1
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Corbally MA, Freye CE. Development of a Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry Methodology for BDNPA/F. ACS OMEGA 2023; 8:30330-30334. [PMID: 37636911 PMCID: PMC10448686 DOI: 10.1021/acsomega.3c03382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/28/2023] [Indexed: 08/29/2023]
Abstract
Analysis of thermally labile compounds such as bis(2,2-dinitropropyl) acetal/formal (BDNPA/F), an energetic plasticizer, is usually performed via liquid chromatography (LC) as opposed to gas chromatography (GC) due to thermal decomposition in the inlet or the analytical column. While LC is a powerful technique, the analysis of volatile and semivolatile compounds is best suited to GC. Herein, a method was developed for a gas chromatograph coupled to high-resolution mass spectrometer (GC-HRMS), utilizing a programmable temperature vaporizer (PTV) inlet. A subset of the native compounds and several produced by the thermal decomposition of BDNPA/F in the inlet were evaluated by using multiple PTV inlet parameters to determine the optimal ramp rate and final temperature of the inlet (60 °C/min from 60 to 325 °C). The optimized GC-HRMS method nearly reduced all thermal decomposition, allowing for an excellent separation to be obtained. Furthermore, multiple ionization methods, including electron impact (EI), negative chemical ionization (NCI), and positive chemical ionization (PCI), were used to explore the many chemical differences between the BDNPA/F samples. A preliminary investigation of the benefits of using GC-HRMS to evaluate the chemical differences between unaged and aged BDNPA/F samples for unique insight was evaluated.
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Affiliation(s)
- Michelle A. Corbally
- Q-5, High Explosives Science
and Technology, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Chris E. Freye
- Q-5, High Explosives Science
and Technology, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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2
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Fulton AC, Vaughan SR, DeGreeff LE. Non-contact Detection of Fentanyl by a Field-portable Ion Mobility Spectrometer. Drug Test Anal 2022; 14:1451-1459. [PMID: 35419977 DOI: 10.1002/dta.3272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/07/2022] [Accepted: 04/07/2022] [Indexed: 11/10/2022]
Abstract
Rapid on-site detection of fentanyl is paramount for the safety of law enforcement and other first responders. Due to the opioid epidemic, death by overdose is at an all-time high with fentanyl adulteration as the main assailant. Providing a user-friendly method for the presumptive detection of fentanyl will increase safety for first responders. Ion mobility spectrometry (IMS) provides a quick, affordable, and accurate method for detecting fentanyl. Currently, most methods for detecting fentanyl requires manipulation or handling of the highly potent substance. A recent comparative analysis study on the headspace of fentanyl determined N-phenylpropanamide (NPPA) a target analyte for fentanyl enabling vapor detection. Here, we demonstrate the development of a handheld IMS method for vapor detection of the target analyte for fentanyl. An alarm was programmed into the handheld IMS device for the detection of NPPA. The system was able to accurately detect NPPA in samples of reference-grade fentanyl and diluted reference-grade fentanyl, as well as 3.67 mg of fentanyl from samples confiscated from the U.S. border. Common adulterants and over-the-counter drugs were tested and resulted in a false alarm rate of 0 for substances sampled. The limit of detection was determined to be as low as 5 ng of NPPA. Overall, the development of this user-friendly, non-contact method has considerable promise for near real-time non-contact detection of fentanyl increasing safety of first responders.
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Affiliation(s)
- Ashley C Fulton
- American Society for Engineering Education post-doctoral fellow at the Naval Research Laboratory, Washington, DC, United States
| | - Stephanie R Vaughan
- National Research Council post-doctoral fellow at the Naval Research Laboratory, Washington, DC, United States
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3
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Zhang J, Fahrenthold EP. Spin Current Sensing for Selective Detection of Explosive Molecules. ACS APPLIED MATERIALS & INTERFACES 2022; 14:4469-4478. [PMID: 35014250 DOI: 10.1021/acsami.1c24013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Spin current based sensing methods offer a new approach to the development of selective detection devices for explosive molecules. Employing a combination of bias voltages and transverse electric fields to vary the chemiresistive properties of a zigzag graphene nanoribbon, dual-input dual-output sensors of this kind offer major advantages: tuning the electrical properties of a single nanoribbon is equivalent to deploying a sensor array, and measuring two outputs (spin-up and spin-down currents, total current and spin current difference, etc.) offers improved selectivity. Ab initio modeling suggests that the magnetic properties of the analyte, charge transfer effects, current transmission pathways, and analyte molecule size all influence sensor signatures. Analysis of the sensing cause-effect physics relies upon the calculation of energy averaged bond currents, which visualize the global spin current transport. Principal component analysis of the proposed sensing scheme suggests that it can distinguish between common background gases, nitroaromatic explosives, and nitramine explosives and will offer far better selectivity than carbon nanotube based explosive sensing devices.
