Luminol and Blue Star
Post on 06-Jan-2016
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DESCRIPTIONLuminol and Blue Star. Odalis Arellano, Ashanty Barrios, Ken Lin, and Giovanni Delgado. What Are They?. Blue Star and Luminol are chemicals used to detect trace amounts of blood left at a crime scene. They were designed to pick up the smallest amount of blood. - PowerPoint PPT Presentation
Luminol and Blue StarOdalis Arellano, Ashanty Barrios, Ken Lin, and Giovanni Delgado.
What Are They?Blue Star and Luminol are chemicals used to detect trace amounts of blood left at a crime scene. They were designed to pick up the smallest amount of blood. The tests can still detect blood even when it has been tampered with.
LuminolIn the Luminol test, bloodstains are made visible in total darkness by a blue lightLuminol powder is mixed with hydrogen peroxideand hydroxideThe iron found on hemoglobin in the blood is the catalyst in the oxidation reaction with the Luminol solution. This excites the electrons causing the blue glow that only lasts about 30 seconds.
Blue StarBlue Star is similar to Luminol It does not alter the DNA of the blood it is testing. It allows genotyping. With Blue Star, small traces at about1:10,000 dilutions can be detected, even if they were washed with detergent. Pictures can still be taken without the need of total darkness unlike Luminol.It is a newer test that is found in pill form.
Strengths and Weaknesses of LuminolLuminol chemiluminescence can be triggered by chemicals like copper or copper-containing chemical compounds, and even some types of bleach, this means that if an area was thoroughly cleaned with bleach and was then tested with Luminol, you would obtain the blue glow.
Luminol can also detect small amounts of blood in urine
Luminol wont work properly if the blood its tested on is animal blood.
Luminol can react with animal droppings (aka animal poop) causing the same glow as if it were blood. Luminol's presence can prevent other tests from being performed on a specific test area. Experts have been able to extract some DNA however, from samples tested with Luminol. The glow lasts only about 30 seconds.
Strengths and Weaknesses of Blue StarBlue Star is one of the more sensitive tests for blood stains and can detect smaller amounts of blood.
Any blood stains appear immediately because they react with the Blue Star.
It doesnt matter how much blood is present, in order for Blue Star to work, the blood just has to BE there.
Blue Star produces a much more intense and longer-lasting blue light that does not need total darkness to be visible.
This chemical has actually been used on crime scenes even though its relatively new.
Major Cases Using These ChemicalsIn a cold case from 1992, Blue Star was used to find the location of a man named Richard Woods. They found his body inside of his car but officials didnt believe that he was murdered there. Since he owned a furniture store, they tested it and found astounding results in the stores office.
Steve Mccausland and investigators found blood that belonged to 21 month old Ayla, in a house where they were reported to be missing. The investigators used Luminol and found the blue glow in the families basement. Since they only had one chance to test that area (the reaction could not be replicated on areas already tested) and they did not have much evidence to prove the girl was abducted or murdered, the case went cold. Officials have yet to find any more evidence that could lead to the uncovering of her murder.
Several Brief CasesA man claimed that he did not hear his friend get murdered during a sleep over. Police sprayed his arms and they turned blue. They spayed the sink as well and it also turned blue. A pedestrian was shot and run over by a driver in a white car. The driver was later caught and Blue Star was used to test the car for blood. The driver was then arrested after the blood and the DNA found on the car matched the victim.
Review QuestionsWhat are some of the drawbacks of Luminol? What is Luminol and Blue Star used for?
What are the main differences between Luminol and Blue Star?
How long does the glow last and what color is it?
Why is Blue Star considered better than Luminol by some?