Stamatios Giannoukos

Membrane Inlet Mass Spectrometry for Homeland Security and Forensic Applications

AbstractA man-portable membrane inlet mass spectrometer has been built and tested to detect and monitor characteristic odors emitted from the human body and also from threat substances. In each case, a heated membrane sampling probe was used. During human scent monitoring experiments, data were obtained for inorganic gases and volatile organic compounds emitted from human breath and sweat in a confined space. Volatile emissions were detected from the human body at low ppb concentrations. Experiments with compounds associated with narcotics, explosives, and chemical warfare agents were conducted for a range of membrane types. Test compounds included methyl benzoate (odor signature of cocaine), piperidine (precursor in clandestine phencyclidine manufacturing processes), 2-nitrotoluene (breakdown product of TNT), cyclohexanone (volatile signature of plastic explosives), dimethyl methylphosphonate (used in sarin and soman nerve agent production), and 2-chloroethyl ethyl sulfide (simulant compound for sulfur mustard gas). Gas phase calibration experiments were performed allowing sub-ppb LOD to be established. The results showed excellent linearity versus concentration and rapid membrane response times. Graphical Abstractᅟ

Monitoring of human chemical signatures using membrane inlet mass spectrometry.

This work is an attempt to assist border security crackdown on illegal human immigration, by providing essential results on human chemical signatures. Data was obtained using a portable quadrupole mass spectrometer coupled with a membrane probe for volunteers of both genders and under different conditions in a container simulator. During experiments, participants were asked to follow various protocols while volatile organic compounds emitted from their breath, sweat, skin, and other biological excretes were continuously being monitored. Experimental setups using different membrane materials (both hydrophilic and hydrophobic) including heating of the sampling probe and sampling flow rates were examined. From our measurements, significant information was obtained for NH3, CO2, water, and volatile organic compounds levels, illustrating a human chemical profile and indicating human presence in a confined space.

Dynamic vapor generator that simulates transient odor emissions of victims entrapped in the voids of collapsed buildings.

The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system. A series of experiments were conducted for evaluating the simulators performance, defining types and weights of different factors, and proposing further optimization of the device. The developed device enabled the production of stable and transient odor profiles in a controllable and reproducible way (relative standard deviation, RSD < 11%) at ppbv to low ppmv concentrations and allowed emission durations up to 30 min. Moreover, the factors affecting its optimum performance (i.e., evaporation chamber temperature, air flow rate through the mixing chamber, air flow rate through the evaporation chamber, and type of compound) were evaluated through an analysis of variance (ANOVA) tool revealing the next steps toward optimizing the generator. The developed simulator, potentially, can also serve the need for calibrating and evaluating the performance of analytical devices (e.g., gas chromatographers, ion mobility spectrometers, mass spectrometers, sensors, e-noses) in the field. Furthermore, it can contribute in better training of urban search and rescue (USaR) canines.

Analysis of chlorinated hydrocarbons in gas phase using a portable membrane inlet mass spectrometer

A compact portable membrane inlet mass spectrometer (MIMS) has been used for the first time to detect and monitor, both qualitatively and quantitatively, volatile chlorinated hydrocarbons in the gaseous phase. Continuous monitoring of such compounds in the field is of importance due to their wide industrial use and their potential negative impact on public health and the environment. Compounds tested include vinyl chloride, 1,1-dichloroethylene, trichloroethylene and tetrachloroethylene. Gas phase experiments were performed at concentration levels from low ppb to low ppm. The results obtained showed very good linearity within the examined concentration range, ppb limits of detection and fast response (rise and fall) times. Mixture effects are also presented. The MIMS system was also investigated under periodic and dynamic experimental conditions and demonstrated stable and repeatable measurements.

Molecular Communication over Gas Stream Channels using Portable Mass Spectrometry.

