Evaluation of False Alarm Rates of a Walkthrough Detection Portal Designed for Detecting Triacetone Triperoxide (TATP) Vapour from Field Test Results and Receiver Operating Characteristic (ROC) Curves

Evaluation of False Alarm Rates of a Walkthrough Detection Portal Designed for Detecting Triacetone Triperoxide (TATP) Vapour from Field Test Results and Receiver Operating Characteristic (ROC) Curves

Y. Takada H. Nagano Y. Kawaguchi Y. Suzuki E. Nakajima M. Sugiyama M. Sugaya Y. Hashimoto M. Sakairi 

Central Research Laboratory, Hitachi, Ltd, Japan

Tachikawa Office, WDB Co, Ltd, Japan

Page: 
256-264
|
DOI: 
https://doi.org/10.2495/SAFE-V2-N3-256-264
Received: 
N/A
| |
Accepted: 
N/A
| | Citation

OPEN ACCESS

Abstract: 

We have been developing a “walkthrough detection portal system” with the aim of preventing terrorist attacks or criminal bombings in crowded public places. The portal system consists of a vapour sampler, an atmospheric-pressure chemical ionisation (APCI) ion source, and an explosives detector based on ion-trap mass spectrometry (ITMS). The system can detect triacetone triperoxide (TATP) vapour at a high throughput (1,200 persons per hour). We tested the two-portal systems at the automated ticket gate areas of a train station to obtain background signal data from passengers. The field test results for 9,951 passengers indicated that the false positive rate of the portal system for TATP detection was below 0.01% when multi-marker detection logic was used, although it was about 0.5–2.0% with single marker detection (m/z 75, 77 or 91). We used the receiver operating characteristic (ROC) curves obtained from the field test results at the train station and the calibration curves of the walkthrough detection portal system to evaluate the relationship between a true positive rate and a false positive rate. The ROC curves for the TATP vapour indicated the true positive rate of the walkthrough detection portal exceeded 99% with the false positive rate below 0.1%, even when only 1 mL TATP vapour was tested. It is concluded from the ROC curves that this detection portal system has sufficient sensitivity and selectivity for detecting TATP in places where many people come and go.

Keywords: 

homeland security, improvised explosives, mass spectrometry

  References

[1] Schubert, H. & Kuzentsov, A., Detection and Disposal of Improvised Explosives, Springer: Dordrecht, The Netherlands, 2006. doi: http://dx.doi.org/10.1007/978-1-4020-4887-6

[2] Yinon, J., Mass spectrometry of explosives: nitro compounds, nitrate esters, and nitra-mines. Mass Spectrometry. Reviews 1, p. 257, 1982.

[3] McLuckey, S.A., Glish, G.L. & Asano, K.G., Coupling of an atmospheric-sampling ion source with an ion-trap mass spectrometer. Anaytical. Chimica. Acta 225, p. 25, 1989.

[4] Yinon, J. & Zitrin, S., Modern Methods and Applications in Analysis of Explosives, John Wiley and Sons Ltd: New York, 1993.

[5] McLuckey, S.A., Goeringer, D.E., Asano, K.G., Vaidyanathan, G. & Stephenson Jr., J.L., High explosives vapor detection by glow discharge-ion trap mass spectrometry. Rapid Communications. in Mass Spectrometry 10, p. 287, 1996. http://dx.doi.org/10.1002/ (SICI)1097-0231(199602)10:3<287::AID-RCM429>3.0.CO;2-H

[6] Evans, C.S., Sleeman, R., Luke, J. & Keely, B.J., A rapid and efficient mass spectro-metric method for the analysis of explosives. Rapid Communications. in Mass Spectro-metry 16, p. 1883, 2002. doi: http://dx.doi.org/10.1002/rcm.799

[7] Crowson, A. & Beardah, M.S., Development of an LC/MS method for the trace analysis of hexamethylenetriperoxidediamine (HMTD). Analyst 126, p. 1698, 2001.

[8] Xu, X., van de Craats, A.M., Kok, E.M. & de Bruyn, P.C.A.M., Trace analysis of per-oxide explosives by high performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC-APCI-MS/MS) for forensic applications. Journal. Forensic Science 49, p. 1, 2004.

[9] Kojima, K., Sakairi, M., Takada, Y. & Nakamura, J., Vapor detection of TNT and RDX using atmospheric pressure chemical ionization mass spectrometry with counter-flow introduction (CFI). Journal. Mass Spectrometry. Society of Japan 48, p. 360, 2000.

[10] Takada, Y., Nagano, H., Suga, M., Hashimoto, Y., Yamada, M., Sakairi, M., Kusumoto, K., Ota, T. & Nakamura, J., Detection of military explosives by atmospheric pres-sure chemical ionization mass spectrometry with counter flow introduction. Propel-lants, Explosives, Pyrotechnics 27, p. 224, 2002. doi: http://dx.doi.org/10.1002/1521-4087(200209)27:4<224::AID-PREP224>3.0.CO;2-V

[11] Takada, Y., Nagano, H., Suzuki, Y., Sugiyama, M., Nakajima, E., Hashimoto, Y. & Sakairi, M., High-throughput walkthrough detection portal for counter terrorism: detec-tion of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ioniza-tion ion trap mass spectrometry. Rapid Communications. in Mass Spectrometry 25, p. 2448, 2011.

[12] Takada, Y., Suzuki, Y., Nagano, H., Sugiyama, M., Nakajima, E., Sugaya, M., Hashimoto, Y. & Sakairi, M., High-Throughput Walkthrough Detection Portal as a Measure for Counter Terrorism: Design of a Vapor Sampler for Detecting Triacetone Triperoxide Vapor by Atmospheric-Pressure Chemical-Ionization Ion-Trap Mass Spec-trometry. IEEE Sensors Journal, in press.

[13] Sugiyama, M., Hasegawa, H. & Hashimoto, Y., Mass-selective axial ejection from a linear ion trap with a direct current extraction field. Rapid Communications. in Mass Spectrometry 23, p. 2917, 2009.

[14] Sigman, M.E., Clark, C.D., Fidler, R., Geiger, C.L. & Clausen, C.A., Analysis of triac-etone triperoxide by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry by electron and chemical ionization. Rapid Communica-tions. in Mass Spectrometry 20, p. 2851, 2006.