Analysis of Soils and Sediments by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS): An Innovative Tool for Environmental Forensics

This article describes the applicability of a rapid laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method for the analysis of soil and sediment samples with broad chemical and physical properties and the comparison of its analytical performance to digestion protocols commonly used in environmental sciences. Two sets of samples were evaluated, contaminated soils from a residential area and undisturbed sediments from natural environments. Analytical results obtained by LA-ICP-MS correlate well at the 95% confidence level to total digestion followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and ICP-MS analysis. A total of 48 sediments collected in South Florida were also analyzed for screening purposes and to evaluate the application of LA-ICP-MS in environmental forensics. Normalization using Al combined with non-parametric correlation tests and principal component analyses were successfully used to predict correlations between data acquired by LA-ICP-MS and by partial digestion methods followed by ICP methods. Precision and accuracy for the LA method was 20%, which is typically accepted for digestion methods of soils and sediments. The overall bias, evaluated on reference standard materials, ranged from 8%-15%. The overall precision obtained on samples was 10% relative standard deviation (RSD).