Chemical attribution of the homemade explosive ETN - Part II: Isotope ratio mass spectrometry analysis of ETN and its precursors.

In this follow-up study the collaboration between two research groups from the USA and the Netherlands was continued to expand the framework of chemical attribution for the homemade explosive erythritol tetranitrate (ETN). Isotope ratio mass spectrometry (IRMS) analysis was performed to predict possible links between ETN samples and its precursors. Carbon, nitrogen, hydrogen and oxygen isotope ratios were determined for a wide variety of precursor sources and for ETN samples that were prepared with selected precursors.

Split-root labelling to investigate N rhizodeposition by Pinus sylvestris and Picea abies.

We investigated the transfer of N into the soil via N uptake and release by tree roots, which involves the principles of the split-root technique. One half of the root system received an injection of (NH)SO and the other half equivalent amounts of (NH)SO at N natural abundance level. N was transferred from one side of the root system (N side) to the other side (N side) and released into the soil.