detection of organic peroxide explosives through the fenton reaction
DESCRIPTION
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: [email protected] Tel.: 208-885-6387 Fax: 208-885-6173 Homepage: http://www.chem.uidaho.edu/faculty/ifcheng/ - PowerPoint PPT PresentationTRANSCRIPT
I. Francis Cheng, Derek F. Laine, Christopher Roske
University of IdahoMoscow, ID 83844-2343
Email: [email protected] Tel.: 208-885-6387Fax: 208-885-6173
Homepage: http://www.chem.uidaho.edu/faculty/ifcheng/
Acknowledgement: NSF-SGERPittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske1
Detection of Organic Peroxide Explosives Through The Fenton
ReactionOO
O
O O
O
Triacetone Triperoxide (TATP)
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske2
Wikipedia http://en.wikipedia.org/wiki/Acetone_peroxide
Acetone peroxide (triacetone triperoxide, peroxyacetone, TATP, TCAP) is an organic peroxide and a primary high explosive.
Hexamethylenetriperoxide (HMTD)
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske3
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.
Outline
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske4
BackgroundDangersRecent News
Need for Detection SystemsFastField Portable (handheld)Selective and LOD
Electrochemical Detection Via Fenton Reaction
TATP & HMTD – the threat
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske5
• 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
TATP – Ease of Synthesis
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske6
3H2O2 + 3CH3COCH3= ((CH3)2COO)3 + 3H2O
Ice Bath3% H2O2 (30% or more preferable)Acetone (paint thinner)H2SO4 (battery acid)
Ease of HMTD Synthesis
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske7
http://business.fortunecity.com/executive/674/hmtd.html
Hexamethylenetetramine + Citric Acid + H2O2 HMTD
TATP & HMTD – physiochemical characteristics
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske8
TATPShock SensitiveHeat SensitiveHigh V.P. 7 Pa @
300K
HMTD Shock Sensitive Heat Sensitive Low VP
•Neither have any commercial or military value.
Propellants, Explosives, Pyrotechnics 30 (2005)127J. Am. Chem. Soc. 2005, 127, 1146-1159
TATP – Most Recent News
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske9
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.
TATP & HMTD – London Subway Bombings
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske10
July 7, 2005
http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/05/uk_enl_1121567244/img/1.jpg
TATP & HMTD Incidents
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske11
2006 – London airline bombing plot – HMTD 2005 - Joel Henry Hinrichs III – University of
Oklahoma. – TATP. 2001 - Richard Reid, Shoe Bomber – TATP1999 - Millennium bomber Ahmed Ressam.
124 pounds of HMTD1994/95 – Bojinka Plot – TATP? HMTD?1994 – Philippines Airlines - TATP1980’s – present - West Bank Israel – TATP
“Mother of Satan”
TATP – TSA Fluid Ban
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske12
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/
TATP & HMTD Detection - The Challenge
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske13
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)
TATP & HMTD – Detector Requirements
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske14
Unknown Materials – Public Safety, e.g. Airports High Selectivity – Low Limits of Detection not Required
Air Samples, e.g. AirportsModerate Selectivity– Low Limits of Detection Required
Debris at Post-Explosion SitesHigh 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)
TATP & HMTD - Detectors
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske15
IR-RamanHigh Selectivity – Relatively High LOD
Fluorescence/UV-vis AbsorbanceLow LOD requires tagging
Ion MobilityGood Selectivity, moderate LOD
HPLC or GCExcellent Selectivity and LOD
TATP & HMTD – State of Detectors
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske16
Costs
Lack of Field PortabilityIdeal – Handheld Sensor
May Require Knowledgeable Usere.g. Commercial Glucose Sensors,
electrochemical devices
The Fenton Reaction
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske17
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.
The Fenton Reaction
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske18
FeIIIEDTA + e- = FeIIEDTA
FeIIEDTA + H2O2 = FeIIIEDTA + HO- + HO∙ (fast)
H2O2 + e- = HO- + HO∙ (slow)
EC’ Voltammetry with the Fenton Reaction Mechanism
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske19
Cyclic voltammetry
•0.1 mM FeIIIEDTA
•0.1M KCl, 0.1 M chloroacetic acid (pH=3.3) under N2 purge
a) 8 mM TBHP or H2O2
b) 0 mM TBHP.
