Rapid screening method for heavy metals in contaminated soils using LIBS

Laser-induced breakdown spectrometry (LIBS) has been used to analyze soil aerosols generated inside sealed vials. The reproducibility of the method was shown to be 2-3 times better than using pressed samples. The advantages of the method include a great simplicity as the sample can be directly taken from the location site, the capability for analysis without any manipulation other than sieving, and the absence of contamination risk with highly polluted soils as there is no direct contact during the analysis, and the residues are confined inside the vial. Linear calibration curves between 1-1000 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.