Mass Spectrometry’s Important Role in Identifying Explosives in the Environment
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Professor Stanislaw Popiel, Associate Professor of Chemistry at the Military University of Technology, Warsaw, Poland.
Explosives, especially when not contained or disposed of correctly, pose a significant hazard to humans, wildlife and the ecosystem. Having the tools to be able to identify their presence and state are therefore key to combating the issue. We spoke to Stanislaw Popiel about the game-changing role that mass spectrometry is playing in the process and some of the challenges that still lie ahead.
Q: Could you tell us a bit about the role and importance of mass spectrometry in explosive screening?
A: Explosives screening is very important in a number of situations including terrorism attacks, environmental monitoring (training grounds, factories, ground waters etc.) and dumped munitions. Mass spectrometry gives us a powerful tool for identification and quantification of explosives, vital in forensic analysis.
As well as the explosives themselves, their degradation products can also be detected, which may indicate their use. Tandem mass spectrometry allows us to reduce background signal from the sample matrix and reduce the limit of detection and quantification.
Q: How do the analyses made possible through the application of mass spectrometry compare to previously available methods of detection?
A: Mass spectrometry in combination with gas chromatography and especially liquid chromatography can be used in a very wide research spectrum related to explosives. In comparison to other techniques, mass spectrometry is advantageous because with one detector we can do both qualitative and quantitative analysis of explosives and their degradation products. Also, mass spectrometry, especially high-resolution mass spectrometry, enables us to monitor the degradation and metabolization path of explosives, and identify unknown compounds.
We believe that our work on the development and validation of methods for analysis of all explosives and their degradation products will allow for their practical use in environmental monitoring and forensic science. In addition, the possibility of substance identification gives us the opportunity for more complex analyses of environmental or forensic samples.
Q: What are the biggest challenges that are still to be overcome and how might they be addressed?
A: The biggest challenge is to develop and validate sensitive methods for the detection of explosives and their degradation products in sea water and sediment samples, as large amounts of conventional and chemical munitions are dumped in the oceans and seas. Both chemical warfare agents and explosives undergo very complex transformations under the influence of the marine environment. As a result, after a long time, a lot of substances significantly differ from the starting substances which were dumped in the marine environment. In addition, substances appearing as a result of chemical or biochemical transformation are on the one hand in very different concentrations, and on the other hand, often have similar properties and therefore it is difficult to distinguish, identify and quantify them. Sea water and sediments are very complex matrices and extraction of analytes with one solvent yielding good recovery is difficult to achieve.
A related significant aspect is to determine the influence of explosives and their degradation products on the marine environment. In both cases, mass spectrometry is a powerful tool and importantly does not limit identification to known metabolites and degradation products. This information is crucial for determining the toxicity of explosives and allows us to trace the path of their metabolism.
Q: Can you tell us about an occasion where this technology has been successfully applied to combat crime?
A: Our laboratory have applied mass spectrometry for the identification and quantification of explosives and their degradations products in sediment samples and actual explosives fished out of the Baltic Sea. These have included trinitrotoluene (TNT) and (cyclotrimethylenetrinitramine) RDX.
Mass spectrometry has crime fighting applications beyond explosives including the analysis of drugs1, 2, herbal medicines3 and dietary supplements3. These applications are very important in forensic analysis because their results are used as evidence in criminal proceedings. Mass spectrometry gives us new possibilities to search for traces substances that can be used as evidence.
1. P. Lebel, J. Gagnon, A. Furtos, K. C. Waldron, A rapid, quantitative liquid chromatography-mass spectrometry screening method for 71 active and 11 natural erectile dysfunction ingredients present in potentially adulterated or counterfeit products, J. Chromatogr. A, 1343 (2014) 134-151.
2. J. Kim, H. Yum, M. Jang, I. Shin, W. Yang, S. Baeck, J. H. Suh, S. Lee, S. B. Han, A comprehensive and sensitive method for hair analysis in drug-facilitated crimes and incorporation of zolazepam and tiletamine into hair after a single exposure, Anal. Bioanal. Chem., 408 (2016) 251–263.
3. F. Shi, C. Guo, L. Gong, J. Li, P. Dong, J. Zhang, P. Cui, S. Jiang, Y. Zhao, Su Zengd, Application of a high-resolution benchtop quadrupole-Orbitrap mass pectrometry for the rapid screening, confirmation and quantification of illegal adulterated phosphodiesterase-5 inhibitors in herbal medicines and dietary supplements, J. Chromatogr. A, 1344 (2014) 91-98.
Professor Stanislaw Popiel was speaking to Dr Karen Steward, Science Writer for Technology Networks.
Dr. Stanislaw Popiel is an Associate Professor of Chemistry at the Military University of Technology in Warsaw, Poland. Prof. Popiel has over 30 years of experience in analytical chemistry, especially in analysis of dangerous substances, such as chemical warfare agents, explosives and their degradation products. His main task is the development and validation of analytical methods based on both gas and liquid chromatography especially in combination with mass and tandem mass spectrometry. In his lab, Prof. Popiel has a number of analytical instrumentations with several Master’s & PhD students. He holds numerous publications in his field and notable awards.