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Detection of Organic Peroxide Explosives Through The Fenton Reaction

Detection of Organic Peroxide Explosives Through The Fenton Reaction. I. Francis Cheng, Derek F. Laine, Christopher Roske University of Idaho Moscow, ID 83844-2343 Email: ifcheng@uidaho.edu Tel.: 208-885-6387 Fax: 208-885-6173 Homepage: http://www.chem.uidaho.edu/faculty/ifcheng/

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Detection of Organic Peroxide Explosives Through The Fenton Reaction

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  1. Detection of Organic Peroxide Explosives Through The Fenton Reaction I. Francis Cheng, Derek F. Laine, Christopher Roske University of Idaho Moscow, ID 83844-2343 Email: ifcheng@uidaho.edu Tel.: 208-885-6387 Fax: 208-885-6173 Homepage: http://www.chem.uidaho.edu/faculty/ifcheng/ Acknowledgement: NSF-SGER University of Idaho, IF Cheng, DF Laine, C Roske

  2. Triacetone Triperoxide (TATP) • Wikipedia http://en.wikipedia.org/wiki/Acetone_peroxide • Acetone peroxide (triacetone triperoxide, peroxyacetone, TATP, TCAP) is an organic peroxide and a primary high explosive. University of Idaho, IF Cheng, DF Laine, C Roske

  3. Hexamethylenetriperoxide (HMTD) • Wikipedia - http://en.wikipedia.org/wiki/Hexamethylene_triperoxide_diamine Oxley, J.C.; Smith, J.L.; Chen, H.; Cioffi, Eugene. Thermochim. Acta 2002, 388, 215-225. University of Idaho, IF Cheng, DF Laine, C Roske

  4. Outline • Background • Dangers • Recent News • Need for Detection Systems • Fast • Field Portable (handheld) • Selective and LOD • Electrochemical Detection Via Fenton Reaction University of Idaho, IF Cheng, DF Laine, C Roske

  5. TATP & HMTD – the threat • Due to the cost and ease with which the precursors can be obtained, acetone peroxide is commonly manufactured by those without the resources needed to manufacture or buy more sophisticated explosives. When the reaction is carried out without proper equipment the risk of an accident is significant. • http://en.wikipedia.org/wiki/Acetone_peroxide University of Idaho, IF Cheng, DF Laine, C Roske

  6. TATP – Ease of Synthesis • 3H2O2 + 3CH3COCH3= ((CH3)2COO)3 + 3H2O • Ice Bath • 3% H2O2 (30% or more preferable) • Acetone (paint thinner) • H2SO4 (battery acid) University of Idaho, IF Cheng, DF Laine, C Roske

  7. Ease of HMTD Synthesis • http://business.fortunecity.com/executive/674/hmtd.html • Hexamethylenetetramine + Citric Acid + H2O2 HMTD University of Idaho, IF Cheng, DF Laine, C Roske

  8. TATP & HMTD – physiochemical characteristics • TATP • Shock Sensitive • Heat Sensitive • High V.P. 7 Pa @ 300K • HMTD • Shock Sensitive • Heat Sensitive • Low VP • Neither have any commercial or military value. • Propellants, Explosives, Pyrotechnics 30 (2005)127 • J. Am. Chem. Soc.2005, 127, 1146-1159 University of Idaho, IF Cheng, DF Laine, C Roske

  9. TATP – Most Recent News • NY Times Sept. 5, 2007 • FRANKFURT, Sept. 5 — The German police have arrested three Islamic militants suspected of planning large-scale terrorist attacks against several sites frequented by Americans, including discos, bars, airports, and military installations. • She said the suspects had amassed large amounts of hydrogen peroxide, the main chemical used to manufacture the explosives used in the suicide bombings in London in July 2005. University of Idaho, IF Cheng, DF Laine, C Roske

  10. TATP & HMTD – London Subway Bombings • July 7, 2005 http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/05/uk_enl_1121567244/img/1.jpg University of Idaho, IF Cheng, DF Laine, C Roske

  11. TATP & HMTD Incidents • 2006 – London airline bombing plot – HMTD • 2005 - Joel Henry Hinrichs III – University of Oklahoma. – TATP. • 2001 - Richard Reid, Shoe Bomber – TATP • 1999 - Millennium bomber Ahmed Ressam. 124 pounds of HMTD • 1994/95 – Bojinka Plot – TATP? HMTD? • 1994 – Philippines Airlines - TATP • 1980’s – present - West Bank Israel – TATP “Mother of Satan” University of Idaho, IF Cheng, DF Laine, C Roske

  12. TATP – TSA Fluid Ban • Effective November 10, 2006, the TSA has advised that travelers may now carry through security checkpoints travel-size toiletries (3.4 ounces/100 ml or less) that fit comfortably in ONE, QUART-SIZE, clear plastic re-sealable bag. • The 3-1-1 Kit contains six 2-1/2 oz and four 1-1/2 oz flexible squeeze tubes, plus one 1-3/4 oz Envirosprayer. • Kit is also compliant with the new International Security Measures Accord. • http://www.easytravelerinc.com/ University of Idaho, IF Cheng, DF Laine, C Roske

