Analytical StrategyForensic Analysis - Explosives

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Dr. Sandro Imhasly

Head of Analytics/Explosives Unit

Bomb Disposal Expert

sandro.imhasly@for-zh.ch

Organigramm FOR

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FOR-ZED

Koordination

PyrotechnikEntwicklung Analytik/Sprengstoffe

Organization ZED

ZEDBEXNEDEX

Entschärferstützpunkte CH

Service duties ZED

Explosion / Detonation

Explosions

mechanical explosion

gas/air explosion

detonation

Mechanical explosion

Gas/air explosion

Gas/air explosion

Gas/air explosion - trace pattern

large wreckage

no crater formation

Detonation

Detonation - trace pattern

Explosion centre with crater

Detonation

Detonation

Pressure/Push effect

Pull effect

Detonation

Question / Discussion

Question / Discussion

• What analytical methods would you propose for the determination of the diverse explosives components? What are the advantages and disadvantages of the proposed methods?

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bulk / trace

Bulk explosives

• Explosive Testing Kits

• IMS

• IR

• Raman

• Flame test

• XRD / XRF

• Microscopy

• TLC

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Raman – Attention!

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• Do not use for bulk explosives! The added energy of the laser can cause the substance to explode.

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Trace explosives

• IC-MS

• GC-(MS)

• HPLC-DAD

• HPLC-MS

• ICP-MS

• AAS

• IMS

• DART-TOF-MS

• ect.

Question / Discussion

• What analytical methods would you propose for the determination of the diverse explosives components? What are the advantages and disadvantages of the proposed methods?

• How would you prepare the gathered evidence for instrumental analysis using the proposed methods?

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bulk / trace

extractionwater/org. solvent

Explosives

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Chlorate/Perchlorate mixtures Ammonium nitrate / fuel oil

• Always mixtures:• Al, Mg• Sugar• Fuel • Sulfur

• Black powder, flash powder

• Widely used in fireworks

• XRD/XRF

• IC-MS

• AAS

• ICP-MS

• IMS

Explosives

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Hexamethylene triperoxide diamine (HMTD)

Triacetone triperoxide (TATP) Mannitol hexanitrate

• HPLC-MS (ESI/APCI)• GC-MS • IMS

• HME – homemade explosives

• Unsafe to handle

Explosives

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Trinitrotoluene (TNT) Pentaerythritol tetranitrate (PETN) Cyclotrimethylenetrinitramine (RDX) Nitroglycerine (NG)

• HPLC-MS (ESI/APCI)

• GC-MS

• IMS

Explosives

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Nitrocellulose

• Problem: not a "clear defined" molecule

• Trace analysis only possible by determination of additives• Camphor• Akardite• Centralite• Diphenylamine

• HPLC-MS / GC-MS

Question / Discussion• How would you proceed gathering evidence? What do you consider

important points?

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Gathering evidence - Blown upmailbox

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Sampling material

Explosives residues set

2 m2

Documentation

Documentation

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Question / Discussion• How would you proceed gathering evidence? What do you consider

important points?

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Prevention of Mix-up

Prevention of Contamination

Gathering Reference Samples

Prevention of Degradation

Question / Discussion• How would you proceed gathering evidence? What do you consider

important points?

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Prevention of Mix-up

Prevention of Contamination

Gathering Reference Samples

Prevention of Degradation

Reference Samples

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August 2014: Einsatz Burg AG

Samples (???)

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Question / Discussion• What is the point of quantitative analysis of traces of explosives in

offences?

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Question / Discussion• What is the point of quantitative analysis of traces of explosives in

offences?

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Conclusions on the quantity of explosives used can only bedrawn from the damage pattern.

Questions?