Category Archives: Forensic Chemistry


By @forensicfield

What are Explosives?

Explosives are chemical compounds or mixture of compounds which are suitably initiated by heat, shock, friction or ignition will undergo a rapid chemical decomposition.

Explosion occurs with the evolution of heat, flash, loud sound and explosion of gases producing blast.

Types of Explosion

Normally There Are Three Types Of Explosives :

  • Nuclear
  • Chemical
  • Mechanical

Nuclear Explosive

A nuclear explosive is an explosive device that derives its energy from nuclear reaction.

Almost all nuclear explosive devices that have been designed and produced are nuclear weapons intended for warfare.

Nuclear Explosive Are Of Two Types:

  • Fission – Splitting of nucleus of atoms.
  • Fusion – Joining together under great force the nuclei of atoms.

Mechanical Explosive

A mechanical explosive is one that depends on a physical reaction, such as overloading a container with compressed air.

Chemical Explosive

A chemical explosive is a compound or mixture which, upon the application of heat or shock, decomposes or rearranges with extreme rapidity, yielding much gas and heat.

Categories Of Explosives

Explosives are classified as LOW  or HIGH explosives according to their rates of burn.

Low Explosive

Low Explosive Is usually a mixture of a combustible substance and an oxidant that decomposes rapidly however they burn slower than a high explosive which has an extremely fast burn rate as opposed to most high explosives which are compound.

Normally, low explosives undergo deflagration at rates that vary from a few cm/sec to approx 400 m/sec.

Low explosive are normally used as a propellants. Such as gun powder , flares and illumination devices.

High Explosives

High explosive compounds detonates at rates ranging from 3, 000 to 9,000 meters/sec.

High explosives are subdivide into two classes on the basis of sensitivity :-

Primary Explosives

Primary Explosives are extremely sensitive to mechanical shock, friction an heat to which they will respond by burning rapidly or detonating.

ex- mercury fulminate, lead styphnate and lead azide.

Secondary Explosive

Secondary Explosive also known as base explosives. These types of explosive are extremely sensitive to shock, friction and heat.

They may burn when exposed to heat or flame in small, unconfined quantities, but detonation can occur.

Dynamite, TNT, RDX, PETN, HMX and others are examples of secondary explosives.

Composition of an Explosive

It may be composed of chemically pure compound. Such as nitroglycerine.

It may be mixture of oxidizer and a fuel, such as black powder.

-: Mixture Of An Oxidizer And A Fuel :-

  1. Black Powder – Potassium Nitrate(75%) + Charcoal (15%) + Sulphur(10%)
  2. Flash Powder – Fine Metal Powder (Usually Mg Or Aluminum). + Strong Oxidizer (Potassium Chlorate Or Perchlorate)
  3. Ammonal – Ammonium Nitrate + Aluminum Powder.
  4. Armstrong’s Mixture – Potassium Chlorate + Red Phosphorus (Sensitive Mix.) (Primary High Explosive).
  5. Sprengel Explosives– Strong Oxidizer + High Reactive Fuel (Chlorates + Nitroaromatics)

Chemically Pure Compound

  • Nitroglycerine – A highly unstable and sensitive liquid.
  • Acetone Peroxide – White Unstable Organic Peroxide.
  • TNT – Yellow Insensitive crystals
  • Nitrocellulose – A nitrated Polymer.
  • RDX, PETN, HMX – Very powerful explosives (used in pure or in plastic explosive).
  • C-4 – RDX Plastic Explosive.

What Is Chemical Explosive Reaction?

  • A chemical explosive is a compound or mixture which, upon the application of heat or shock, decomposes or rearranges with extreme rapidity, yielding much gas and heat.
  • For a chemical to be an explosive, it must exhibit all of the following:
  • Rapid expansion (rapid production of gases or rapid heating of surroundings)
  • Evolution of heat
  • Rapidity of reaction
  • Initiation of reaction.

Evolution Of Heat

The generation of heat in large quantities accompanies every explosive chemical reaction. Rapid liberation of heat that causes the gaseous products of reaction to expand and generate high pressures.  This rapid generation of high pressures of the released gas constitutes the explosion.

Rapidity Of Reaction

Rapidity of reaction distinguishes the explosive reaction from an ordinary combustion reaction by the great speed with which it takes place.

Initiation of Reaction

This reaction occurred after being initiated by the application of shock or heat to a small portion of the mass of the explosive material.

