Explosives detectionMass spectrometry for detection of trace quantities of explosives

The detection of trace quantities of explosives is critical to defending civilian populations from terrorist attacks. Freneil Jariwala, graduate student at Stevens Institute of Technology, and Dr. Athula B. Attygalle of the Department of Chemistry, Chemical Biology & Biomedical Engineering have developed a method of modifying a commercial electrospray ionization source for ambient detection of explosives on surfaces.

A Stevens Institute of Technology release reports that at the American Society of Mass Spectrometry (ASMS) regional meeting on 17 April 2012, Dr. Ron Kong, chair of the North Jersey Section of the American Chemical Society, awarded Freneil a grant to present the results of his research at the 60th ASMS Conference on Mass Spectrometry and Allied Topics, to be held 20-24 May in Vancouver, B.C., Canada. Freneil is the only graduate student presenter who was awarded this privilege.

“The ASMS travel grant is well-merited recognition of the outstanding effort, talent and creativity that Freneil has demonstrated with this research,” says Dr. Michael Bruno, dean of the Charles V. Schaefer Jr. School of Engineering and Science. “This has substantial implications for homeland security, and it shows what extraordinary opportunities for impactful research are available to our students.”

In order to survey and protect high-risk areas, police and security personnel often rely on the heightened olfactory sense of dogs to detect trace quantities of volatiles, or chemicals with a tendency to vaporize, released by explosives. This presents a challenge because most explosives have very low vapor pressures. Alternatively, instrumental methods for explosives detection exist but require extensive sample preparation and analysis time. Mass spectrometry is the method of choice because of its extraordinary sensitivity, but even then, some mass spectrometry methods require extensive sample preparation.

Freneil and Dr. Attygalle have responded to this problem by developing a sample introduction system for mass spectrometry based on helium plasma. They report a simple modification to a commercially available electrospray ionization (ESI) source in order to sense very small traces of explosives in a non-invasive manner that does not require extensive sample preparation. In the course of their research, Freneil and Dr. Attygalle detected explosives (DNT, TNT, DNAN, RDX, HMX, CL-20, and PETN) which were deposited (~10 ng) on various surfaces, such as glass, steel, plastic, paper, cloth, and human skin.

“Of all the research students I have supervised during my career, I would place Freneil in the top two percent because of his tremendous research achievements,” says Dr. Attygalle. “This is an outstanding discovery with the potential to be applied widely in the near future.”

The release notes that Freneil’s research marks the third peer-reviewed publication to his credit. His first, titled “Ortho Effect in Electron Ionization Mass Spectrometry of N-Acylanilines Bearing a Proximal Halo Substituent,” appeared in the Journal of the American Mass Spectrometry Society in 2008. Recently, one of his major discoveries on the “Formation of the bisulfite anion (HSO3– , m/z 81) upon collision-induced dissociation of anions derived from organic sulfonic acids” was accepted for publication in the Journal of Mass Spectrometry. One of its peer reviewers commented, “The study represents a nice example of fundamental gas phase ion chemistry. Derivatives of sulfonic acids are an important class of organic compounds. The study is interesting and has practical utilities.”

“Stevens and ASMS share in their respective missions the critical responsibility of early identification and nurture of students with exceptional talent in order that they might achieve their full potential and establish bright careers,” says Dr. Attygalle. “I am confident that Freneil will become a prominent mass spectrometrist, either in academia or in the pharmaceutical industry in the near future.”