系数及检出限选择合适的数据处理方法。由实验结果可知,能量设定在70 m J,延迟时间为2μs可以达到元素谱线强度和信背比的最优实验条件。以Fe元素谱线作为内标校准曲线与直接定标相比,两种掺杂的重金属元素的拟合系数R2分别比直接定标提高了1.4%和3.7%。实验表明,通过Fe元素作为内标元素,能够降低激光器能量波动的影响,提高拟合精准度。

Laser-induced breakdown spectroscopy is used to quantitatively analyze soil samples doped with Cu and Pb elements,and the optimal experimental conditions are found.The direct and the internal calibration methods are used to fit elemental characteristic spectral lines.According to the calculation of correlation coefficient and detection limit,the suitable data processing method is chosen.The experimental results show that the optimal experimental conditions of elemental spectral line intensity and signal-to-background ratio can be achieved when the energy is set at 70 mJ and the delay time is 2μs.Compared with the direct calibration,the fitting coefficient R?is increased by 1.4%and 3.7%by using Fe spectral line as internal standard calibration curve.Experiments show that Fe element as the internal standard element can reduce the influence of laser energy fluctuation and improve the fitting accuracy.