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Eriochrome Black T

Posted: 06 Sep 2010, 13:24
by starfish
Hi everyone,

Can anyone tell me a recipe for making up Eriochrome Black T indicator for a water analysis prac? I don't have fancy stuff like triethanolamine or hydroxylamine hydrochloride in the recipes I've found so far, and I'm hoping there's a simple recipe that will work for these water hardness tests.

Thanks,
Kylie

Re: Eriochrome Black T

Posted: 06 Sep 2010, 13:59
by Robb
Hi All,

I prepare the solution by adding 0.2g of the dyestuff in 15mL of triethanolamine with the addition of 5mL of ethanol.

That will get you out of trouble.

Must be doing Metal determination.

Cheers,

Robb.....

Re: Eriochrome Black T

Posted: 06 Sep 2010, 15:18
by pkij
Recipe I have used from a Chemistry text book is;
Dissolve 0.2g powder in 15ml commercial NH3 and add 5ml ethanol. (I assumed commercial NH3 was conc. ammonia.)

This was for determination of water hardness using EDTA, it did work, however the solution does not keep for long. We could'nt work out why the prac was not working, I made up fresh solutions and yay it worked! :thumbup:

Re: Eriochrome Black T

Posted: 17 Jun 2011, 12:11
by Narelle01
its this time of year.....
thought i would get this thread up - just in case, someone else, like me is sratching her head working this prac out....

i need 80mls of this indicator.

You know when I am cooking at home, if i don't have something for a reciepe, i just leave it out, but i don't think thats going to work here....worse luck!

Re: Eriochrome Black T

Posted: 17 Jun 2011, 12:34
by Jazz
Eriochrome Black T Indicator
1% alcoholic: Dissolve 1 g of eriochrome
black T in 80 mL of 95% ethyl alcohol,
dilute to 100 mL with 95% ethyl alcohol.
(indicator for EDTA titrations)


http://www.flinnsci.com/Sections/Safety ... N_PREP.pdf

I think this link was posted before :-)

Re: Eriochrome Black T

Posted: 17 Jun 2011, 12:37
by Narelle01
is that correct Jazz?

Re: Eriochrome Black T

Posted: 17 Jun 2011, 13:20
by kjt
Hi,
We have used a salt/solid for several years now (and it keeps for years). The students just add a very small amount of solid to the solution instead of a prepared liquid indicator (which was a pain as it had to be fresh). We got the recipe from the internet and from memory it was:

1g Eriochrome T-Black and 100g sodium chloride crushed together.

(We only made up 20g, but even 10g would be plenty) Very simple and works a treat.

Cheers,
Kirsty

Re: Eriochrome Black T

Posted: 20 Jun 2011, 11:14
by Narelle01
it came up a very deep red - is that right?

Re: Eriochrome Black T

Posted: 20 Jun 2011, 13:27
by kjt
Our indicator/salt crushed solid is pale purple. When added to three water samples tested today, they started out a deep pink (almost cranberry) then went through purple to blue when titrated with EDTA (using method in Conquering Chemistry HSC).

Re: Eriochrome Black T

Posted: 20 Jun 2011, 14:45
by smeee
I have just made it up as per recipe in Chemistry Contexts :

Dissolve 0.5g of eriochrome black-T in an 80ml ethanol/20ml distilled water mixture.

It worked ok

Re: Eriochrome Black T

Posted: 21 Jun 2011, 09:10
by Narelle01
I used the recipe above, it took ages to dissolve and the colour deepened over night -oh well the prac is on now, while i recover from mixing the sodium iodide solution without a fume cupboard.

Re: Eriochrome Black T

Posted: 21 Jun 2011, 09:16
by Jazz
To be honest this is first time I made it 8-[ . No one complained It must be working. It has to be fresh though.I use recepies from this website and never had any problems

Re: Eriochrome Black T

Posted: 29 Jul 2020, 12:56
by mtg
Is there a substitute for Eriochrome Black T. I don't think I have it.

Re: Eriochrome Black T

Posted: 30 Jul 2020, 08:37
by Westlab - Alice
If it helps, we sell EL024-25G Eriochrome Black T LR. This is a 25g bottle. CAS: 1787-61-7

Re: Eriochrome Black T

Posted: 05 Aug 2020, 14:59
by mtg
Thanks Alice, I'll put it on my list for our next order.

Re: Eriochrome Black T

Posted: 06 Aug 2020, 14:04
by Westlab - Alice
mtg wrote: 05 Aug 2020, 14:59 Thanks Alice, I'll put it on my list for our next order.
Look forward to it :D