|Abstract inglese (opzionale):
Characterizing recovered explosives from a bombing or accidents and finding distinctive markers is crucial to clarify the threat and to follow up the emergency.
Here we want to focus on the discrimination of an explosive using specific isotope ratio as carbon (d13C), nitrogen (N) ones. The capability of stable isotope ratios analysis to differentiate the composition of a chemical compound and to mark different origin and processes is well known in agrifood and materials science and to counterfaction investigations.
The most used methodologies implies the use of isotope ratios mass spectrometers that are equipment designed specifically for working in laboratory environment. The goal of our work is to design and implement a new methodology to analyze d13C on site using a Carbon Dioxide Isotope Analyzer (CCIA) CRDS laser spectrometer (Los Gatos Research, California, US) and similar analytical spectroscopy techniques.
The CCIA-36 EP (Enhanced Performance) model allows to measure d13C, d18O, CO2 and H2O in real time with great accuracy and speed of measurement up to 1 hertz and it’s transportable directly on the accident site. The instrument is based on the Off-Axis Integrated Cavity Output Spectroscopy (Off-Axis ICOS) as absorption cell, which traps the laser photons so that thousands of steps are carried out before leaving the cell. This new technique allow a better measure of the absorption line.
Interfacing an elementary combustor to a specifically designed CRDS laser spectrometer may also allow the sampling on site of suspected materials and the analysis of carbon and nitrogen isotope ratios of the component of explosive.
The proposed instrumental configuration can be used as transportable system to run isotopic analysis in working environment of emergency situation and with fast response time, in order to assess the origin and the manufacturer of the explosive materials or components.