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Method for analysis Gold(III) using visible spectrophotometer

October 22, 2009

Dear Chemist,
Firstly, let me introduce my self. My name is Sofian Sauri. I am working in an environmental lab company.
I have questions from my friend for analysis Gold and silver, but with a simple visible spectrophotometric method. This option is being chosen because in my friend place there is only visible spectro and trying to avoid for buying a new instruments (Such as AAS, ICP etc) due to budget shortages.
I actually have found the method for those elements. I meant to use turbidimetric (As AgCl) for analysis Silver and this would not require expensive chemicals and instruments. But the problem is the interference from other matrix is still unknown and the effective condition of the precipitation still unknown.
For Gold, I will use method methiomeprazine hydrochloride (MMH), but the chemical seems hard to find in my country (Indonesia).
Therefore, is there any advice or suggestion or maybe another better method?
Thank you very much for your help.
Cheers,

Sofian Sauri
employee - Indonesia

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Looking at "Colorimetric Analysis of Metal Finishing & Metal Working Solutions and Effluents" by Aubrey Knowles There are methods that use 4-Dimethylaminobenzylidene-rhodanine, Rhodamine B, 4-(2-Pyridylazo)resorcinal disodium salt dihydrate, and hydrochloric acid.

Best of Luck

Regards

Ira Donovan, M.S.F.
Kansas City, Missouri
October 22, 2009

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It seems very interesting information provided by this page. I work in a laboratory. I'm also interested in analyzing spectroscopic gold. I'm using NHCl3, Rhodamine, HCl and ether to liberate gold from a solution. Can you provide information about subsequent spectroscopic analysis.

Thank you very much

Antonio Delgado, Chemical Engineer
- Peru
November 1, 2009

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The rhodamine B method uses HCl and ammonium chloride to form the red-violet complex which is extracted with benzene. Aqueous layer discarded. Organic layer analyzed at 565nm.

Best of luck.

Ira Donovan, M.S.F.
Kansas City, Missouri
November 2, 2009

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If you have an analytical balance, gravimetery is a better way to go for Au.

Either do an acid digestion, and weigh the Au directly, or plate the Au (after the addition of excess cyanide) out onto a Pt or Pt clad cathode, which you weigh before and after.

Dave Wichern
Consultant - The Bronx, New York
November 3, 2009