Introduction
Technology today
is advancing which evolves every field of science and one particular field is
Forensic Chemistry. Within each and every crime scene, there is a possibility
for identification of fingerprints, blood, and or drugs. Forensic Chemistry
is the application of chemistry to law enforcement. For example, one option to
analyze a crime scene is to reveal what chemical changes occurred at the event
to help investigators reconstruct the scene of the crime. This blog will be
limited to three focuses in which I will examine the application of forensic
chemistry to analyze fingerprints, blood, and drugs.
Fingerprints
One of the most well known examples of forensic chemistry
is known as DNA
fingerprinting. The topic overlaps one of my previous blogs called DNA
Profiling and can be read for more depth. According to DNA fingerprinting,
"Genetic fingerprinting allows for positive identification, not only of
body remains, but also of suspects in custody" (1). It is accomplished by
digesting the DNA from small samples of body tissue by using a series of
enzymes known as restriction
enzymes, also as seen in figure 1 below. Each individual has their own set
of DNA and while they may be unique, they can be falsely matched to a wrongly
accused individual. According to "Forensic Chemistry":
Because these digestions of DNA are particular to an individual, they are known as DNA fingerprints. Different combinations of enzymes produce different restriction patterns and the likelihood of a match between the test DNA and an individual differs. The reliability of each match is given as a statistical likelihood, because too few DNA fingerprint tests have been carried out to give the chances of a false match with certainty. Certain patterns are specific to ethnic groups. With most DNA fingerprint tests, the odds against a random match are several million to one. This is usually taken as a strong indicator that the person with DNA matching that from a crime scene is the culprit (Forensic 1).
This is one of the many
uses of forensic chemistry at its finest.
Figure 1: Image of
restriction enzymes and it combining into a new banding pattern (Restriction 1).
Blood
One of the first
few examples of forensic chemistry was the application of blood type tests to
crime scenes and evidence. Unlike DNA fingerprinting, blood is a crude approach
to making conclusions in crimes. They are used mainly for ruling out suspects.
According to "Forensic Chemistry", "Differences in proteins
allow blood to be classified into different categories. The simplest and most widely
known is the blood group system where two different proteins, Type A and Type
B, can be present in the blood. An individual may be type A, B, AB, or O (when
neither protein is present)" (1). Blood is one of the earliest, yet
weakest, forms of forensic chemistry in means of crimes and investigation.
Drugs
Through chemical tests, forensic scientists can identify
the presence of drugs or poisons. According to "Forensic Chemistry",
"These tests are basically a form of qualitative analysis, which
determines the types but not the amounts of potential toxins that may be
present" (1). Scientists can proceed to screening tests where they can
identify the drugs. Forensic chemistry overlaps with the specialty of forensic
toxicology and can be seen in a previous blog of mine with much more depth
called Forensic
Toxicology.
Conclusion
Many subfields of forensic science intertwine with each
other and can positively affect each other and help significantly. Forensic
chemistry can be seen as a classification of techniques in the science. All of
forensic science are geared to have the same goal, in which science is applied
to investigate criminal law. The application of forensic chemistry in criminal
law only strengthens the chances of succession during crimes through means of
chemical analysis.
Works
Cited
"DNA
fingerprinting." The Gale Encyclopedia of Science. Ed. K. Lee
Lerner and Brenda Wilmoth Lerner. 4th ed. Detroit: Gale, 2008. Science In
Context. Web. 10 Apr. 2013.
"Forensic
Chemistry." World of Chemistry. Gale, 2006. Science In Context.
Web. 10 Apr. 2013.
"Restriction
Enzyme." Restriction Enzyme Action of EcoRI. Accessexcellence.org,
n.d. Web. 10 Apr. 2013.
Again, and again, and again, you have just outdone yourself with such a comprehensive text on another aspect of forensic science. I am learning so much from reading your posts each week.
ReplyDeleteMy little request/quibble would only be to reconsider linking to Wikipedia for academic purposes. And you do such a good job of generally making sure your definition or quoting is phrased in your own way. But the definition in paragraph 1 is too close to the hyperlink, so consider rephrasing or just quoting.
I also would have loved to have seen a connection or layering to an actual case in which the FBI used forensic chemistry to solve a specific crime. Readers would see "proof" of its value that way.
Eric this is a tremendous blog. It was very captivating and sparked my interest in the field. I like how detailed you are in the post as well as how every explanation is clear and focused. It was a great idea to add links to the photos in order to emphasize your post. It really adds to it and draws more attention. The post is clearly organized and written in good format.
ReplyDelete