Applications of Direct Injection Soft Chemical Ionisation-Mass Spectrometry for the Detection of Pre-blast Smokeless Powder Organic Additives

Abstract

Analysis of smokeless powders is of interest from forensics and security perspectives. This article reports the detection of smokeless powder organic additives (in their pre-detonation condition), namely the stabiliser diphenylamine and its derivatives 2-nitrodiphenylamine and 4nitrodiphenylamine, and the additives (used both as stabilisers and plasticisers) methyl centralite and ethyl centralite, by means of swab sampling followed by thermal desorption and direct injection soft chemical ionisation-mass spectrometry. Investigations on the product ions resulting from the reactions of the reagent ions H 3 O + and O 2 + with additives as a function of reduced electric field are reported. The method was comprehensively evaluated in terms of linearity, sensitivity and precision. For H 3 O + , the limits of detection (LoD) are in the range of 41-88 pg of additive, for which the accuracy varied between 1.5 and 3.2%, precision varied between 3.7 and 7.3% and linearity showed R 2 ≥ 0.9991. For O 2 + , LoD are in the range of 72 to 1.4 ng, with an accuracy of between 2.8 and 4.9% and a precision between 4.5 and 8.6% and R 2 ≥ 0.9914. The validated methodology was applied to the analysis of commercial pre-blast gun powders from different manufacturers.Research Highlights • Use of direct injection soft chemical ionisation-mass spectrometry for smokeless powder organic additive analysis

Armed with the Facts: A Method for the Analysis of Smokeless Powders by Ambient Mass Spectrometry

“…NNODPA has been a noticeable omission from other studies on the ambient ionization of forensic samples, for example, Black et al and Gonzalez-Mendez and Mayhew. , Lennert and Bridge did report detection of the diphenylamidogen radical cation fragment by DART-MS, but when applying principal components analysis they found this peak had little impact for their purpose of classifying SPs within the sample population . In contrast to results presented by many authors but in agreement with Li et al, simultaneous detection of both the NNODPA protonated molecular ion (calcd m/z 199.0866, meas m / z 199.0859, n = 5, Δppm −3.72) and the more commonly described diphenylamidogen radical cation (calcd m/z 169.0886, meas m / z 169.0890, n = 5, Δppm +2.25) were achieved in the current study.…”

Vapor Signatures of Double-Base Smokeless Powders and Gunshot Residues for Supporting Canine Odor Imprinting

“…This study used a triple-quadrupole mass spectrometer with a custom ionization source to directly measure vapor emanation from the sample . The system in this study differs from many past MS measurements by (1) not requiring vapor sampling like SPME-GC/MS, ,,,, (2) not requiring liquid extraction of the solid sample, , (3) not heating the sample, and (4) not requiring a sample desorption step like thermal desorption or desorption electrospray ionization (DESI). All measurements herein focused on naturally emanating vapor and were conducted in real-time under ambient conditions (∼20 °C).…”

Proton transfer reaction mass spectrometry investigations of phthalate esters via direct headspace sampling

“…25 PTR-MS has found use in a broad range of analytical fields and applications, spanning from environmental analysis, to food science, atmospheric chemistry, health science, and homeland security. 24,25,26,27,[28][29][30][31][32][33][34][35][36][37] In a previous study by González-Méndez et al, dealing with PTR-MS and smokeless powder, there was an indication of phthalate compounds being present in the powders. 36 In a continuation of that study we present here with CID being enhanced with increasing reduced electric field.…”