Meng Deshuo, Zhao Nanjing, Ma Mingjun, Fang Li, Gu Yanhong, Jia Yao, Liu Jianguo, Liu Wenqing
Appl Opt. 2017 Jun 20;56(18):5204-5210. doi: 10.1364/AO.56.005204.
In this work, a mobile laser-induced breakdown spectroscopy (LIBS) system has been successfully applied to in situ analysis of heavy metals in soil samples. The LIBS system had two working methods, which were a fixed measuring method and a handheld method. For the fixed measuring method, a simple sample pretreatment was needed to reduce the soil matrix effect generated by moisture and porosity. Experiments proved that this method could be used to semi-quantitatively detect heavy metals when combined with the traditional calibration curve method. The limits of detection for copper, lead, and zinc were all below 10 mg/kg, which satisfied the need of heavy metal detection in soil. Principal component analysis was used for soil classification, which helped to build appropriate calibration curves. On the basis of soil classification, accurate and rapid detection of heavy metals in soil is feasible. For the handheld method, spectrum intensity and stability decreased significantly compared with the fixed measuring method. However, by using the internal standard method, the stability of LIBS data was improved significantly to 6%. For soil samples with serious heavy-metal pollution, the measurement errors were less than 12%, which indicated that handheld LIBS was effective to monitor heavy-metal pollution in soil. The research results provide application support for rapid and on-site monitoring of heavy metals in soil.
在这项工作中，一种移动激光诱导击穿光谱（LIBS）系统已成功应用于土壤样品中重金属的原位分析。该LIBS系统有两种工作方式，即固定测量法和手持式测量法。对于固定测量法，需要进行简单的样品预处理以减少由水分和孔隙率产生的土壤基体效应。实验证明，该方法与传统校准曲线法结合可用于重金属的半定量检测。铜、铅和锌的检测限均低于10 mg/kg，满足土壤中重金属检测的需求。采用主成分分析进行土壤分类，有助于建立合适的校准曲线。基于土壤分类，准确快速地检测土壤中的重金属是可行的。对于手持式测量法，光谱强度和稳定性与固定测量法相比显著下降。然而，通过使用内标法，LIBS数据的稳定性显著提高至6%。对于重金属污染严重的土壤样品，测量误差小于12%，这表明手持式LIBS对监测土壤中的重金属污染是有效的。研究结果为土壤中重金属的快速现场监测提供了应用支持。
