Luminol 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.

The tests can still detect blood even when it has been tampered with.

Luminol

In the Luminol test, bloodstains are made visible in total darkness by a blue light

Luminol powder is mixed with hydrogen peroxide and hydroxide

The 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.

Luminol

Blue Star

Blue 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 about 1:10,000

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.

Blue Star

Strengths and Weaknesses of Luminol

•Luminol 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 won’t work properly if the blood it’s 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 Star

Blue 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 doesn’t 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 it’s relatively new.

Major Cases Using These Chemicals

In 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 didn’t believe that he was murdered there. Since he owned a furniture store, they tested it and found “astounding” results in the store’s 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 area’s 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 Cases

A 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 Questions

What 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?

Bibliography

http://www.csigizmos.com/products/blooddetection/bluestar.html   http://chemistry.about.com/od/glowinthedarkprojects/a/

luminolblood.htm

  https://www.ncjrs.gov/App/Publications/abstract.aspx?ID=237268

http://www.bluestar-forensic.com/gb/bluestar-sensitivity.php

http://www.bluestar-forensic.com/gb/bluestar-dna.php