Analytical Instrument Documents

Smokeless powders are often used in improvised explosive devices. The formulations for smokeless powders vary between manufacturers and between brands from a given manufacturer; ingredients include energetics, stabilizers, plasticizers and deterrents. Both chemical composition and morphology are important in characterizing smokeless powders. Chemical analysis of smokeless powders can provide valuable forensic evidence. Observation with the SEM can reveal morphological information to help with identification. Here we show how SEM-EDS analysis can be used to identify inorganic components, and how the AccuTOF-DART mass spectrometer can rapidly identify the organic components and provide a chemical fingerprint that can be used to identify individual powder particles.

A batch of contaminated welding wire received from a vendor by a customer was causing problems in a manufacturing process. Visual comparison of the clean and contaminated wire did not show any obvious differences, but the contamination was readily observed on backscatter electron images obtained with the JEOL IT300 scanning electron microscope.

The identification of pressure-sensitive tapes such as duct tape and electrical tape is an important forensic application. Here we show the application of thermal desorption and pyrolysis combined with Direct Analysis in Real Time (DART) mass spectrometry to distinguish between manufacturers and brands of duct tapes. X-ray fluorescence (XRF) provides complementary information about the atomic composition of the different tapes.