基于电极富集的水体重金属LIBS检测灵敏度研究

发布时间：2018-09-04 06:18

【摘要】：为了提高水体重金属LIBS检测的灵敏度以及降低元素检测限,采用LIBS结合铝电极富集方法对水体中的重金属Pb,Cd,Ni进行了分析。研究并优化了电极富集方法中关键参数—富集电压U,分析了LIBS特征谱线的光谱强度与富集电压大小之间的关系,得出重金属元素特征光强随着富集电压先增加后减小,在1.2 V处光谱强度达到最大值,选择了最优富集电压值为1.2 V。研究了Pb,Cd,Ni三种重金属元素的光谱稳定性,其特征谱线光谱强度的相对标准偏差(RSD)分别为5.98%,4.25,%和5.27%,说明该实验方法得到的谱线具有较高的稳定性。在0~0.13 mg·L~(-1)范围内配制系列样品进行实验并对元素进行定量分析,得到Pb,Cd,Ni三种重金属元素的检测限分别为1.2,3.1和1.7 ppb。结果表明:LIBS结合铝电极富集方法能够有效地提高特征谱线的稳定性以及降低元素的检测限,为提高水体重金属LIBS的检测灵敏度和分析能力提供了方法支持。
[Abstract]:In order to improve the sensitivity of LIBS detection of heavy metals in water and reduce the detection limit of elements, LIBS combined with aluminum electrode enrichment method was used to analyze the heavy metal Pb,Cd,Ni in water. This paper studies and optimizes the key parameter in the method of electrode enrichment-enrichment voltage U, and analyzes the relationship between the spectral intensity of the LIBS characteristic line and the enrichment voltage. It is concluded that the characteristic light intensity of heavy metal element increases first and then decreases with the enrichment voltage. The spectral intensity reaches the maximum at 1.2 V, and the optimum enrichment voltage is 1.2 V. The spectral stability of three heavy metal elements in Pb,Cd,Ni was studied. The relative standard deviation (RSD) of the spectral intensity of the characteristic spectral lines was 5.98% 4.25% and 5.27% respectively, which indicated that the spectral lines obtained by the experimental method had high stability. A series of samples were prepared in the range of 0. 13 mg L ~ (-1) for quantitative analysis of elements. The detection limits of three heavy metal elements in Pb,Cd,Ni were 1.23.1 and 1.7 ppb., respectively. The results show that the composition of LIBS in water body can effectively improve the stability of characteristic spectral lines and reduce the detection limit of elements, which provides a method support for improving the detection sensitivity and analytical ability of heavy metal LIBS in water.
【作者单位】：中国科学院环境光学与技术重点实验室中国科学院安徽光学精密机械研究所安徽省环境光学监测技术重点实验室;
【基金】：安徽省科技攻关项目(1501041119) 安徽省科技重大专项项目(15CZZ04125) 安徽省杰出青年科学基金滚动支持项目(1508085JGD02) 国家自然科学基金项目(60908018) 国家“863”计划项目(2013AA065502,2014AA06A513)资助
【分类号】：X832;O433.4

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