Nitrate and Ammonium Ion Detection

Nitrate ions and ammonium ions are usually present in traces of an explosion of composite explosives containing ammonium nitrate as a component.

On the other hand, substances of organic and inorganic nature are widely used in everyday life and the national economy, which either directly contain the above-mentioned ions (for example, ammonium nitrate fertilizers) or form them in the process of their decomposition (for example, aniline dyes, nitro-lacquers, etc.).

It is not possible to unambiguously determine the origin of the detected ions based on the results of physicochemical studies.

Detection of Inorganic Combustion Products

To detect condensed combustion products of inorganic components of explosives and pyrotechnic compositions (for example, aluminum, magnesium) or their unburned particles, studies were conducted on deposits of inorganic substances on paper filters remaining after filtration of washings. The studies were conducted by the EPMA method on a JSM-840 scanning electron microscope from Jeol (Japan) with an ISIS microprobe analyzer from Oxford Instruments (UK) according to standard methods. Accelerating voltage - 20 kV. Elements determined - from beryllium to uranium.

Sample Preparation

Preparation of samples for studies of deposits on filters was carried out as follows. Each of the filters was placed in a test tube with alcohol and subjected to ultrasound to separate particles from the filter surface and from each other. After this, the alcohol suspension containing microparticles was applied to the surface of the stage of the electron microscope. After the suspension dried, microparticles were present on the surface of the stage in the form of a monolayer.

Study Results

As a result of the study, particles with sizes from 2 $\mu$m to 15 $\mu$m, each having a shape close to spherical, were found on the surfaces of the filters with washings from fragments (items 1 and 2) and swabs (item 15). The chemical basis of the particles is aluminum oxide with impurities of magnesium, silicon, calcium, and iron. The formation of spherical or near-spherical aluminum oxide particles occurs during the combustion or explosion of aluminum-containing explosives or pyrotechnic compositions. The presence of these particles on the filters allows for the conclusion that aluminum was most likely part of the explosive charge.

Conclusions from Physicochemical Studies

Based on the physicochemical studies conducted, the following conclusions can be drawn.

• As an explosive charge, either a composite explosive was used, which included TNT, hexogen, and, most likely, aluminum, or, in addition, ammonium nitrate or a combination of the above substances and explosives based on them could have been included.

It is not possible to establish the specific brand of the exploded explosive by trace amounts. For this reason, it is not possible to determine the area of application of the above-mentioned composite explosive or the explosives that were part of the combined charge.