Mrridhul Khajuria
Forensic
Chemistry -I
Explosives; Fire and Arson Investigation;
Forensic Analysis of petroleum Products
1
,Mrridhul Khajuria
Explosives: Introduction, Classification and chemistry of
explosives; Post blast investigation. Systematic examination
of explosive and explosion residues (organic and inorganic)
by colour test and TLC.
Introduction to Fires &Arson Investigation: Introduction to
Thermodynamics and Chemistry of Fire, Investigation of Fire
and Arson, Forensic Analysis of Fire Debris by Instrumental
methods.
Forensic Analysis of Petroleum Products: Introduction to
Petroleum Products and Analysis of Petrol, Kerosene and
Diesel as per BIS Specifications.
2
, Mrridhul Khajuria
Explosives:
These are materials that release a large amount of energy rapidly when
subjected to a specific trigger such as heat, pressure or shock. This energy is
often in the form of violent expansion of gases creating an explosion.
Characteristics:
1. Rapid decomposition: they undergo rapid chemical reactions; converting
solids or liquid substances into gases almost instantaneously.
2. Exothermal reactions: the decomposition Of explosive is highly
exothermic releasing a large amount of heat.
3. Gas generation: a large volume of gas is produced deceiving the
explosion which contributes to the high pressure and shockwave.
4. Pressure and shockwave: the rapid expansion of gases generates high
pressure and a shockwave, which can cause damage to the
surroundings.
Classification of explosives:
1. Based on velocity:
i) low explosives: deflagrate rather than detonate meaning they burn
rapidly but without a supersonic shockwave. the reaction is subsonic
and the explosive produce gas and heat at slower rate. Used in
propellants like gunpowder fireworks etc. Examples black less
powder, smokeless powder.
ii) High explosives: detonate with supersonic shock waves traveling
through the material. The reaction is rapid and violent producing a
powerful shockwave. Used in military mining and demolition.
Examples TNT- tri-Nitro toluene, nitroglycerin etc.
2. Based on sensitivity:
i) Primary explosives: highly sensitive to heat friction and shock. Used
to initiate the detonation of more stable explosives. Example mercury
fulminate, lead azide etc.
ii) Secondary explosives: less sensitive than primary and require a
detonator to explode. More stable and safer to handle; Transport and
coal store. Example TNT tri-Nitro toluene, RDX cyclo- trimethylene-
trinitramine, PETN cyclo- Tetramethylenetetranitroamine.
iii) Tertiary explosives: very insensitive and require a booster charge to
initiate detonation. These are less explosives. For example, ANFO
ammonium nitrate fuel oil, slurry explosives etc.
3
Forensic
Chemistry -I
Explosives; Fire and Arson Investigation;
Forensic Analysis of petroleum Products
1
,Mrridhul Khajuria
Explosives: Introduction, Classification and chemistry of
explosives; Post blast investigation. Systematic examination
of explosive and explosion residues (organic and inorganic)
by colour test and TLC.
Introduction to Fires &Arson Investigation: Introduction to
Thermodynamics and Chemistry of Fire, Investigation of Fire
and Arson, Forensic Analysis of Fire Debris by Instrumental
methods.
Forensic Analysis of Petroleum Products: Introduction to
Petroleum Products and Analysis of Petrol, Kerosene and
Diesel as per BIS Specifications.
2
, Mrridhul Khajuria
Explosives:
These are materials that release a large amount of energy rapidly when
subjected to a specific trigger such as heat, pressure or shock. This energy is
often in the form of violent expansion of gases creating an explosion.
Characteristics:
1. Rapid decomposition: they undergo rapid chemical reactions; converting
solids or liquid substances into gases almost instantaneously.
2. Exothermal reactions: the decomposition Of explosive is highly
exothermic releasing a large amount of heat.
3. Gas generation: a large volume of gas is produced deceiving the
explosion which contributes to the high pressure and shockwave.
4. Pressure and shockwave: the rapid expansion of gases generates high
pressure and a shockwave, which can cause damage to the
surroundings.
Classification of explosives:
1. Based on velocity:
i) low explosives: deflagrate rather than detonate meaning they burn
rapidly but without a supersonic shockwave. the reaction is subsonic
and the explosive produce gas and heat at slower rate. Used in
propellants like gunpowder fireworks etc. Examples black less
powder, smokeless powder.
ii) High explosives: detonate with supersonic shock waves traveling
through the material. The reaction is rapid and violent producing a
powerful shockwave. Used in military mining and demolition.
Examples TNT- tri-Nitro toluene, nitroglycerin etc.
2. Based on sensitivity:
i) Primary explosives: highly sensitive to heat friction and shock. Used
to initiate the detonation of more stable explosives. Example mercury
fulminate, lead azide etc.
ii) Secondary explosives: less sensitive than primary and require a
detonator to explode. More stable and safer to handle; Transport and
coal store. Example TNT tri-Nitro toluene, RDX cyclo- trimethylene-
trinitramine, PETN cyclo- Tetramethylenetetranitroamine.
iii) Tertiary explosives: very insensitive and require a booster charge to
initiate detonation. These are less explosives. For example, ANFO
ammonium nitrate fuel oil, slurry explosives etc.
3
