LC-MS/MS monitoring for explosives residues and OGSR with diverse ionization temperatures in soil & hands: 30 minutes for extraction + elution

A fast LC-APCI-MS/MS screening/confirmation method was developed and validated for trace analyses of 18 analytes which are explosives and organic gun shot residues including the challenging ones with diverse ionization conditions, in soil and on hands. (+) and (−) ionization modes were used after a single-step, low-volume solvent extraction procedure developed using methanol. Tape-lifting, stub, alcohol wipes, cotton bud were compared for collecting the residues from hands of a shooter. Tape-lifting and stub gave the highest recoveries and tape-lifting was chosen. Gradient elution system using ammonium chloride:methanol was developed. Whole procedure lasted approximately 30 min, was validated in both matrices, applied to real samples as post-blast residues, smokeless powder and the hands of a shooter, after shooting. Most of the recoveries were >80% and since all the precisions were <15%, quantitation was possible for all. Limit of Detection (LOD) and Limit of Quantification (LOQ) values were: 0.2–54.1 and 0.3–190.0 ngg−1 in soil, and 0.2–132.3 and 1.1–355.0 ngg−1 in tape-lift.

Methods of Reducing the Front Performance Flame at the Underground Mines Works

The aim of the study was to develop methods to reduce the penetration ability of the flame front and red-hot striking elements that propagate in the confined space of mines. In the article is considered a method for localizing explosions of a methane-dust mixture in coal mines, by creating an aqueous barrier (increased density) in the propagation path of the flame front and incandescent particles, using a high-energy pyrotechnic composition based on nanoaluminum. The optimal pyrotechnic composition contents of ammonium nitrate - 50%, smokeless powder - 45%, magnesium - 3% and nanoaluminum - 2%. This composition punched the target to a depth of 6.5 mm with a barrier thickness of 50 mm. Water cannon with a nozzle with a diameter of 80mm, allows to localize the spread of the flame front.