Heavy metal concentrations in soils as determined by laser-induced breakdown spectroscopy (LIBS), with special emphasis on chromium.
Heavy metal concentrations in soils as determined by laser-induced breakdown spectroscopy (LIBS), with special emphasis on chromium.
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DOI：
10.1016/j.envres.2009.02.005
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发表时间：
2009-05
影响因子：
8.3
通讯作者：
G. Senesi;M. Dell’Aglio;R. Gaudiuso;A. Giacomo;Claudio Zaccone;O. Pascale;T. Miano;M. Capitelli-M.-Capitell
中科院分区：
文献类型：
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作者：
G. Senesi;M. Dell’Aglio;R. Gaudiuso;A. Giacomo;Claudio Zaccone;O. Pascale;T. Miano;M. Capitelli-M.-Capitell
土壤被公认为人类活动释放重金属的重要汇之一。天然和污染土壤的重金属分析通常通过使用原子吸收光谱法（AAS）或电感耦合等离子体发射光谱法（ICP-OES）对充分获得的土壤提取物进行。近年来，激光诱导击穿光谱（LIBS）技术在土壤基质中重金属的定性和定量分析中得到了广泛的应用，并取得了一定的成功。这项工作的主要目的是证明，在LIBS技术的新发展是能够提供可靠的定性和定量分析评价土壤中的几种重金属，特别关注元素铬（Cr），并参考传统的ICP光谱测量的浓度。五个土壤样品和一个污水污泥样品的初步定性LIBS分析，允许检测的一些元素，包括铝，钙，铬，铜，铁，镁，锰，铅，硅，钛，V和锌。其中，基于为每种重金属构建的校准曲线的所获得的线性，也可以对元素Cr、Cu、Pb、V和Zn进行定量分析，即，LIBS发射峰的强度与通过ICP测量的样品中每种重金属的浓度之间的比例。特别地，Cr的三重发射谱线可用于其定量测量。激光诱导等离子体（LIP）的相同特性支持了对各种样品进行的实验的一致性，即，典型的线性分布证实了局部热力学平衡（LTE）条件的存在，以及相似的激发温度和可比的电子数密度测量所有样品。污染土壤中铬的人为贡献的指数计算相比，非污染的参考土壤。因此，重金属发射线的强度比可以用于在几分钟内检测污染区域，对于该污染区域，更详细的采样和分析可以是有用的。
Soil is unanimously considered as one of the most important sink of heavy metals released by human activities. Heavy metal analysis of natural and polluted soils is generally conducted by the use of atomic absorption spectroscopy (AAS) or inductively coupled plasma optical emission spectroscopy (ICP-OES) on adequately obtained soil extracts. Although in recent years the emergent technique of laser-induced breakdown spectroscopy (LIBS) has been applied widely and with increasing success for the qualitative and quantitative analyses of a number of heavy metals in soil matrices with relevant simplification of the conventional methodologies, the technique still requires further confirmation before it can be applied fully successfully in soil analyses. The main objective of this work was to demonstrate that new developments in LIBS technique are able to provide reliable qualitative and quantitative analytical evaluation of several heavy metals in soils, with special focus on the element chromium (Cr), and with reference to the concentrations measured by conventional ICP spectroscopy. The preliminary qualitative LIBS analysis of five soil samples and one sewage sludge sample has allowed the detection of a number of elements including Al, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Si, Ti, V and Zn. Of these, a quantitative analysis was also possible for the elements Cr, Cu, Pb, V and Zn based on the obtained linearity of the calibration curves constructed for each heavy metal, i.e., the proportionality between the intensity of the LIBS emission peaks and the concentration of each heavy metal in the sample measured by ICP. In particular, a triplet of emission lines for Cr could be used for its quantitative measurement. The consistency of experiments made on various samples was supported by the same characteristics of the laser-induced plasma (LIP), i.e., the typical linear distribution confirming the existence of local thermodynamic equilibrium (LTE) condition, and similar excitation temperatures and comparable electron number density measured for all samples. An index of the anthropogenic contribution of Cr in polluted soils was calculated in comparison to a non-polluted reference soil. Thus, the intensity ratios of the emission lines of heavy metal can be used to detect in few minutes the polluted areas for which a more detailed sampling and analysis can be useful.