Laboratory Recovery of Flammable Residues

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What is the purpose of comparing the chromatographic pattern of an unknown sample to known petroleum products?

Determining the explosive nature of the unknown sample

Identifying the source of the unknown sample (correct)

Assessing the color of the unknown sample

Measuring the density of the unknown sample

Where can a forensic analyst find a searchable library to compare the chromatograms of accelerant standards?

Local library archives

Forensic journal articles

Chemistry textbooks

ILRC website (correct)

What technique can simplify complex chromatographic patterns in forensic analysis?

Gas chromatography/mass spectrometry (correct)

Column chromatography

Paper chromatography

Thin-layer chromatography

What is the characteristic nature of explosives that distinguishes them from other substances?

Rapid oxidation reaction Signup and view all the answers

Which of the following is an example of a low explosive used widely?

Black powder Signup and view all the answers

What is the term for the speed of decomposition exhibited by low explosives confined to containers?

Deflagration Signup and view all the answers

What is the purpose of placing a charcoal strip in the airtight debris container during heating?

To absorb much of the vapors for recovery of accelerant residues. Signup and view all the answers

How are the volatile residues in fire-scene debris trapped during the laboratory recovery process?

By heating the airtight container and capturing the vapor in its airspace. Signup and view all the answers

Why is a syringe used after heating the container during laboratory recovery of flammable residues?

To remove the trap vapor for injection into a gas chromatograph. Signup and view all the answers

What role does the solvent play in the vapor concentration technique?

Recovering accelerant vapors absorbed by a charcoal strip. Signup and view all the answers

Why is gas chromatography considered a sensitive and reliable instrument for detecting and characterizing flammable residues?

It separates hydrocarbon components and produces characteristic chromatographic patterns. Signup and view all the answers

How can a forensic analyst identify the accelerant used in an arson case using gas chromatography?

By comparing gas chromatographic peaks from fire-scene debris to known flammable liquids. Signup and view all the answers

What is the purpose of using the ion mobility spectrometer mentioned in the text?

Identifying explosive residues in materials collected for laboratory examination Signup and view all the answers

Why is it essential to collect and preserve loose soil and debris from the interior of a crater at the origin of an explosion?

To analyze the debris by gas chromatography/mass spectrometry Signup and view all the answers

What is the purpose of rinsing recovered debris with organic solvents in forensic analysis?

To identify accelerants used in the explosion Signup and view all the answers

Why is it important to use sealed air-tight containers for materials collected for laboratory examination?

To prevent contamination of nearby containers by diffusing explosives Signup and view all the answers

What type of testing procedure is NOT mentioned as part of the analysis conducted on recovered debris?

Vapor concentration technique Signup and view all the answers

Why are confirmatory identification tests performed on unexploded materials?

To confirm the presence of explosives in the unexploded materials Signup and view all the answers