Reported for the first time are receiver operating characteristic (ROC) curves constructed to describe the performance of a sorbent-coated disk, planar solid phase microextraction (PSPME) unit for non-contact sampling of a variety of volatiles. The PSPME is coupled to ion mobility spectrometers (IMSs) for the detection of volatile chemical markers associated with the presence of smokeless powders, model systems of explosives containing diphenylamine (DPA), 2,4-dinitrotoluene (2,4-DNT) and nitroglycerin (NG) as the target analytes. The performance of the PSPME-IMS was compared with the widely accepted solid-phase microextraction (SPME), coupled to a GC-MS. A set of optimized sampling conditions for different volume containers (1–45 L) with various sample amounts of explosives, were studied in replicates ( n = 30) to determine the true positive rates (TPR) and false positive detection rates (FPR) for the different scenarios. These studies were obtained in order to construct the ROC curves for two IMS instruments (a bench-top and field-portable system) and a bench top GC-MS system in low and high clutter environments. Both static and dynamic PSPME sampling were studied in which 10–500 mg quantities of smokeless powders were detected within 10 min of static sampling and 1 min of dynamic sampling.
References
[1]
Verkouteren, J.R.; Coleman, J.L.; Fletcher, R.A.; Smith, W.J.; Klouda, G.A.; Gillen, G. A method to determine collection efficiency of particles by swipe sampling. Meas. Sci. Technol. 2008, 19, 115101.
[2]
Guerra-Diaz, P.; Gura, S.; Almirall, J.R. Dynamic planar solid phase microextraction—ion mobility spectrometry for rapid field air sampling and analysis of illicit drugs and explosives. Anal. Chem. 2010, 82, 2826–2835.
[3]
Gura, S.; Guerra-Diaz, P.; Lai, H.; Almirall, J.R. Enhancement in sample collection for the detection of MDMA using a novel planar SPME (PSPME) device coupled to ion mobility spectrometry (IMS). Drug Test. Analy. 2009, 1, 355–362.
[4]
Fan, W.; Young, M.; Canino, J.; Smith, J.; Oxley, J.; Almirall, J. Fast detection of triacetone triperoxide (TATP) from headspace using planar solid-phase microextraction (PSPME) coupled to an IMS detector. Anal. Bioanal. Chem. 2012, 403, 401–408.
[5]
Cotte-Rodriguez, I.; Justes, D.R.; Nanita, S.C.; Noll, R.J.; Mulligan, C.C.; Sanders, N.L.; Cooks, R.G. Analysis of gaseous toxic industrial compounds and chemical warfare agent simulants by atmospheric pressure ionization mass spectrometry. Analyst 2006, 131, 579–589.
[6]
Van Schalkwyk, J.; Hopley, L. The Magnificent ROC(Receiver Operating Characteristic Curve). 2001. Available online: http://www.anaesthetist.com/mnm/stats/roc/Findex.htm (accessed on 18 June 2013).
[7]
Zou, K.H.; O'Malley, A.J.; Mauri, L. Receiver-operating characteristic analysis for evaluating diagnostic tests and predictive models. Circulation 2007, 115, 654–657.
[8]
Zweig, M.H.; Campbell, G. Receiver-operating characteristic (ROC) plots: A fundamental evaluation tool in clinical medicine. Clin. Chem. 1993, 39, 561–77.
[9]
Marin, D.; Ibrahim, A.R.; Lucas, C.; Gerrard, G.; Wang, L.H.; Szydlo, R.M.; Clark, R.E.; Apperley, J.F.; Milojkovic, D.; Bua, M.; et al. Assessment of BCR-ABL1 transcript levels at 3 months is the only requirement for predicting outcome for patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors. J. Clin. Oncol. 2012, 30, 232–238.
[10]
Jilaihawi, H.; Kashif, M.; Fontana, G.; Furugen, A.; Shiota, T.; Friede, G.; Makhija, R.; Doctor, N.; Leon, M.B.; Makkar, R.R. Cross-sectional computed tomographic assessment improves accuracy of aortic annular sizing for transcatheter aortic valve replacement and reduces the incidence of paravalvular aortic regurgitation. J. Am. Coll. Cardiol. 2012, 59, 1275–1286.
[11]
Kessler, R.C.; Andrews, G.; Colpe, L.J.; Hiripi, E.; Mroczek, D.K.; Normand, S.L. T.; Walters, E.E.; Zaslavsky, A.M. Short screening scales to monitor population prevalences and trends in non-specific psychological distress. Psychol. Med. 2002, 32, 959–976.
[12]
Kessler, R.C.; Barker, P.R.; Colpe, L.J.; Epstein, J.F.; Gfroerer, J.C.; Hiripi, E.; Howes, M.J.; Normand, S.L.T.; Manderscheid, R.W.; Walters, E.E.; et al. Screening for serious mental illness in the general population. Arch. Gen. Psychiatry 2003, 60, 184–189.