  13. TATP & HMTD Detection - The Challenge • The Need for a Fast Portable Detector • Innocuous Appearing White Powder • Dogs are only moderately successful at detection of TATP & HMTD - Expensive • Lacks Chromophoric Groups (not detectable by UV-vis absorbance) University of Idaho, IF Cheng, DF Laine, C Roske

  14. TATP & HMTD – Detector Requirements • Unknown Materials – Public Safety, e.g. Airports • High Selectivity – Low Limits of Detection not Required • Air Samples, e.g. Airports • Moderate Selectivity– Low Limits of Detection Required • Debris at Post-Explosion Sites • High Selectivity– Low Detection Limits • Field Portability Schulte-Ladbeck, R.; Vogel, M.; Karst, URecent methods for the determination of peroxide-based explosivesAnal. Bioanal. Chem. 386 559-565 (2006) University of Idaho, IF Cheng, DF Laine, C Roske

  15. TATP & HMTD - Detectors • IR-Raman • High Selectivity – Relatively High LOD • Fluorescence/UV-vis Absorbance • Low LOD requires tagging • Ion Mobility • Good Selectivity, moderate LOD • HPLC or GC • Excellent Selectivity and LOD University of Idaho, IF Cheng, DF Laine, C Roske

  16. TATP & HMTD – State of Detectors • Costs • Lack of Field Portability • Ideal – Handheld Sensor • May Require Knowledgeable User • e.g. Commercial Glucose Sensors, electrochemical devices University of Idaho, IF Cheng, DF Laine, C Roske

  17. The Fenton Reaction H2O2 + e- HO• + HO- Fe(II)  Fe(III) + e- Fe(II) + H2O2  Fe(III) + HO• + HO- H.J.H. Fenton. J. Chem. Soc. 1894, 65, 889. F. Haber and J.J. Weiss. Proc. Roy. Soc. London, Ser. A. 1934, 147, 332. University of Idaho, IF Cheng, DF Laine, C Roske

  18. The Fenton Reaction • FeIIIEDTA + e- = FeIIEDTA • FeIIEDTA + H2O2 = FeIIIEDTA + HO- + HO∙ (fast) • H2O2 + e- = HO- + HO∙ (slow) University of Idaho, IF Cheng, DF Laine, C Roske

  19. a b EC’ Voltammetry with the Fenton Reaction Mechanism • Cyclic voltammetry • 0.1 mM FeIIIEDTA • 0.1M KCl, 0.1 M chloroacetic acid (pH=3.3) under N2 purge • 8 mM TBHP or H2O2 • 0 mM TBHP. University of Idaho, IF Cheng, DF Laine, C Roske

  20. TATP & HMTD – Detection by Electrochemical Means • Proposed Basis For Detection • Fenton Reaction for Organic Peroxides RO-OR + FeIIEDTA  RO- + RO· + FeIIIEDTA University of Idaho, IF Cheng, DF Laine, C Roske

  21. TATP & HMTD – Electrochemical DetectionReaction with Organic Peroxides is not Spontaneous RO-OR + FeIIEDTA  N.R. E0 RO-OR + e-  RO- + RO· <-0.5 V FeIIEDTA  FeIIIEDTA + e- 0.1 V Ecell = Ecath – Eanod -0.6 V University of Idaho, IF Cheng, DF Laine, C Roske

  22. TATP & HMTD – Electrochemical DetectionReaction with Peroxides and Hydroperoxides is Spontaneous E0 RO-OH + e-  RO- + HO· ≈0.4 V HO-OH + e-  HO- + HO· 0.8 V FeIIEDTA + RO-OH/HO-OH FeIIIEDTA + RO∙/HO∙/H+ • Requires that TATP & HMTD be degraded University of Idaho, IF Cheng, DF Laine, C Roske

  23. TATP – Degradation to HOOH/ROOH • Acid degradation • TATP + H+ H2O2 + Products • Concentrated HCl • 1-10 minutes University of Idaho, IF Cheng, DF Laine, C Roske

  24. HMTD Degradation • HMTD  products + H2O2 • Rapid (almost immediate) & Spontaneous • With addition of FeIIIEDTA • pH effect – 2.1 University of Idaho, IF Cheng, DF Laine, C Roske

  25. A B Figure 1. Cyclic voltammograms of two solutions both containing 10 mM TATP and 1 mM FeIIIEDTA under dearated conditions, 30 mV/s. A) Acid treated TATP. B) Non-acid treated TATP. TATP – Cyclic Voltammograms after Acid Digestion University of Idaho, IF Cheng, DF Laine, C Roske

