Role of
Forensic Chemistry
1.
Drugs in Forensic Chemistry
- Forensic drug analysis deals with the identification of
controlled substances.
- Drugs are classified into narcotics, stimulants,
depressants, hallucinogens, and designer drugs.
- The primary task is to confirm the presence of illegal
or misused drugs in samples.
- Drug evidence can be found in powders, tablets,
capsules, plant material, or biological fluids.
- Analytical techniques like GC-MS, HPLC, and IR
spectroscopy are commonly used.
- Chain of custody ensures proper handling and
admissibility in court.
- Drug profiling helps trace the origin or manufacturing
process.
- Both qualitative and quantitative analysis are
essential.
- Forensic drug chemistry provides objective scientific
evidence.
- It supports law enforcement in combating drug
trafficking and abuse.
2.
Toxicology
- Forensic toxicology studies the adverse effects of
chemicals on living organisms.
- It involves detecting and interpreting poisons, drugs,
and toxins in biological samples.
- Samples include blood, urine, hair, saliva, and tissue.
- Toxicologists identify the type and concentration of a
toxic substance.
- Knowledge of pharmacokinetics and pharmacodynamics is
essential.
- Analytical techniques such as LC-MS/MS and immunoassays
are widely applied.
- Toxicology can reveal accidental, suicidal, or
homicidal poisoning.
- Postmortem toxicology helps establish cause of death.
- Workplace and environmental toxicology monitor exposure
risks.
- The results provide critical evidence in both criminal
and civil cases.
3.
Explosives
- Forensic analysis of explosives deals with detection
and identification of explosive materials.
- Explosives can be classified as low (deflagrating) or
high (detonating).
- Common examples include TNT, RDX, PETN, and homemade
mixtures.
- Crime scenes often contain residues in debris,
clothing, or soil.
- Instrumental techniques like Ion Chromatography, GC-MS,
and SEM-EDS are used.
- Trace detection is crucial due to small sample sizes.
- Explosive investigations aid in counterterrorism and
criminal cases.
- Proper safety and handling protocols are mandatory in
analysis.
- Explosive signatures can help link suspects to devices.
- This field plays a vital role in national security and
public safety.
4.
Trace Evidence
- Trace evidence refers to small, often microscopic materials
transferred during a crime.
- Examples include hair, fibers, glass, paint, soil, and
gunshot residues.
- The Locard Exchange Principle forms
its foundation.
- Trace analysis can link suspects, victims, and crime
scenes.
- Microscopy is a primary tool in trace examinations.
- Spectroscopic techniques (FTIR, Raman) enhance
identification.
- Even minute particles can provide powerful evidence.
- Proper collection and preservation are critical.
- Comparison with known standards confirms identity.
- Trace evidence often serves as silent but decisive
proof in court.
The Locard Exchange
Principle is a cornerstone of forensic science, stating that "every
contact leaves a trace." This principle, formulated by Dr. Edmond Locard,
emphasizes that when two objects come into contact, they inevitably exchange
materials, such as:
1. Hair
2. Fibers
3. DNA
4.
Fingerprints
5. Soil
6. Dust
This
exchange of materials can be used to:
1. Link
suspects to crime scenes
2.
Identify individuals involved in a crime
3.
Reconstruct crime scenes
The Locard
Exchange Principle is fundamental to forensic investigations, enabling experts
to analyze evidence and piece together the events
surrounding a crime.
Example of
real case of solved on the basis of
Locard principle:
The 1984
cold case murder of Pia Rönnström in Sweden was solved using the Locard
Exchange Principle. A DNA sample was collected from the crime scene and matched
to a suspect years later. The DNA was found on a piece of clothing and compared
to the suspect's DNA profile. The match linked the suspect to the crime scene.
Investigators found fibers on the suspect's clothing that matched fibers from
the victim's clothing. The fibers and DNA evidence were crucial in convicting
the suspect. The case demonstrates the importance of trace evidence in solving
crimes. The Locard Exchange Principle played a key role in bringing justice to
the victim's family. The case was solved nearly 20 years after the crime was
committed. The DNA evidence was the key to cracking the case.
5.
Environmental Forensics
- Environmental forensics identifies sources of pollution
and contaminants.
- It combines chemistry, geology, and biology with legal
investigations.
- Typical contaminants include heavy metals,
hydrocarbons, pesticides, and industrial waste.
- Sampling involves soil, water, air, and biota.
- Stable isotope analysis can trace the origin of
pollutants.
- Environmental forensics helps resolve liability and
responsibility in contamination cases.
- It is applied in oil spills, groundwater contamination,
and hazardous waste cases.
- Both qualitative and quantitative methods are employed.
- The results guide environmental policy and legal
decisions.
- This field bridges science, law, and environmental
protection.
6.
Document Examination
- Forensic document examination analyzes the authenticity
of written materials.
- It includes handwriting analysis, signature
verification, and typewriting studies.
- Ink, paper, and printing processes are also examined.
- Alterations, erasures, and forgeries are common
concerns.
- Microscopy and spectral imaging reveal hidden details.
- Thin-layer chromatography helps identify ink types.
- Document examiners also study watermarks and security
features.
- Questioned documents often involve fraud, forgery, or
identity theft.
- Expert testimony from examiners carries weight in
court.
- This field protects against deception in both criminal
and civil cases.
