A Desorption Electrospray Ionization Mass Spectrometry Study of Aging Products of Diphenylamine Stabilizer in Double‐Base Propellants

Abstract

Double‐base propellants consisting of nitrocellulose, nitroglycerin and stabilizer undergo chemical and physical changes upon aging, leading to changes in ballistic power and presenting explosive hazards. During aging, PTFE seals of the glass ampoules used in the aging studies undergo a yellow discoloration. This report studies the discoloration of the liners using desorption electrospray ionization (DESI), a gentle surface analysis technique based on electrospray ionization. The color bodies in the PTFE liners were identified by DESI together with tandem mass spectrometry to be the nitrated derivatives of the diphenylamine stabilizer: dinitro‐, trinitro‐, and tetranitrodiphenylamine. While increased nitration decreases vapor pressure of the DPA species, an increase in solubility in the PTFE liners occurs. This may account for these species not previously being observed during early aging studies as they are preferentially absorbed into the liners, which were not extracted prior to high performance liquid‐ chromatography analysis.

Desorption Electrospray Tandem MS (DESI‐MSMS) Analysis of Methyl Centralite and Ethyl Centralite as Gunshot Residues on Skin and Other Surfaces

“…The tandem MS based technique can supply more characteristic information than other methods, such as chemical visualization and SEM ⁄ EDX method. It is worthy of note that in a previous study on the aging of double-base propellants, DPA and its nitration products could be directly analyzed on solid surfaces (24), which means that all types of stabilizers in smokeless powder could be detected as organic GSRs in firearm-related events. Considering that previous works have proved that DESI-MS is high throughput (25), possible to image biological tissues (20), possible to detect explosives on human skin (26) and successful to couple a portable mass spectrometer (21), DESI-MSMS could be broadly applied in forensic science.…”

Screening of gunshot residues using desorption electrospray ionisation–mass spectrometry (DESI–MS)

“…Recently, ambient ionisation techniques such as desorption electrospray ionisation coupled to mass spectrometry (DESI-MS) have attracted increasing interest for the analysis of organic compounds (including some of those present in OGSR). A fundamental advantage of DESI-MS is the minimal specimen preparation requirements, the possibility to analyse minute samples in their native state and its ability for the analysis of surface deposits [3,[13][14][15][16][17].…”

Secondary electrospray ionization (SESI) of ambient vapors for explosive detection at concentrations below parts per trillion

“…With the advent of electrospray ionization (ESI) [16], API-MS shifted radically from a small effort in the area of volatile analysis to a vast enterprise in the analysis of involatile biological species, leading to drastic increases in API-MS sensitivity. Traditional LC-MS approaches [17,18] as well as new ionization approaches such as DESI [19,20] and DART [21] have been used for explosive analysis from the condensed phase. But the shift from gas to condensed phase analysis in the study of explosives has been maintained, with the notable exception of the early work by Fenn and his students, who had noted the remarkable ability of an electrospray cloud to produce ions from ambient vapors present in the laboratory at very small concentrations [22,23].…”