[13]
Lowe, B.; Spitzer, R.L.; Grafe, K.; Kroenke, K.; Quenter, A.; Zipfel, S.; Buchholz, C.; Witte, S.; Herzog, W. Comparative validity of three screening questionnaires for DSM-IV depressive disorders and physicians′ diagnoses. J. Affect. Disord. 2004, 78, 131–140.
[14]
De Lucia, F.C.; Gottfried, J.L.; Munson, C.A.; Miziolek, A.W. Multivariate analysis of standoff laser-induced breakdown spectroscopy spectra for classification of explosive-containing residues. Appl. Opt. 2008, 47, G112–G121.
[15]
Michalopoulou, Z.H.; Mukherjee, S.; Hor, Y.L.; Su, K.; Liu, Z.W.; Barat, R.B.; Gary, D.E.; Federici, J.F. RDX Detection with THz Spectroscopy. J. Infrared Millim. Terahertz Waves 2010, 31, 1171–1181.
[16]
Jander, P.; Noll, R. Automated detection of fingerprint traces of high explosives using ultraviolet raman spectroscopy. Appl. Spectrosc. 2009, 63, 559–563.
[17]
Yuksel, S.E.; Dubroca, T.; Hummel, R.E.; Gader, P.D. Differential reflection spectroscopy: A novel method for explosive detection. Acta Phys. Pol. A 2013, 123, 263–264.
[18]
Perez-Garrido, A.; Helguera, A.M.; Borges, F.; Cordeiro, M.; Rivero, V.; Escudero, A.G. Two new parameters based on distances in a receiver operating characteristic chart for the selection of classification models. J. Chem. Inf. Model. 2011, 51, 2746–2759.
[19]
Oh, H.J.; Pradhan, B. Application of a neuro-fuzzy model to landslide-susceptibility mapping for shallow landslides in a tropical hilly area. Comput. Geosci. 2011, 37, 1264–1276.
[20]
Brozell, S.R.; Mukherjee, S.; Balius, T.E.; Roe, D.R.; Case, D.A.; Rizzo, R.C. Evaluation of DOCK 6 as a pose generation and database enrichment tool. J. Comput. Aided Mol. Des. 2012, 26, 749–773.
[21]
Carrano, J. Chemical and Biological Sensor Standards Study. In DARPA Microsystems Technology Office; US Department of Defense: Arlington, VA, USA, 2005.
[22]
Fraga, C.G.; Melville, A.M.; Wright, B.W. ROC-curve approach for determining the detection limit of a field chemical sensor. Analyst 2007, 132, 230–236.
[23]
Heramb, R.M.; McCord, B.R. The Manufacture of smokeless powders and their forensic analysis: A brief review. Forensic Sci. Commun. 2002, 4.
[24]
Joshi, M.; Rigsby, K.; Almirall, J.R. Analysis of the headspace composition of smokeless powders using GC–MS, GC-μECD and ion mobility spectrometry. Forensic Sci. Int. 2011, 208, 29–36.
[25]
Joshi, M.; Delgado, Y.; Guerra, P.; Lai, H.; Almirall, J.R. Detection of odor signatures of smokeless powders using solid phase microextraction coupled to an ion mobility spectrometer. Forensic Sci. Int. 2009, 188, 112–118.
[26]
Stull, D.R. Vapor pressure of pure substances organic compounds. Ind. Eng. Chem. 1947, 39, 517–540.
[27]
Pella, P.A. Measurement of the vapor pressures of tnt, 2,4-DNT, 2,6-DNT, and EGDN. J. Chem. Thermodyn. 1977, 9, 301–305.
[28]
United States Department of the Army. Military Explosives; Headquarters, Department of the Army: Charlottesville, VA, USA, 1989.
[29]
Oxley, J.C.; Smith, J.L.; Brady, J.E.; Brown, A.C. Characterization and analysis of tetranitrate esters. Propellants Explos. Pyrotech. 2012, 37, 24–39.
[30]
Yinon, J. Forensic and Environmental Detection of Explosives.; Wiley: New York, NY, USA, 1999.
[31]
Beveridge, A. Forensic Investigation of Explosions, 2nd ed. ed.; CRC Press Inc.: Boca Raton, FL, USA, 2011.
[32]
Lorenzo, N.; Wan, T.; Harper, R.; Hsu, Y.-L.; Chow, M.; Rose, S.; Furton, K. Laboratory and field experiments used to identify Canis lupus var. familiaris active odor signature chemicals from drugs, explosives, and humans. Anal. Bioanal. Chem. 2003, 376, 1212–1224.
[33]
Lai, H.; Leung, A.; Magee, M.; Almirall, J. Identification of volatile chemical signatures from plastic explosives by SPME-GC/MS and detection by ion mobility spectrometry. Anal. Bioanal. Chem. 2010, 396, 2997–3007.