-8.0E-07
1.2E-06
3.2E-06
5.2E-06
-500-400-300-200-1000100200300400
Potential (mV)
Curre
nt (A
)
a
b
TATP & HMTD – Detection by Electrochemical Means
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske20
Proposed Basis For DetectionFenton Reaction for Organic Peroxides
RO-OR + FeIIEDTA RO- + RO· + FeIIIEDTA
TATP & HMTD – Electrochemical DetectionReaction with Organic Peroxides is not
Spontaneous
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske21
RO-OR + FeIIEDTA N.R.E0
RO-OR + e- RO- + RO· <-0.5 VFeIIEDTA FeIIIEDTA + e- 0.1 VEcell = Ecath – Eanod -0.6 V
TATP & HMTD – Electrochemical DetectionReaction with Peroxides and Hydroperoxides is Spontaneous
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske22
E0
RO-OH + e- RO- + HO· ≈0.4 VHO-OH + e- HO- + HO· 0.8 V
FeIIEDTA + RO-OH/HO-OH FeIIIEDTA +
RO∙/HO∙/H+
Requires that TATP & HMTD be degraded
TATP – Degradation to HOOH/ROOH
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske23
Acid degradation
TATP + H+ H2O2 + Products
Concentrated HCl 1-10 minutes
HMTD Degradation
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske24
HMTD products + H2O2
Rapid (almost immediate) & Spontaneous
With addition of FeIIIEDTApH effect – 2.1
TATP – Cyclic Voltammograms after Acid Digestion
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske25
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
-500-400-300-200-1000100
Potential (mV)
Curre
nt (m
A)
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.
Chronoamperometry
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske26
Background:
FeIIIEDTA + e- = FeIIEDTA
FeIIEDTA + O2 = FeIIIEDTA + O2.-
E- step = -400 mV v. Ag/AgCl
1 mM FeIIIEDTA0.1 NaAc/HAc buffer pH 340% AcetonitrileVigorous Stirring
A) 0.04 mM acid treated TATP
B) 0 mM TATP0.013
0.015
0.017
0.019
0.021
0.023
0.025
0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0
Time (s)
Cu
rren
t (m
A)
B
A
TATP calibration curve
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske27
•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.
y = 0.025x + 4E-05
R2 = 0.9999
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
[TATP] mM
Cur
rent
(mA)
HMTD analysis
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske28
0.015
0.03
0.045
0.06
0 20 40 60 80 100 120 140Time (s)
Cu
rren
t (m
A)
y = 1E-05x - 4E-07
R2 = 0.9987
-5.00E-06
0.00E+00
5.00E-06
1.00E-05
1.50E-05
2.00E-05
2.50E-05
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
[HMTD] mM
Cu
rren
t (A
)
Increasing [HMTD]E- step = -400 mV v. Ag/AgCl
1 mM FeIIIEDTAVigorous Stirring
•Detection limit 30 μM = 3Sb/m,
Sb = standard deviation of blanks m = slope of calibration curve
•Error bars indicate one standard deviation.
Detection of TATP in technical mixtures
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske29
Significant concentrations of HOOH and ROOH.
Provides Target for the Detection of Technical Mixtures
TATP purification requires MeOH Recrystallization – More Stable than Technical Mixtures
Detection of HOOH & ROOH
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske30
E0
RO-OH + e- RO- + HO· ≈0.4 VHO-OH + e- HO- + HO· 0.8 V
FeIIEDTA + RO-OH/HO-OH FeIIIEDTA + RO∙/HO∙/H+
Detection LimitsH2O2 0.4 μM
tert-butyl hydroperoxide 21 μM
Literature
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske31
Technique Pre-treatment
Speed (mins)
LOD Simultaneous Detection of TATP/HMTD
Ref
EC’ Fenton TATP
Acid 1-10 1 μM Yes This Work
EC’ Fenton HMTD
None 0 30 μM Yes This Work
HRP Colorimetric
UV 1 0.9 mM No 6*
HRP Fluorescence
UV 30 8 μM No 4*
HPLC Fluorescence
UV 15 2 μM Yes 3*
Amperometric-PBME
UV/laser 1 50nM No 7*
“ Acid 1 55 nM No *Chronoamperometric/ PBME
Acid 1 18 mM No *
*Wang, Joseph et al, Analyst 2007, 132, 560-565.
Other Needs for H2O2 DetectionGlucose Detector
Glucose + H2O + O2 Gluconic Acid + H2O2
H2O2 2H+ + O2 + 2e-
(slow)Immobilized HRPLimited Linear Range to 3 mM
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske32
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 ExpensiveLinear Range LOD – 100 mM
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske33
Summary
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske34
TATP - 0.9 µM LOD InstrumentalHMTD - 30 µM LOD MethodHOOH – 0.4 µM LOD InstrumentalROOH – 21 µM LOD Instrumental
O2 interferenceFeIIEDTA + O2 FeIIIEDTA + O2
.-
HOOH/ROOH – No Pretreatment Requires Acid Pretreatment
TATP – 1-10 min. Sample PretreatmentHMTD – Instantaneous
Summary
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske35
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 deviceHigh TATP VP may allow for gas phase
sensor
Future Work
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske36
Elimination of O2 interferenceMetal Complex Reduction PotentialKinetics of H2O2 vs. O2 reduction
Optimal Hydrolysis
Design of probesAir SamplesLiquid Sample
AcknowledgementsNational Science Foundation
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske37
Abstract - Detection of Organic Peroxide Explosives through the Fenton Reaction
Pittcon 2008 Session 2520-5University of Idaho, IF Cheng, DF Laine, C Roske38
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 H2O 2, 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.