Rapid identification and desorption mechanisms of nitrogen-based explosives by ambient micro-fabricated glow discharge plasma desorption/ionization (MFGDP) mass spectrometry

• Published in: Talanta (Oxford) 2017-05, Vol.167, p.75-85
• Main Authors: Tian, CaiYan, Yin, JinWei, Zhao, ZhongJun, Zhang, Yinchenxi, Duan, YiXiang
• Format: Article
• Language: English
• Subjects: Desorption ionization; Desorption mechanisms; Explosives; Negative ion mode
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2017.02.011

A novel technique of micro-fabricated glow discharge plasma desorption/ionization mass spectrometry was investigated for the first time in negative ion mode in this study. Negative ion micro-fabricated glow discharge plasma desorption/ionization mass spectrometry (NI-MFGDP-MS) was successfully applied to identify trace explosives in open air. Six explosives and explosives-related compounds were directly analyzed in seconds with this ion source. The ions of [M-H]- were predominant for 2-methyl-1,3,5-trinitrobenzene (trinitrotoluene, TNT) and 2,4,6-trinitrophenol (picric acid), and [M+NO3]- were dominant ions for 1,3,5-trinitro-perhydro-1,3,5-triazine (cyclonite, RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (octogen, HMX), 1,2,3-trinitroxypropane (nitroglycerin, NG), and pentaerythritol tetranitrate (PETN). The limits of detection (LOD) were from 87.5pgmm−2 to 0.4 fg mm−2 and the relative standard deviation (RSD) ranged between 5.8% and 16.8% for the explosives involved in this study. The reliability of NI-MFGDP-MS was characterized by the analysis of a picric acid-RDX-PETN mixture and a mixture of RDX-pond water. NI-MFGDP-MS and ESI-MS were compared with these explosives and along with collision induced dissociation (CID) experiments. The results showed that electron capture, proton abstraction reaction, nucleophilic attack, ion–molecule attachment, decomposition and anion attachment took place during the NI-MFGDP-MS measurement. These findings provide a guideline and a supplement to the chemical libraries for rapid and accurate detection of explosives. The method shows great potential for fast, in situ, on-line and high throughput detection of explosives in the field of antiterrorism. In consider of great advantages for in situ, on-line, high throughput detection and fast identification of explosives, micro-fabricated glow discharge plasma desorption/ionization mass spectrometry in negative ion mode (NI-MFGDP-MS) was used to identify explosives in open air. The capability and the reliability of fast identification of explosives at atmospheric pressure have been successfully demonstrated with NI-MFGDP-MS and the method constructed in this paper has a good performance on quantitative analysis. The mechanisms of desorption of explosives in this system were also explored to identify fast and accurately. The results provide a guideline and a supplement to chemical libraries for the rapid and accurate identification of explosives in the field of antite