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Forensic chemistry

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carley rowan

on 15 October 2012

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Transcript of Forensic chemistry

Forensic Chemistry Fields of Chemistry Applications Without the use of science, criminals could not be convicted of their crimes.
Murderers would continue killing, thieves would continue stealing,
and drug traffickers would continue dealing.

Fortunately, in today's world, science is used in solving crimes.
Clues a criminal leaves behind can be traced to themselves through scientific evidence.
The range of uses of DNA analysis in forensic chemistry


Identification of a species (non-human) whose DNA
sample has beencollected from a crime scene.
This may either be evidence from a crime scene
or to positively identify a possibly fraudulent species e.g.
cheap fish is often replaced for very expensive varieties. Types of Forensic Chemistry Toxicology

Forensic toxicology deals with specimens for the presence of alcohol, drugs, and/or poisons. Investigations often involve driving-under-the-influence (DUI) of alcohol or drugs or death investigation. Toxicologists assist coroners and pathologists in determining the cause and manner of death (natural, accidental, suicide, or homicide). Trace Analysis/Arson

"Every contact leaves a trace”, the analysis of trace evidence plays a crucial role in crime scene investigation. The trace applications in forensic chemistry include the analysis of gunshot and primer residue, paint, hair, and fibers.


The electron microscope allows for quick analysis for tiny bits of hair and clothing. DNA Analysis


Forensic DNA analysis deals with the identification of the source of a body fluid through DNA testing.

DNA and body fluids are studied that might have value in the prosecution of a crime. Typical fluids are blood and saliva. Importance of Inorganic
Compounds Many inorganic compounds are analyzed as evidence by a forensic chemist. Analysis of the inorganic and organic compounds can offer a positive identification of timing.

Inorganic compounds are important as their composition is rarely altered by bacterial action or time. So a accurate time frame can be established. Examples of evidence that are composed of inorganic compounds include glass and soil Soil may be useful evidence in a wide variety of cases, for example: Soil is important when it has been moved, accidentally or deliberately, during criminal activity.
Soil samples can be taken to precisely locate where a crime might have taken place. Problems
Almost any technical and scientific technique
can be applied in forensic science.
Techniques can be classified as non-destructive
and destructive techniques.
The integrity of a sample in its original form is
paramount in a criminal trial. Much forensic evidence consists of very small
samples and sensitive analytical
techniques are required. All possible non-destructive techniques must be performed on a sample prior to the use of a destructive technique. Evidence Forensic entomology (use of bugs to determine time of death)

Forensic entomology will allow forensic chemists to be more precise
in their statements and determinations, particularly in the area of time of death. There are many different ways forensic chemists can find trace evidence, finger prints and preserve different samples Fuming Cabinet
Place an object inside, with superglue.
The glue sticks to the finger
prints making them visible. Cast
A way to preserve three dimensional impressions http://www.evsc.virginia.edu/~alm7d/soils/handouts/soil_minerals.pdf Soil is a common form of physical evidence found at the scene of crimes.
Soil from the crime scene may be picked up by a vehicle or found adhering to clothing or shoes. Soil may provide a clue linking a suspect to a particular crime site. GMCS
Stands for Gas Chromatography mass spectrometry, is capable of breaking
down and identifying complex compounds. UV lamp/light

uncovers body fluids such as blood that contain florescent particles Forensic science is the “application of science to those criminal and civil laws that are enforced by the police agencies in a criminal justice system” The job of the forensic chemist is to
identify materials and trace their origins.
Forensic science in its broadest definition,
is the application of science to law. The Job

Forensic chemists handle the evidence collected from the crime scene. Evidence may include hair samples, paint chips, glass fragments, or blood stains. Understanding the evidence requires tools from many disciplines. Throughout history,
evidence has been used to convict criminals
of the crimes that they have committed.
Today’s society has improved upon the methods of the past to bring
about more precise and accurate techniques. Bibliography http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP

http://halmapr.com/news/aquionics/emerging-trends-in-uv-disinfection/

http://hsc.csu.edu.au/chemistry/options/forensic/

http://www.forkparty.com/17529/how-forensic-science-solved-some-of-the-worlds-most-infamous-crimes

http://suite101.com/article/the-capture-of-ted-bundy-a50539

http://www.bluestar-forensic.com/gb/bluestar-chemistry.php The Experiment

There are many ways of developing fingerprints,
below is one experiment that uses iodine as a method of developing fingerprints.

1. Make a fingerprint on a small piece of filter paper by firmly pressing down.

2. Take a paper clip with a piece of string attached to it and clip this on to the filter paper. Place a few iodine crystals on the bottom of a screw top jar.

3. Hang the paper clip and filter paper inside the jar and put the lid on tightly trapping the string out the side of the jar and suspending the paperclip and filter paper.

3. After about ten minutes, the iodine will develop the print on the filter paper and the image should be clear enough to photograph.


Alternately, fingerprints can also be easily revealed by brushing
a fingerprinted surface with iron filings or lifting it from a
surface with adhesive tape - neither require 'developing'. Fingerprint Experiment How Forensic Science
has solved
infamous crimes. Forensics has been the deciding force behind the conviction of some of the world’s most notorious criminals. The Case

Theodore Robert Bundy (November 24, 1946 – January 24, 1989) was a gifted law student at one time, but became one of America's most feared men. He pretended to have a broken arm, which he used to convince women to help him carry books over to his car. Once at the vehicle, he would quite literally club them over the head and drag them away to be brutalized and ultimately murdered.
He’s thought to have murdered between 30 and 40 women. No fingerprints or physical evidence were found
at the crime scenes.
Yet there was a piece of evidence that
was to become a centre piece during the trial:
an odd bite mark on one of his victims. In the trial, the prosecution produced the photographic evidence of the bite marks and of Bundy’s teeth. They then proceeded to place an overlay of the bite mark on the photo of the teeth. This left no reasonable doubt that it was Bundy’s highly irregular teeth that left the impressions. The Trial Presented by Carley R and Angela A
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