  26. B Chronoamperometry • Background: FeIIIEDTA + e- = FeIIEDTA FeIIEDTA + O2 = FeIIIEDTA + O2.- • E- step = -400 mV v. Ag/AgCl • 1 mM FeIIIEDTA • 0.1 NaAc/HAc buffer pH 3 • 40% Acetonitrile • Vigorous Stirring • 0.04 mM acid treated TATP • B) 0 mM TATP A University of Idaho, IF Cheng, DF Laine, C Roske

  27. TATP calibration curve • The detection limit is 0.9 μM = 3Sb/m, • Sb = standard deviation of blanks • m = slope of calibration curve • Sensitivity of 0.025 mA/mM TATP. • Background subtracted • Error bars indicate one standard deviation. University of Idaho, IF Cheng, DF Laine, C Roske

  28. HMTD analysis • E- step = -400 mV v. Ag/AgCl • 1 mM FeIIIEDTA • Vigorous Stirring • Detection limit 30 μM = 3Sb/m, • Sb = standard deviation of blanks • m = slope of calibration curve • Error bars indicate one standard deviation. Increasing [HMTD] University of Idaho, IF Cheng, DF Laine, C Roske

  29. Detection of TATP in technical mixtures • Significant concentrations of HOOH and ROOH. • Provides Target for the Detection of Technical Mixtures • TATP purification requires MeOH Recrystallization – More Stable than Technical Mixtures University of Idaho, IF Cheng, DF Laine, C Roske

  30. Detection of HOOH & ROOH E0 RO-OH + e-  RO- + HO· ≈0.4 V HO-OH + e-  HO- + HO· 0.8 V FeIIEDTA + RO-OH/HO-OH FeIIIEDTA + RO∙/HO∙/H+ Detection Limits H2O2 0.4 μM tert-butyl hydroperoxide 21 μM University of Idaho, IF Cheng, DF Laine, C Roske

  31. *Wang, Joseph et al, Analyst2007, 132, 560-565. Literature University of Idaho, IF Cheng, DF Laine, C Roske

  32. Other Needs for H2O2 Detection • Glucose Detector Glucose + H2O + O2 Gluconic Acid + H2O2 H2O2 2H+ + O2 + 2e- (slow) • Immobilized HRP • Limited Linear Range to 3 mM University of Idaho, IF Cheng, DF Laine, C Roske

  33. Advantages of H2O2 via Fenton Reaction • This Work: FeIIIEDTA + e- = FeIIEDTA (fast) FeIIEDTA + H2O2 = FeIIIEDTA + HO- + HO∙(fast) • Does not require immobilization of enzymes • Less Expensive • Linear Range LOD – 100 mM University of Idaho, IF Cheng, DF Laine, C Roske

  34. Summary • TATP - 0.9 µM LOD Instrumental • HMTD - 30 µM LOD Method • HOOH – 0.4 µM LOD Instrumental • ROOH – 21 µM LOD Instrumental • O2 interference • FeIIEDTA + O2 FeIIIEDTA + O2.- • HOOH/ROOH – No Pretreatment • Requires Acid Pretreatment • TATP – 1-10 min. Sample Pretreatment • HMTD – Instantaneous University of Idaho, IF Cheng, DF Laine, C Roske

  35. Summary • Proof of concept • No modified electrodes or enzymes required. Reagents can stand up to long term storage. • Allows for development of simple, handheld & inexpensive devices, e.g. glucose sensors • Not a stand-off detection device • High TATP VP may allow for gas phase sensor University of Idaho, IF Cheng, DF Laine, C Roske

  36. Future Work • Elimination of O2 interference • Metal Complex Reduction Potential • Kinetics of H2O2 vs. O2 reduction • Optimal Hydrolysis • Design of probes • Air Samples • Liquid Sample University of Idaho, IF Cheng, DF Laine, C Roske

  37. Acknowledgements • National Science Foundation University of Idaho, IF Cheng, DF Laine, C Roske

  38. Abstract - Detection of Organic Peroxide Explosives through the Fenton Reaction There is an urgent need for methods and techniques that are able to detect quantitatively and qualitatively peroxide based explosives, especially triacetone triperoxide or TATP. The basic chemistries for such endeavor have not been fully described. This investigation will examine the electrochemical mediation of the Fenton Reaction as a basis for detection of this class of explosives. The mediation takes place as a result of the homogeneous Fenton Reaction and the electro-reduction of an FeIII complex to FeII followed by oxidation by either a hydroperoxide or hydrogen peroxide: FeIIcomplex + RO-OH  FeIIIcomplex + RO- + HO∙ FeIIcomplex + HO-OH  FeIIIcomplex + HO- + HO∙ The current due to the electro-reduction of the FeIII complex is proportional to the square root of the peroxide concentration. The process is expected to be rapid, robust, and inexpensive. We will report on the detection limits, kinetics, optimal conditions for the degradation of TATP to hydroperoxides and H2O­2, and the role of the chelate of that iron complex. The latter is based on considerations of the structure-activity relationships developed by cyclic voltammetric studies. University of Idaho, IF Cheng, DF Laine, C Roske

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