Colloidal Silver and Gold Forum

Production Techniques and Chemistry => Colloidal Gold Production => Topic started by: mraluma415 on August 05, 2012, 12:52:49 AM

Title: The presence of Gold Chloride in Colloidal Gold after reduction..
Post by: mraluma415 on August 05, 2012, 12:52:49 AM
What is a good way to test a reduced colloidal gold batch for the presence of gold chloride. I would like to know for sure how much reducing agent to use based on this ability to confirm how much of the Gold Chloride has been converted? I have read of this on the forum before but cannot seem to find it.
Title: Re: The presence of Gold Chloride in Colloidal Gold after reduction..
Post by: kephra on August 05, 2012, 01:41:30 AM
The usual test (http://www.goldnscrap.com/index.php?option=com_content&view=article&id=63:stannous-chloride-test-for-gold-platinum-and-palladium-presence&catid=25:scrap-gold-9k-24k&Itemid=20) is to add stanous chloride to the sample and see if you get a purple reaction.  However, I doubt the test works if you have stabilizers and lots of nanoparticles present.  That's why I use such a high proportion of reducing agents to gold chloride.  Leftover ionic gold is only possible if there is not enough reducing agent present.
Title: Re: The presence of Gold Chloride in Colloidal Gold after reduction..
Post by: mraluma415 on August 05, 2012, 02:12:11 AM
I see. So the Stannous Chloride only reacts with gold chloride and not gold nanoparticles, yet if too saturated may pick up on the nano particles as well? If the excess stabilizers can be filtered out with millipore filters and the electron bond holds stability, then more stabilizer is always a plus!
Title: Re: The presence of Gold Chloride in Colloidal Gold after reduction..
Post by: kephra on August 05, 2012, 02:19:10 AM
The color of the gold nanoparticles will hide the possible color change from the tin chloride.