I never worried or wondered about cat pee. However, in other cases bleach and a few other things were discussed as lighting up the room when luminol was used. I just hoped you might have a link for that statement, but if not, I can/will research it further for myself. Thx.
I'm sorry. I missed this yesterday. I apologize if I misunderstood what you were asking, Trident. The post I quoted provided a link to an article which said that substances other than blood will react with luminol. I responded by saying that would fool the eye, but lab analysis would identify the source. In other words, if an investigator swabs an area of a crime scene that glowed under luminol, an analysis of that swab will distinguish between blood or some other substance. I didn't think that required a link because it's so obvious. But, the article actually says the same.
Therefore Luminol is not suitable for use at a scene where it is suspected that bleach has been used to clean the scene, and any positive result must be taken as a presumptive positive and
followed up by analytical tests to confirm the presence of blood.
http://the-gist.org/2011/03/seeing-red-–-presumptive-tests-for-blood/
According to this article, testing might take place even before a sample is collected.
The light, or luminescence, emitted in the luminol reaction is thought to result when an oxidizing agent, such as blood, catalyzes the oxidation of luminol by hydrogen peroxide in a basic solution. The reaction is not specific to blood, however, as other oxidizing agents such as sodium hypoclorite (bleach), certain metals, and plant peroxidases may also cause luminescence with luminol.
Because the reaction is not specific to blood, a follow up presumptive test, such as phenolphthalein, is typically run on potential samples prior to collection.
https://dps.mn.gov/divisions/bca/bc...es/forensic-programs-crime-scene-luminol.aspx
So, blue glow from luminol always equals blood, right? Wrong! Unfortunately, there are several other substances that are capable of catalysing the oxidation of luminol. It can also be oxidised by the chemicals in bleach, such as sodium chlorate; low levels of blood in urine can also trigger the reaction. Additionally, enzymes can also lend a hand. Peroxidase enzymes found in faeces can set off the chemiluminescence, and, more strangely, horseradish also contains peroxidase enzymes that can cause a false positive. Admittedly, the likelihood of a crime scene having been smeared in horseradish is pretty low, but it illustrates some of the drawbacks of relying on luminol as a clear-cut indicator of the presence of blood.
http://www.compoundchem.com/2014/10/17/luminol/
I don't know the year of this paper, but it's definitely worth a read.
Luminol and the Crime Scene
Robert Grispino, FBI Serology Unit