MadSci Network: Chemistry

Re: If you test a surface with luminol, can you test the same surface again?

Date: Fri Sep 19 06:34:50 2008
Posted By: Dale L. Laux, Staff, Serology/DNA, Ohio Bureau of Criminal Identification
Area of science: Chemistry
ID: 1221765692.Ch

Hello Emily,

I have used luminol quite a lot in crime scene processing and wrote a chapter on luminol in 'Principles of Bloodstain Analysis' ISBN#0-8493-2014-3.

Luminol works best on surfaces such as carpeting. A smooth surface such as paper money might present some difficulties (luminol running off surface). If you let the bill dry and then re-apply the luminol, you will probably get a reaction but the stain may appear misshapen.

Luminol is difficult to work with. You must apply it in a completely darkened room and use a camera mounted on a tripod for a timed exposure. Here is a site that discusses a product called Bluestar and how it's used: http://www.bluestar- If you are good with a camera, you may try a technique called bounce flash. During the timed luminol exposure in the dark, hit the button on a camera flash that's aimed at the ceiling. The resulting picture may show the bill with the luminescence visible.

Remember that luminol is a presumptive reagent and that other things besides blood may give you a reaction.

Good luck with your project Emily.


Dale L. Laux
Forensic Scientist

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