Analysis of Flammable residues
Headspace Technique –
◦ Material placed in airtight container
◦ Heat container to release volatile residue
◦ Vapors pulled out of the top of container
◦ Vapor Concentration –
◦ Charcoal coated strip placed in container with
material
◦ Heated for a period of time
◦ Charcoal absorbs volatile residue
◦ Wash off volatile residue with CS2
Low Explosives
an explosive with a velocity
of detonation less than 1,000 meters per second
◦ Black powder – 75% potassium nitrate, 15%
charcoal, 10% sulfur
◦ Nitrocellulose
◦ Smokeless powder –nitrocellulose and nitroglycerin
◦ Chlorate mixtures
◦ Gas-air mixtures – 5.3% to 13.9% methane in air by
volume
High Explosives
an explosive with a velocity of detonation greater than 1,000 meters per second
Primary Explosive
a high explosive that is easily detonated by heat, shock, or friction ◦ Lead azide ◦ Lead styphnate ◦ Diazodinitropheno
Secondary Explosive
a high explosive that is
relatively insensitive to heat, shock, or
friction
◦ TNT (trinitotoluene)
◦ PETN (pentaerythritol tetranitrate)
◦ RDX (cyclotrimethylenetrinitramine)
◦ Tetryl (2,4,6-trinitrophenylmethylnitramine)
Ammonium nitrate
a strong oxidizer that is mixed with a fuel forming a stable explosive
◦ ANFO (ammonium nitrate fuel oil)
Explosives
Detonators - initiate explosion of high explosives
Blasting caps are most often used as detonators
Evidence of Explosives
ion mobility spectromemter microscopy color spot test fluorescent and magnetic chip added to commercial explosives Thin-Layer Chromatography (TLC) High-Performance Liquid Chromatography (HPLC) Gas Chromatography (GC) Infrared Spectroscopy X-ray diffraction
Gun structure
striker and barrel will leave marks
need to collect ejected cartridges to make sure find all projectiles
Nitrocellulose is known as guncotton. What is this explosive classified?
low Explosive
Gun Barrel Rifling are made by
hand, hammer forging or electrochemical etching
where to find gun shot residue
on suspect, victim or material that may have been in contact with gun
presence of gun shot residue ≠someone fired a gun
No, the person may have touched the gun soon after it was fired; the person may have been cleaning a gun
Rifling Characteristics
Caliber (size of bullet)
Number of lands and grooves
Direction of twist of the rifling
Widths of lands and grooves
What are the tool marks
Compression – a tool is pressed into a softer
material
Sliding – a tool slides across a surface
Cutting – combination of compression and
sliding
Drug Classification (3)
Natural Product – a drug that is derived
directly from a plant
Semi-Synthetic – a drug that is derived
indirectly from plant matter
Synthetic – a drug that is synthesized rather
than extracted from a plant
Acid drugs (b/c of OH groups)
GHB – gamma hydroxybutyric acid
GBL – gamma butyrolactone
Marijuana and Hashish
acidic Drugs - Steroid
naturally occurring lipid composed of four fused rings
Neurotransmitters – a substance in the body
that carries information from one nerve cell
to another
dopamine; serotonin ( by body)
amphetamine, methamphetamine (synthetic)
Alkaloid
opiate:
compound derived from or related to the extract of the unripe seed pods of the opium poppy morphine, codeine, MAM, Heroin, cocaine (not opiate)
Endorphin
Interact with receptors in the brain to reduce perception of pain and stress
Analgesic
Analgesic – alleviate pain;
such as aspirin, acetaminophen and ibuprofen
Depressant
Depressant – causes depression of central nervous system; such as alcohol, barbiturates and tranquilizers
Hallucinogen
Hallucinogen – causes changes in thoughtsand perception;
such as marijuana, LSD and mescaline