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Affiliation(s)
- Jie Zhang
- Department of Mechanical Engineering, University of Texas, Austin, Texas 78712, United States
| | - Eric P Fahrenthold
- Department of Mechanical Engineering, University of Texas, Austin, Texas 78712, United States
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4
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Morrison KA, Denis EH, Nims MK, Broderick AM, Fausey RC, Rose HJ, Gongwer PE, Ewing RG. Vapor Pressures of RDX and HMX Explosives Measured at and Near Room Temperature: 1,3,5-Trinitro-1,3,5-triazinane and 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane. J Phys Chem A 2021; 125:1279-1288. [DOI: 10.1021/acs.jpca.0c10409] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kelsey A. Morrison
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box
999, MSIN P7-50, Richland, Washington 99352, United States
| | - Elizabeth H. Denis
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box
999, MSIN P7-50, Richland, Washington 99352, United States
| | - Megan K. Nims
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box
999, MSIN P7-50, Richland, Washington 99352, United States
| | - Alicia M. Broderick
- U.S. Department of Homeland Security Science and Technology Directorate’s Transportation Security Laboratory, Atlantic City, New Jersey 08405, United States
| | - Rachel C. Fausey
- U.S. Department of Homeland Security Science and Technology Directorate’s Transportation Security Laboratory, Atlantic City, New Jersey 08405, United States
| | - Harry J. Rose
- U.S. Department of Homeland Security Science and Technology Directorate’s Transportation Security Laboratory, Atlantic City, New Jersey 08405, United States
| | - Polly E. Gongwer
- U.S. Department of Homeland Security Science and Technology Directorate’s Transportation Security Laboratory, Atlantic City, New Jersey 08405, United States
| | - Robert G. Ewing
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box
999, MSIN P7-50, Richland, Washington 99352, United States
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5
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Mullen M, Katilie C, Collins GE, Giordano BC. Empirical determination of explosive vapor transport efficiencies. Analyst 2021; 146:5124-5134. [PMID: 34269775 DOI: 10.1039/d1an00984b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transport efficiency of 2,4-dinitrotoluene (2,4-DNT), 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazinane (RDX) trace vapors through tubing materials that commonly constitute vapor handling infrastructures have been determined for a variety of tubing dimensions and sampling conditions. Using a programmable temperature vaporization inlet coupled with a gas chromatography mass spectrometer (PTV-GC-MS), the explosive vapors were quantified both with and without a length of tubing of a specific material in the sampling flow path. At vapor temperatures of 30 °C and 66 °C, minimal attenuations were observed for 2,4-DNT and TNT vapor concentrations when the tubing material was in-line with the sampling flow path, indicating that the transport is largely unaffected by interactions with the surface of the tubing materials. In contrast, RDX vapors showed large attenuations as a function of both sampling conditions and tubing materials/dimensions. For those experiments where attenuated RDX vapor transport was observed, the mass sequestered by interactions between the flowing vapor and the internal tubing surface was determined to be in the range of tens to hundreds of picograms. Of all the materials examined for RDX transport, fluorinated ethylene propylene (FEP) tubing resulted in the least amount of mass loss to surface interactions, with vapor transport efficiencies (VTEs) between 95-100%. However, for some materials, the combination of tubing dimensions and sampling conditions resulted in no RDX transport, even after sampling more than 250.0 L of vapor through the tubing.
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Affiliation(s)
- Matthew Mullen
- NRC Post-Doctoral Fellow, U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, D.C. 20375, USA
| | | | - Greg E Collins
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, D.C. 20375, USA.
| | - Braden C Giordano
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, D.C. 20375, USA.
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6
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Giordano BC, DeGreeff LE, Malito M, Hammond M, Katilie C, Mullen M, Collins GE, Rose-Pehrsson SL. Trace vapor generator for Explosives and Narcotics (TV-Gen). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:085112. [PMID: 32872913 DOI: 10.1063/1.5142385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
The Trace Vapor Generator for Explosives and Narcotics (TV-Gen) is a portable and compact instrument designed to deliver a continuous source of trace-level vapors and vapor mixtures. It provides a tool to assist in the independent validation and verification of new materials and sensors under development for the vapor detection of explosives and narcotics. The design was conceived for use with a broad range of analytes, detection systems, materials, and sensors and to switch easily between the clean and analyte vapor streams. The TV-Gen system utilizes nebulization of aqueous analyte solutions, an oven to promote efficient transport, and a control box that provides dedicated computer control with logging capabilities. Resultant vapor streams are stable over several hours, with the vapor concentration controlled by a combination of aqueous analyte solution concentration, liquid flow rate through the nebulizer, and volume flow rate of air through the TV-Gen manifold.
