传统的土壤重金属元素检测方法流程复杂,时间长。我们采用波长1 064 nm 的调Q 脉冲Nd:YAG 激光器和多通道小型光纤光栅光谱仪,建立了一套可移动的激光诱导击穿光谱系统。详细研究了重金属元素Ba、Mn 的特征谱线强度、标准偏差与数据采样方式以及采样平均次数的关系,在优化工作参数的基础上,采用一种新的光谱采样和数据处理方法,对土壤中金属Ba、Mn 的含量进行检测,并获得了检测土壤中金属Ba、Mn 含量的定标曲线,对元素Ba、Mn 的监测的相对标准偏差分别为9.0%和10.24%,检测灵敏度分别为19.4 mg/kg 和115.4 mg/kg,优于目前文献报道的结果。

The analysis of heavy metals in soil usually requires a complex procedure and digestion time if carried out by using traditional analytical techniques. In this paper,a moveable Laser-Induced Breakdown Spectroscopy (LIBS) instrument is established which is mainly equipped with a pulsed 1 064 nm Nd:YAG laser and a portable spectrometer,and has been applied for the quantitative measurement of Ba and Mn in soil. The intensity and relative standard deviations of the signal of Ba and Mn are carefully investigated by varying the way of data acquisition. Along with the experimental parameters optimization,a new data acquisition and processing method is used to improve the measurement precision and sensitivity. The calibration curves for quantitative measurement of Ba and Ma are derived. The measurement precisions,in terms of Relative Standard Deviations (RSD),are 9.0 % and 10.24% for Ba and Mn respectively. The Limits of Detection (LOD) for Ba and Mn in soil are improved to be 19.4 mg/kg and 115.4 mg/kg respectively,and are better than the results reported in literature.