AbstractThe synthetic generation/coding and transmission of olfactory information over a gas stream or an odor network is a new and unexplored field. Application areas vary from the entertainment or advertisement industry to security and telemedicine. However, current technological limitations frustrate the accurate reproduction of decoded and transmitted olfactory data. This study describes the development, testing, and characterization of a novel odor emitter (OE) that is used to investigate the generation-encoding of gaseous standards with odorous characteristics with a regulatable way, for scent transmission purposes. The calibration and the responses of a developed OE were examined using a portable quadrupole mass spectrometer (MS). Experiments were undertaken for a range of volatile organic compounds (VOCs) at different temperatures and flow rates. Individual compounds and mixtures were tested to investigate periodic and dynamic transmission characteristics within two different size tubular containers for distances up to 3 m. Olfactory information transmission is demonstrated using MS as the main molecular sensor for odor detection and monitoring and for the first time spatial encryption of olfactory information is shown. Graphical Abstractᅟ

Advances in chemical sensing technologies for VOCs in breath for security/threat assessment, illicit drug detection, and human trafficking activity

On-site chemical sensing of compounds associated with security and terrorist attacks is of worldwide interest. Other related bio-monitoring topics include identification of individuals posing a threat from illicit drugs, explosive manufacturing, as well as searching for victims of human trafficking and collapsed buildings. The current status of field analytical technologies is directed towards the detection and identification of vapours and volatile organic compounds (VOCs). Some VOCs are associated with exhaled breath, where research is moving from individual breath testing (volatilome) to cell breath (microbiome) and most recently to crowd breath metabolites (exposome). In this paper, an overview of field-deployable chemical screening technologies (both stand-alone and those with portable characteristics) is given with application to early detection and monitoring of human exposome in security operations. On-site systems employed in exhaled breath analysis, i.e. mass spectrometry (MS), optical spectroscopy and chemical sensors are reviewed. Categories of VOCs of interest include (a) VOCs in human breath associated with exposure to threat compounds, and (b) VOCs characteristic of, and associated with, human body odour (e.g. breath, sweat). The latter are relevant to human trafficking scenarios. New technological approaches in miniaturised detection and screening systems are also presented (e.g. non-scanning digital light processing linear ion trap MS (DLP-LIT-MS), nanoparticles, mid-infrared photo-acoustic spectroscopy and hyphenated technologies). Finally, the outlook for rapid and precise, real-time field detection of threat traces in exhaled breath is revealed and discussed.

Portable mass spectrometry for the direct analysis and quantification of volatile halogenated hydrocarbons in the gas phase

Field chemical analysis (FCA) of volatile halogenated hydrocarbons is a highly debated topic of widespread interest due to the significant negative impact of these compounds on public health, on ecosystems and in the environment (e.g. destruction of stratospheric ozone). This article reports, for the first time, the use of a unique, lightweight (11 kg), man-portable membrane inlet mass spectrometer (MIMS) in the qualitative determination (for both detection and screening) and quantitative analysis of organohalogen chemical analytes in the gaseous phase. Representative compounds examined include: (a) volatile organochlorine compounds (e.g. trichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,1,2-tetrachloroethane), (b) volatile organobromine and chlorobromocarbon compounds (e.g. bromomethane, dibromomethane, chlorobromomethane, bromodichloromethane), and (c) volatile chlorofluorocarbon and organoiodine compounds (e.g. chlorodifluoromethane, trichlorofluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, methyl iodide). Gas phase experiments were undertaken at concentration levels from low ppb to low ppm. The results obtained exhibited excellent linearity within the concentration range examined, high sensitivity (limit of detection < 10 ppb), good repeatability (relative standard deviation, RSD < 5%) and membrane response times in real time (analysis within few seconds). Chemical investigations of mixture effects are also presented. Our method was successfully validated in laboratory based experiments within a test chamber.

Asymmetrical inter-symbol interference in macro-scale molecular communications

Molecular communication (MC) is new method of information transmission whereby information is carried by chemical signals instead of electromagnetic (EM) waves. This shift to a new type of information carrier makes MC a viable option in circumstances where EM communication might prove inefficient, e.g., in underwater and underground communications or for in-body and biological applications. To date, almost all MC systems that have been proposed have focused on nano- and micro-scale communications, however recent research has sought to implement MC at macro-scales. A major problem of MC is the inter-symbol interference (ISI) caused by residual chemicals leftover from a previous transmission which can cause incorrect decoding of the signal. This paper reports an experimental study conducted on transmitting MC at the macro-scale. A mass spectrometer (MS) was used as the detector and an algorithm was designed to help mitigate the memory effect of the channel. It is shown that by using the algorithm, communication in the macro-scale is made more practical and feasible.