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Affiliation(s)
- Braden C Giordano
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375, USA
| | - Lauryn E DeGreeff
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375, USA
| | - Michael Malito
- Nova Research, Inc., 1900 Elkin St., Suite 230, Alexandria, Virginia 22308, USA
| | - Mark Hammond
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375, USA
| | - Christopher Katilie
- Nova Research, Inc., 1900 Elkin St., Suite 230, Alexandria, Virginia 22308, USA
| | - Matthew Mullen
- National Research Council, 500 Fifth St., NW, Washington, DC 20001, USA
| | - Greg E Collins
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375, USA
| | - Susan L Rose-Pehrsson
- Chemistry Division, U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC 20375, USA
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7
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Part per quadrillion quantitation of pentaerythritol tetranitrate vapor using online sampling gas chromatography–mass spectrometry. J Chromatogr A 2019; 1603:407-411. [DOI: 10.1016/j.chroma.2019.05.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 05/14/2019] [Indexed: 11/18/2022]
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8
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Giordano BC, Ratchford DC, Johnson KJ, Pehrsson PE. Silicon nanowire arrays for the preconcentration and separation of trace explosives vapors. J Chromatogr A 2019; 1597:54-62. [DOI: 10.1016/j.chroma.2019.03.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/20/2019] [Accepted: 03/21/2019] [Indexed: 11/27/2022]
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9
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Wang J, Yu R, Tao F, Cui Y, Li T. Determination of Nitroaromatics Using a Double-Layer of Gelatin Nanofibers and a Pyrene-Doped Polystyrene Membrane. ANAL LETT 2018. [DOI: 10.1080/00032719.2018.1455104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Jiemei Wang
- Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Runhui Yu
- Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Furong Tao
- Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Yuezhi Cui
- Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Tianduo Li
- Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
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10
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Mixed Vapor Generation Device for delivery of homemade explosives vapor plumes. Anal Chim Acta 2018; 1040:41-48. [DOI: 10.1016/j.aca.2018.07.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/08/2018] [Accepted: 07/14/2018] [Indexed: 11/22/2022]
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11
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McEneff GL, Murphy B, Webb T, Wood D, Irlam R, Mills J, Green D, Barron LP. Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part A: Materials Optimisation and Integration with Analytical Technologies. Sci Rep 2018; 8:5815. [PMID: 29643465 PMCID: PMC5895691 DOI: 10.1038/s41598-018-24244-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/26/2018] [Indexed: 11/25/2022] Open
Abstract
A new thin-film passive sampler is presented as a low resource dependent and discrete continuous monitoring solution for explosives-related vapours. Using 15 mid-high vapour pressure explosives-related compounds as probes, combinations of four thermally stable substrates and six film-based sorbents were evaluated. Meta-aramid and phenylene oxide-based materials showed the best recoveries from small voids (~70%). Analysis was performed using liquid chromatography-high resolution accurate mass spectrometry which also enabled tentative identification of new targets from the acquired data. Preliminary uptake kinetics experiments revealed plateau concentrations on the device were reached between 3–5 days. Compounds used in improvised explosive devices, such as triacetone triperoxide, were detected within 1 hour and were stably retained by the sampler for up to 7 days. Sampler performance was consistent for 22 months after manufacture. Lastly, its direct integration with currently in-service explosives screening equipment including ion mobility spectrometry and thermal desorption mass spectrometry is presented. Following exposure to several open environments and targeted interferences, sampler performance was subsequently assessed and potential interferences identified. High-security building and area monitoring for concealed explosives using such cost-effective and discrete passive samplers can add extra assurance to search routines while minimising any additional burden on personnel or everyday site operation.
