Analysis of Sample Components

Visual Examination

• Selected objects were examined visually using an MZ12 microscope from Leica (Germany) at various magnifications and lighting.
• As a result of the examination of microparticles and particles, no substances resembling explosives, gunpowder, pyrotechnic compositions, or their individual components were found by appearance.

Chemical Extraction and Preparation

• Methanol and acetone washes were taken from the objects.
• The washes were filtered through ashless "white ribbon" filters and, after evaporation in a helium stream to a volume of 1 ml, were divided in half.
  • One part, intended for examination by HPTLC and GC-MS methods, was evaporated to a volume of 0.2 - 0.3 ml.
  • The other, intended for analysis by the IC [Ion Chromatography] method, was dried until the solvent was completely removed and filled with bidistilled water in a volume of 1 ml for each wash.
• The remaining filters were dried and preserved for further research.

Detection of Trace Components

• To detect trace amounts of high explosives and organic components of smokeless powders (diphenylamine and centralites), acetone and methanol washes were examined using HPTLC and GC-MS methods.

HPTLC Study

The HPTLC study was conducted using a complex of chromatographic equipment from Camag (Switzerland) under the following conditions:
* "HPTLC Silica gel 60 F 254" plate from Merck (Germany);
* Applied sample volume - 40 μl;
* Eluent - benzene;
* Eluent rise height from the start line - 50 mm;
* Control samples - acetone solution of the most well-known high explosives (TNT, hexogen [RDX], octogen [HMX], PETN, nitroglycerin, tetryl, and picric acid), chloromethylene extracts of smokeless powders of various brands.

The presence of explosives and smokeless powder components was determined by:
* The correspondence of the relative mobility values of the substance spots on the chromatograms of the studied and control solutions.
* Reaction to the effects of developing reagents:
* A solution of diphenylamine in an alcohol-acetone mixture followed by UV irradiation at a wavelength of 366 nm.
* A solution of ethylenediamine in acetone.
* A 5% solution of potassium bichromate in a mixture of sulfuric and acetic acids.

GC-MS Study

The GC-MS study was conducted on a GCQ spectrometer from Finnigan MAT (USA).
* Separation of substances was carried out in a helium stream at a speed of 60 cm/s on a DB-1 column from J&W Scientific (USA) with a diameter of 0.25 mm, a phase layer thickness of 0.25 μm, and a length of 15 m.
* The volume of the injected sample was 1 μl.
* Injector temperature - 200 °C.
* Splitless injector mode.
* Column temperature: isothermal at 70 °C for 1 min, then programmed heating at a rate of 25 °C/min to [?].
* Ion source temperature - 150 °C, interface - 250 °C.

Mass spectra of the separated substances were recorded in the chemical ionization mode with methane reagent gas in the range of negative masses...