Testing for Blood

[Voice]

Of course, one teacher needs to be able to check that a particular stain is blood and not vegemite in the Forensics Unit.. Does anyone out there do this? If so, what chemicals do you use other than leucomalachite green which is a carcinogen.
Can anyone help.
Thank you
Maree

[dime]

This might be quite dumb and just a thought, haven't tried it, but could you put some hydrogen peroxide on it? Should fizz if its blood, but I don't know about the vegemite.

[noona]

Hi Maree
I have a copy of what we use to make blood hope this helps
give me your fax no and I will fax it to you
Noona

[Voice]

Thanks Noona but I have plenty of recipes for making blood. What I seriously need is to be able to test 2 splotches on the floor and have one determined to be blood.
What can I do for that without using the chemicals mentioned earlier.
Maree

[noona]

I will ask the teachers here maybe they can help I will let you know

[rae]

What about ninhydrin it will test for aminoacids and isn't it what they use in CSI(LOL) when they swab an area they think may have blood and then use a little spray bottle of STUFF and in UV light it glows purple?

Lorrae

[Rowyrow]

Dont know if this will help


Leucomalachite green (LMG) color test: This chemical reagent has been around since the early part of the 20th century and undergoes a chemical interaction with blood, yielding a characteristic green color.
Tetramethylbenzidine (TMB) color test: At a crime scene, a CSI technician swabs a suspected bloodstain with a moistened Q-tip and then applies it to a Hemastix strip containing TMB. A Hemastix strip is a dip stick used to test for the presence of blood. If the Hemastix strip turns blue-green, it might be blood.
Kastle-Meyer color test: Phenolphthalein is the active chemical reagent in this particular test. When blood, hydrogen peroxide, and phenolphthalein are mixed together, a dark pink color results. This color change is due to the hemoglobin (the oxygen-containing molecule within red blood cells) causing a chemical reaction between hydrogen peroxide and phenolphthalein.

Other tests depend on chemical reactions that cause blood to fluoresce, or glow, under an ultraviolet light source, uncovering blood that is invisible to the naked eye. Offenders many times try to scrub walls and floors clean, mistakenly taking for granted that if blood is not visible, it can not be found. Fortunately, that is not the case. At the scene of a crime, blood can show up by spraying a fluorescent chemical over the area suspected of containing blood. The lights are dimmed, and ultraviolet light is passed over the area, causing bloodstains to fluoresce in the dark just like you see on CSI. Not only is the presence of blood established, but the area of blood distribution is also clearly indicated. This is where blood spurts, drag marks, spatter, footprints, and handprints show up.

The actors you see on CSI use fluorescent chemicals to get the blood to reveal itself. The most common fluorescent chemicals used are luminol and fluorescein.


Luminol--Luminol is highly sensitive and may reveal blood that is present in minute quantities. Luminol is able to expose blood in places that have been cleaned repeatedly unless a solvent such as bleach was used, and even on walls that have been painted to hide blood. In spite of the fact that it can negatively impact some serologic testing processes, luminol does not affect subsequent blood typing or DNA analysis.
Fluorescein--Fluorescein has been around since the early part of the 20th century. This compound does not interact with bleach the way luminol does. Fluorescein is better used over luminol for exposing bloodstains that have been cleaned up using solvents such as bleach. Fluorescein is advantageous in that it is thicker than luminol and drips less, therefore, sticks to vertical surfaces much better than luminol.

[Voice]

Thanks to all of you for your help. And Rowan, you have given me plenty of ideas.
Maree

[Voice]

Sorry, Rowann.
Maree

[smiley]

My very favourite store - the Professor Bunsen one - sells luminol in kits form that might be quite useful.

[Alison@Dunheved]

I just asked a science teacher and she said to spray a solution of luminol over the stain then look at it with a UV light. The stain which is blood will glow.