Rapid screening method for heavy metals in contaminated soils using LIBS

Laser-induced breakdown spectrometry (LIBS) has been used to analyze soil a erosols generated inside sealed vials. The reproducibility of the method wa s shown to be 2-3 times better than using pressed samples. The advantages o f the method include a great simplicity as the sample can be directly taken from the location site, the capability for analysis without any manipulati on other than sieving, and the absence of contamination risk with highly po lluted soils as there is no direct contact during the analysis, and the res idues are confined inside the vial. Linear calibration curves between 1-100 0 ppm for Cr, Cu, Ni, Sr and Pb were obtained, as well as detection limits in the range between 5 and 20 ppm with correlation coefficients better than 0.99. A strong dependence of the spectra with grain size was observed.