Australia's Science Forum

Merilyn1 wrote: ↑15 Jun 2020, 12:02 I don't know if there is any shelf life for luminol, especially in a school setting. Might be different if you're trying to track down an offender who is on the run!
Once made up, it has a very short shelf life of only about two hours. I have a good recipe for detecting blood if you need it.

Hi Merilyn1, Would I be able to get a copy of the recipe please as we sometimes have trouble with the luminol.

Thanks

Yeah, sure. It is from a reputable source (NSW Police Force Forensic Services). Recipe is for 250mL but I've usually just made up 50mL which has been plenty.

For ~250mL spray:
12.5g sodium carbonate
250mL distilled water
0.25g Luminol
20mL 6% hydrogen peroxide
Add sodium carbonate to water (expires two years from preparation)
Add luminol and hydrogen peroxide to the sodium carbonate solution (shelf life of only TWO HOURS)
It won't all quite dissolve but it still works fine.

You can make the sodium carbonate solution in bulk beforehand (I just measured out 250ml of this solution - it is a bit of bucket chemistry).