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Topic: Chloroauric acid concentration by Spect 20  (Read 5576 times)

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Offline Zetron

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Chloroauric acid concentration by Spect 20
« on: January 10, 2008, 11:13:37 PM »
Hello: I have a Spectronic 500 (I think) it is useful from the UV to some of the NIR. I want to quantifiy solutions of Chloroauric acid before attempting to make colloidial gold from them.

It would be very helpful if someone could tell me the frequency at which the Chloroauric acid solution will give me the most absorption? I think it would be in the red or violet regions of the chromatic spectrum, but I do not want to "tip toe" through Roy G Biv on a Spect 20 trying to find the extinction peaks.

I plan to make more Chloroauric acid using Canadian Maple Leaf gold, reagent grade Nitric and pool grade HCL. As before I will evaporate off the nitric acid. I have a Cl specific ion electrode and an Orion meter that I am going to use to determine chloride concentrations in the finial Gold colloid.

This is NOT a business, it is my own research. I worked as a Chemist for Magnaflux in the 70's and as a Technologist for Amoco til 1995.

Any comments would be helpful,

Thank you,

David

Offline ARGOS++

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Re: Chloroauric acid concentration by Spect 20
« Reply #1 on: January 11, 2008, 08:19:33 AM »

Dear Zetron;

All I was able to find during an extensive search was that the crystals are yellow till reddish yellow.
I saw also a picture of an aqueous solution that looks like a bright yellow what indicates that Lambdamax must lay close to 360 – 380 nm.

For more precision you have to measure it by your own, but take care that you have at least a small excess of HCl to be all time pH-stable!

I hope this is anyway of some help to you.


Good Luck!
                    ARGOS++


Offline Zetron

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Re: Chloroauric acid concentration by Spect 20
« Reply #2 on: January 11, 2008, 04:24:19 PM »
ARGOS: Thanks.

I had come across a WHO test write up for Methyl Bromide which used Chloroauric acid and was to be tested at 440nm against a water blank.

Because of the colloidial gold nanospheres giving SPR s in the red and NIR I was expecting to see a peak there for Chloroauric acid?

David

Offline Zetron

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Re: Chloroauric acid concentration by Spect 20
« Reply #3 on: January 11, 2008, 04:29:42 PM »
Hello again: I also was wondering where I might purchase a cuvette holder for my Bausch & Lombe Spectrophotometer 700? I have the large test tube holder and not the cuvette holder.

David

Offline ARGOS++

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Re: Chloroauric acid concentration by Spect 20
« Reply #4 on: January 11, 2008, 07:06:06 PM »

Dear Zetron;

This Question is quite hard to answer, because we don’t know your location.

But you may search for a supplier of Bausch & Lombe Instruments.
Several times also a second hand shop for Laboratory Instruments is a good (and cheap) source.
Or maybe another university owns more than one.

Good Luck!
                    ARGOS++


Offline Zetron

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Re: Chloroauric acid concentration by Spect 20
« Reply #5 on: January 11, 2008, 11:47:27 PM »
Thank you ARGOS++, FYI I am in Quartzsite Arizona at present. As I mentioned I am retired AND I am a fulltime RVer. I have MANY scientific PROJECTS some are best done while far away from the crowd and the "ELECTROSMOG 60 HERTZ RFI".

I usually look on Ebay for my equipment, but it is a slow time consumming process.

Thanks again

David

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