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By @forensicfield

What is Doping ?

Doping is defined as the occurrence of one or more of the following anti-doping rule violations.

  1. Presence of a prohibited substance in an athlete’s sample
  2. Use or attempted use of a prohibited substance or method.
  3. Refusing to submit to sample  after being noticed.
  4. Failure to file athlete whereabouts information & missed tests.
  5. Tampering with any part of the doping control process.
  6. Possession of a prohibited substance or method.
  7. Administering or attempting to administer a prohibited substance or method to a athlete
  8. Trafficking a prohibited substance or method

Why sports performers take drugs?

  • Better results lead to better sponsors and endorsement contracts
  • Desire to be the best at all costs; winning brings financial rewards
  • Making the most of a short sporting life
  • To recover from injury more quickly or to mask pain
  • Influenced by others
  • Desire to meet expectations of others
  • Natural ability isn’t good enough

History of Doping

  • Ancient Greeks ate plants to try to improve performance at the Olympic Games.
  • 1886: Fatality of an English cyclist using the stimulant trimethyl.
  • 1904 Olympic Games: Some American cyclists used strychnine.
  • 1976 Montreal Olympic Games dominated by East German women‘s swim team.

Historical Efforts to Stop Doping

  • 1983:    The USOC Drug Control program was established (widespread perception that the USOC was helping athletes beat testing programs).
  • 1950s:  IOC passed a resolution against doping.
  • 1967: IOC established a medical commission to control drug use.
  • 1988:    Summer Olympic Games in Seoul: Ben Johnson.’’


A drug is any chemical substance you take that affects the way your body works.

Most drugs are developed for medical purposes, but doping means taking drugs to improve sporting performance.

It is a growing problem in sport.

Classes of Banned Substances

  • Stimulants
  • Narcotics Analgesics
  • Diuretics
  • Anabolic-Androgenic Steroid
  • Beta-adrenergic blockers

Why are they banned?

  • Health Concerns – some drugs used by athletes can have serious effects on an individual’s health. e.g. Anabolic Steroids
  • Legal Concerns – some drugs are banned because they are illegal in general society. e.g. Cocaine
  • Ethical Concerns – The use of certain drugs which do not pose a major health risk, but may offer a performance advantage over other athletes. This may be considered cheating. e.g. Beta Blockers

Anabolic agents

Anabolic agents are the most commonly used drugs in sports. They mimic testosterone, a male hormone


  • Stanozolol
  • Clenbuterol
  • Boldenone
  • Nandrolone
  • Testosterone

Effects can include:

  • Increases muscle mass
  • Develops bone growth
  • Increases strength,
  • Rapid improvement
  • Increases aggression

Side-effects can include



Stimulants are the second most commonly used drugs in sports.

Examples of these drugs include: amphetamines, ephedrine, cocaine and caffeine.

Effects can include:

  • Reduces feelings of tiredness so a person can train for longer.
  • Stimulates the central nervous system (CNS) making people more alert

Side-effects can include:

  • User becomes irritable and is unable to sleep.
  • High blood pressure
  • Irregular and faster heartbeat.


Narcotic analgesics are addictive drugs & are usually injected into the blood stream. Ex: heroin, methadone, morphine & codeine.

Effects can include:

  • Reduces the sensation of the central nervous system.
  • Masks pain

Side-effects can include:

  • Loss Of Concentration
  • Loss Of Coordination


Diuretics are drugs which increase the rate of water loss from the body. Ex: Furosemide, Triamterene & Chlortalidone.

Effects can include

  • Diuretics are used in sports where there are weight categories to ‘make the weight’.
  • Speeds up work of kidneys by producing more urine. This reduces fluid retention, which causes rapid weight loss.

Side-effects can include:

  • Dehydration and possibly dizziness.
  • Headaches, nausea & fatigue.
  • Kidney illness can develop.
  • Muscle cramps.


Beta-blockers are used as a relaxant.

Examples– atenolol and nodolol.

Side effect

However, they can reduce the heart rate so much that there is a danger that the heart may stop.

Effects of Substances -BLOOD DOPING

  • A procedure which involves injecting extra blood, red blood cells, artificial oxygen carriers and related blood products into the body as a means of increasing the oxygen carrying capacity of the blood.
  • Flaws in technique can lead to complications ranging from bacterial infections to fatal reactions.
  • The sharing of needles or blood can lead to diseases such as hepatitis or HIV.

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