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Luminol
Posted: 23 Aug 2006, 12:57
by Steph
Does anyone know of a reliable recipe and/or method for Luminol for the Year 12 HSC Chem, Forensic Science elective? It is used for detecting blood at crime scenes etc. I found one recipe using hydrogen peroxide, but have no method. Steph
Posted: 23 Aug 2006, 13:36
by juliem
Hi Steph
you could try where lesly worked /or ring her ( the teacher who wrote/co wrote the forensics course still is teaching there)
regards juliem
Luminol
Posted: 23 Aug 2006, 13:39
by Robbie
Hi Steph
Luminol is listed in Science Supply Aust P/L catalogue - 5 grams $68.60.
Toll Free Phone 1300 857 544.
Regards,
Robbie
luminol
Posted: 25 Aug 2006, 09:41
by m
Hi Steph
I too would like to know a method for luminol
looking forward to reading any suggestions
Luminol Preparation and Methods for Reactions
Posted: 26 Aug 2006, 23:04
by Robb
Hi All,
I will list the steps for preparing a Luminol Solution first, (particularly for those people seeing this for the first time), then move onto some Methods for you.
Luminol will only dissolve in solutions with a low pH. pH 11 - 14
Prepare the Luminol solution by dissolving 0.23 grams of luminol in 500 ml of 0.10 M Sodium Hydroxide solution. This give a very workable and basic solution for testing.
The Chemiluminescence will only last for a few seconds until the reaction is complete.
Keep in mind that over time Luminol will turn grey and the reactions involving it when it reaches this colour will not be as effective as fresh Luminol powder. Fresh Luminol should be an Olive green colour.
Methods for Preparing solutions:
(I will label each solution as a Luminol Solution and an Oxidising Solution. After you prepare each solution simply add them together as per each method)!
Method 1
Luminol Solution:
~ with Copper (II)
4g of Na[sub]2[/sub]CO[sub]3[/sub] (Sodium Carbonate)
0.2g of Luminol
24g NaHCO[sub]3[/sub] (Sodium Hydrogen Carbonate)
0.5g NH[sub]4[/sub]CO[sub]3[/sub].H[sub]2[/sub]0 (Ammonium Carbonate)
0.4g CuSO[sub]4[/sub].5H[sub]2[/sub]O (Copper Sulfate)
Dissolve all components in 1L of Distilled Water.
Oxidising Solution:
~with Peroxide
50.0mL of 30% H[sub]2[/sub]O[sub]2[/sub] (Hydrogen Peroxide)
Dilute this solution to 1L of Distilled Water
Mix Together!!
Emits light very bright, although the reaction is fast.
Method 2
Luminol Solution:
11g Na[sub]2[/sub]CO[sub]3[/sub] (Sodium Carbonate)
8g NaHCO[sub]3[/sub] (Sodium Hydrogen Carbonate)
0.2g Luminol
Dissolve all components in 1L of Distilled Water.
Oxidising Solution:
~with Cobalt (II)
Dissolve 0.1g Cobalt (II) Nitrate in 1L of Distilled Water.
Mix Together!!
This reaction is less bright but will last longer.
Method 3
Luminol Solution:
0.46g Luminol
4g NaOH (Sodium Hydroxide)
Oxidising Solution:
~with Bleach
Dilute 10mL of household bleach to 1L of Distilled Water.
Mix Together!!
This reaction lasts quite long and emits light brightly.
The solutions can be divided up to give repeated reactions, if you decide to do this make sure the quantities of each solution is added identically!!!
I hope this has added to your repertoire of Luminol Methods and Experimentation.
Have Fun!!
Robb……
Re: Luminol
Posted: 14 Aug 2009, 09:56
by rell
Hi Brains trust, i am using Luminol for the first time to detect blood for forensics topic.
I have read here how to make it up but do i add luminol and oxidising solution together
and then spray it on the area? Help
Narelle
Re: Luminol
Posted: 06 Nov 2012, 14:13
by RosalieM
I see your question wasn't answered, rell! A teacher here wants to play with some luminol (if I can get hold of some in time) and so that's why I'm searching here
Do the two solutions (luminol and oxidising solution) 'glow' when mixed together, or do you mix them together then spray on a blood sample to make them glow?
Re: Luminol
Posted: 06 Nov 2012, 14:17
by Robb
Hi All,
Don't add the oxidiser.... the Iron in blood will act as this, this is what produces the glowing Luminol.
Cheers,
Robb.....
Re: Luminol
Posted: 06 Nov 2012, 14:21
by RosalieM
so if we don't want to use blood, we use the oxidiser to make a glowing liquid that will impress everyone who comes to watch? Sorry I forgot to mention it's for an open night thing we have happening next week.
Re: Luminol
Posted: 07 Nov 2012, 09:54
by smiley
Best and easiest place is ProfBunsen. Comes in kit form & saves you having to buy bucket loads of chemicals.
Re: Luminol
Posted: 07 Nov 2012, 09:59
by Robb
Hi All,
Yes, then add the oxidiser to give the blue/green glow for that purpose.
Awesome....
Cheers,
Robb.....
Re: Luminol
Posted: 07 Nov 2012, 10:13
by kjt
A simple method of showing the chemiluminescence of Luminol is to use it with bleach. This reaction does not last as long as with an iron catalyst but is very easy and reliable! I used both this and a more complicated method with potassium ferricyanate to simulate blood.
Method from NCSU:
Materials:
Luminol Beaker or RB flask
Bleach Deionized water
1 M NaOH
Procedure:
Perform this demonstration in a dark lecture hall.
1. Make fresh solutions to guarantee longer periods of luminescence.
Solution A: Dissolve 0.05 g luminol in 100 mL of 1 M NaOH; Solution B:
0.5% NaClO (9 mL of commercial bleach in 91 mL water).
2. Chill both solutions in an ice bath. Darken the room and slowly pour the
two solutions together. When mixed, the solutions will produce a blue
glow. When the lights are turned back on, the solution is observed to be a
yellow/green color.
Re: Luminol
Posted: 07 Nov 2012, 14:33
by Robb
Hi All,
You have all great reactions that will do what is needed.
Take your pick and pretty much go from there. Safety first though.
Cheers,
Robb.....
Re: Luminol
Posted: 15 Jun 2020, 11:46
by Kathryn
Hi all. Does anyone know what the shelf life is of luminol (solid)?
Thanks
Re: Luminol
Posted: 15 Jun 2020, 12:02
by Merilyn1
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.
Re: Luminol
Posted: 16 Jun 2020, 09:50
by shellythenewlabby
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
Re: Luminol
Posted: 16 Jun 2020, 09:57
by Merilyn1
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).