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Affiliation(s)
- Gillian L McEneff
- King's Forensics, School of Population Health & Environmental Sciences, Faculty of Life Sciences & Medicine, King's College London, London, SE1 9NH, United Kingdom.
| | - Bronagh Murphy
- King's Forensics, School of Population Health & Environmental Sciences, Faculty of Life Sciences & Medicine, King's College London, London, SE1 9NH, United Kingdom
| | - Tony Webb
- Threat Mitigation Technologies, Metropolitan Police Service, 113 Grove Park, London, SE5 8LE, United Kingdom
| | - Dan Wood
- Threat Mitigation Technologies, Metropolitan Police Service, 113 Grove Park, London, SE5 8LE, United Kingdom
| | - Rachel Irlam
- King's Forensics, School of Population Health & Environmental Sciences, Faculty of Life Sciences & Medicine, King's College London, London, SE1 9NH, United Kingdom
| | - Jim Mills
- Air Monitors Ltd., 2/3 Miller Court, Severn Drive, Tewkesbury, Gloucestershire, GL20 8DN, United Kingdom
| | - David Green
- King's Forensics, School of Population Health & Environmental Sciences, Faculty of Life Sciences & Medicine, King's College London, London, SE1 9NH, United Kingdom
| | - Leon P Barron
- King's Forensics, School of Population Health & Environmental Sciences, Faculty of Life Sciences & Medicine, King's College London, London, SE1 9NH, United Kingdom.
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12
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Shriver-Lake LC, Zabetakis D, Dressick WJ, Stenger DA, Trammell SA. Paper-Based Electrochemical Detection of Chlorate. SENSORS 2018; 18:s18020328. [PMID: 29364153 PMCID: PMC5855869 DOI: 10.3390/s18020328] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/12/2018] [Accepted: 01/19/2018] [Indexed: 11/16/2022]
Abstract
We describe the use of a paper-based probe impregnated with a vanadium-containing polyoxometalate anion, [PMo11VO40]5−, on screen-printed carbon electrodes for the electrochemical determination of chlorate. Cyclic voltammetry (CV) and chronocoulometry were used to characterize the ClO3− response in a pH = 2.5 solution of 100 mM sodium acetate. A linear CV current response was observed between 0.156 and 1.25 mg/mL with a detection limit of 0.083 mg/mL (S/N > 3). This performance was reproducible using [PMo11VO40]5−-impregnated filter paper stored under ambient conditions for as long as 8 months prior to use. At high concentration of chlorate, an additional catalytic cathodic peak was seen in the reverse scan of the CVs, which was digitally simulated using a simple model. For chronocoulometry, the charge measured after 5 min gave a linear response from 0.625 to 2.5 mg/mL with a detection limit of 0.31 mg/mL (S/N > 3). In addition, the slope of charge vs. time also gave a linear response. In this case the linear range was from 0.312 to 2.5 mg/mL with a detection limit of 0.15 mg/mL (S/N > 3). Simple assays were conducted using three types of soil, and recovery measurements reported.
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Affiliation(s)
- Lisa C Shriver-Lake
- U.S. Naval Research Laboratory, Center for Bio/Molecular Science & Engineering (Code 6900), 4555 Overlook Avenue SW, Washington, DC 20375, USA.
| | - Dan Zabetakis
- U.S. Naval Research Laboratory, Center for Bio/Molecular Science & Engineering (Code 6900), 4555 Overlook Avenue SW, Washington, DC 20375, USA.
| | - Walter J Dressick
- U.S. Naval Research Laboratory, Center for Bio/Molecular Science & Engineering (Code 6900), 4555 Overlook Avenue SW, Washington, DC 20375, USA.
| | - David A Stenger
- U.S. Naval Research Laboratory, Center for Bio/Molecular Science & Engineering (Code 6900), 4555 Overlook Avenue SW, Washington, DC 20375, USA.
| | - Scott A Trammell
- U.S. Naval Research Laboratory, Center for Bio/Molecular Science & Engineering (Code 6900), 4555 Overlook Avenue SW, Washington, DC 20375, USA.
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Collins GE, Malito MP, Tamanaha CR, Hammond MH, Giordano BC, Lubrano AL, Field CR, Rogers DA, Jeffries RA, Colton RJ, Rose-Pehrsson SL. Trace explosives sensor testbed (TESTbed). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:034104. [PMID: 28372430 DOI: 10.1063/1.4978963] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation.
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Affiliation(s)
- Greg E Collins
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Michael P Malito
- Nova Research, Inc., 1900 Elkin St., Suite 230, Alexandria, Virginia 22308, USA
| | - Cy R Tamanaha
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Mark H Hammond
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Braden C Giordano
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Adam L Lubrano
- Nova Research, Inc., 1900 Elkin St., Suite 230, Alexandria, Virginia 22308, USA
| | - Christopher R Field
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Duane A Rogers
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Russell A Jeffries
- Nova Research, Inc., 1900 Elkin St., Suite 230, Alexandria, Virginia 22308, USA
| | - Richard J Colton
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
| | - Susan L Rose-Pehrsson
- Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, D.C. 20375, USA
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