Аннотация:Nowadays Laser-induced breakdown spectrometry (LIBS) is widely used for direct analysis of various environmental samples, such as sands, soils, glasses, rocks, etc. [1] The main goal of this work is to check the possibility of single-shot LIBS measurement in order to determine the traces of several toxic metals in accordance with official regulations of European Union and Russian Federation for soil contaminations. Standard samples of different soils from several Russian regions, such as podzol, grey forest, black agricultural etc., and strongly contaminated NIST and BAM soils were analysed by LIBS within three spectral windows (213 nm for Zn, 313 nm for Be, 405 nm for Pb) selected previously. Ablation of samples by 1064 nm, 532 nm and 355 nm of Nd:YAG laser was compared with respect to plasma parameters and ablation rate. There were no clear differences in plasma temperature and electron density evolution, but ablation rate was increased from longer wavelength to shorter wavelength. To estimate accuracy of single-shot measurement five points on the sample were used. Several internal standards lines with appropriate energy of upper level belonged to the same spectral window [2] were compared for each analytes. In a result of our work, third harmonic of Nd:YAG laser for ablation can provide minimal LODs of Pb, Be and Zn (8, 0.3, 37 ppm, respectively) for single-shot measurements. This work was financially supported by Russian Foundation for Basic Research (grant No 11-03-01187-a) and Ministry of Education and Science of Russian Federation (contract No 14.740.11.1087).
[1] D.W. Hahn, N. Omenetto, Appl. Spectrosc., 66, 347–419, (2012).
[2] N. B. Zorov, A. A. Gorbatenko, T. A. Labutin and A. M. Popov, Spectrochim. Acta, 65(B), 642-657, (2010).