How test for urine residue

[pippo]

People,

 

Have a piece of laminate wood flooring, was soaked with something- not sure. I suspect urine from dogs, or recent rain deluge seeping into the house (?). I strongly suspect pet urine from tenant. Any way for me to get sample of wood scrap, and test for urine residue? Creatinine? Amines? Tips /advice greatly appreciated.

[Phi for All]

The UV from a black light will cause body fluids like urine, semen and blood to fluoresce. There are many other things that also show up under a black light, like antifreeze and some detergents, but you could find a list and eliminate the ones that wouldn't apply.

[pippo]

Hmmm, like a regular black light incandescent bulb from home depot? I have one. .........

[Phi for All]

That should work. If it doesn't glow, it's not a body fluid. If it does glow, it MAY be body fluids, but could also be something else that reacts to the UV light.

[John Cuthber]

For reasons unlikely to ever become clear, I researched this a while ago.

The answer is to look for urea.The simplest way is to use urease to convert the urea to ammonia and measure that.

There are details in this book

http://books.google.co.uk/books?id=Rot4VXFa27IC&q=urease#search_anchor

[pippo]

Woahhhhhh, John- good tip! (I'll have to purchase this bokk, I guess, or try inter library loan(?)) I can do that and test for ammonia easy in my lab! Unless, say, its sooo low in ppm, that is. I can test as ammonium hydroxide (ammonia in aqueous solution, of course). Again, if less than say, 100ppm, may not be detactable by titration.

Got to first do the uv light test. Then, go from there.

found this-

 

http://www.freepatentsonline.com/5827490.html

 

but seems to difficult for a basic lab like mine. Gotta heat to 650 deg??? Way out of my league. Not sure if this method wouldbe in that book, John.

Edited July 14, 2013 by pippo

[John Cuthber]

http://en.wikipedia.org/wiki/Urease

[pippo]

thanks. I will advise as to what happens with this detective effort

[ewmon]

People,

 

Have a piece of laminate wood flooring, was soaked with something- not sure. I suspect urine from dogs, or recent rain deluge seeping into the house (?). I strongly suspect pet urine from tenant. Any way for me to get sample of wood scrap, and test for urine residue? Creatinine? Amines? Tips /advice greatly appreciated.

 

We assayed creatinine in samples in a forensic lab to determine if the samples were urine. If the creatinine levels were too low (or zero), we concluded that the samples were not urine. Substances that failed the "urine" test were then assayed "olfactorily" by humans, as it were , to try to determine their nature, and we made a few conclusions, namely, apple juice and pickle juice were the most common counterfeits used. Forensically, we could not use urea because the kidneys can re-absorb urea from urine, but kidneys cannot re-absorb creatinine, leaving creatinine to be the more reliable marker.

 

In your case, other factors apply, such as the inorganic production of urea (as a wild guess, perhaps acidic rainwater percolating through UFFI, Urea-Formaldehyde Foam Insulation — who knows, right?), and also would any marker decay over time or exposed to wood flooring etc? FYI, ancient scientists thought that urea was solely the product of biological processes (so they would collect urine from farm animals for lab use) until the early 1800s when someone produced urea in the lab using inorganic materials.

 

But how much solution do you use to produce a sample? That is, what dilution do you want your sample to be? I don't know, but if you use this method, use distilled water. As for testing your sample, a drug-testing lab should do, just make sure they assay creatinine to test for the urine-ness of their samples (which they probably do). Who knows, you might also find the dogs were also gobbling up discarded roaches.

 

PS — Drug-testing labs typically test for aldehydes as they are used as an adulterant to ruin the drug tests. So, if your sample tests positive for creatinine and aldehydes, then my crazy UFFI theory would hold some water (no pun intended ). Personally, I like the blacklight test, as it is simple, cheap, repeatable, and reproducible and you only really need to test for organic substances — whether it was urine from pets or bodily fluids from slaughtering chickens in the kitchen doesn't really matter, does it?

[John Cuthber]

Good point about urea from other sources.

The problem with the UV is that it will also light up some plant based materials (chlorophyll and carotenes fluoresce too, Come to think of it, so do some rocks). Equally, it won't distinguish bird droppings being washed through from the roof.

Creatinine is a reasonable choice, but it's not trivial to test for.

[pippo]

More good tip. Thnaks, people. Oh- so far, I havnt been able to get into that house. man, how can i contrive an excuse for that........Hope creatinine has a decent "half life".