Author Topic: Stability of a HAuCl4 solution  (Read 13007 times)

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #30 on: December 13, 2014, 03:59:10 PM »
To make small particles from big ones is almost impossible, at least I don't know a way.

All the methods of making nanoparticles first start by dissolving the base material to make single atoms and then let them recombine until the capping agent prevents further agglomeration.

The capping agent ultimately determines the size of the resultant particles by stopping the growth.

So to make small particles from big ones, you would have to reoxidize the nanoparticles back to ions. 

Either you had insufficient herbals, or they just aren't strong enough as capping agents.

BTW, I have made a lot of violet and blue gold in the past :)  For this reason, I only make tiny batches when I am experimenting.
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LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #31 on: December 13, 2014, 04:15:24 PM »
Yeah, something went wrong thats for sure. There is also many big particles floating around. How important is temperature when adding reducing agent to the gold ions? This could have been an error, since the water was not close to boiling temperature, it was probably more around 30-40 degrees celsius

LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #32 on: December 13, 2014, 04:17:10 PM »
Capping agent should be strong enough, since the paper who used this method managed to get a red solution, and I'm pretty sure I used excess of the amount of ginger they used, but maybe their extract was stronger. But the error might be with temperature?

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #33 on: December 13, 2014, 04:33:43 PM »
Definitely go hotter, slow boil. 
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LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #34 on: December 13, 2014, 04:43:42 PM »
Do you know what the big particles floating around might be?

LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #35 on: December 13, 2014, 04:45:10 PM »
Where can I find the sodium citrate method? Is there a recipe in this forum?

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #36 on: December 13, 2014, 04:49:54 PM »
1 Liter of distilled water
300 mg TriSodium Citrate
4 ml of 1% gold chloride from SaltLakeMetals or enough gold chloride to contain 40 mg of pure gold.

Mix water and gold chloride
Heat liquid to boiling
Add citrate
Boil until color changes to ruby red.... 50 to 10 minutes
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LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #37 on: December 13, 2014, 05:00:40 PM »
Thanks Kephra. That sounds easy, I'll try that. I need a successful batch before experimenting further :)

LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #38 on: December 13, 2014, 05:04:38 PM »
Do you think that it would help to add a stabilizer/capping agent, such as a herb, after this citrate method has turned it in to ruby red, or should it be added at the same time as citrate?

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #39 on: December 13, 2014, 05:09:33 PM »
Leave it out, especially for your first batch.  You need to know what its supposed to look like, and adding other things might confuse the issue.
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Offline RickinWI

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Re: Stability of a HAuCl4 solution
« Reply #40 on: December 13, 2014, 06:08:39 PM »
I am thinking that this thread could be confusing to many since earlier in the thread we were talking about 2 different bases or electrolytes (Na2CO3 & NaOH) in relation to their usefulness in producing 2 completely different products (colloidal gold & Colloidal Silver).

So let me try to summarize the info & conclusions that appear to be correct:

First colloidal gold (Colloidal Gold): Since NaOH (sodium hydroxide) does a better job of raising pH for the Maltodextrin (or Karo) to be able to reduce the gold chloride into colloidal gold, then less NaOH would be required as compared to Na2CO3 (sodium carbonate). However, the end product (colloidal gold) would be the same as long as you had a sufficient amount of either to do the job of raising the pH into the correct range for the reducer (Maltodextrin or Karo) to work.

If one were to substitute NaOH (to replace the Na2CO3) into the following formula for making colloidal gold using the chemical reduction method, how much NaOH (1 Molar) would be the correct amount to use?

250 ml. DW
1  ml. Gold Chloride solution (20 drops)
0.5 ml. Na2CO3 (10 drops sodium carbonate) (1 Molar)
0.5 teaspoon Maltodextrin (a touch over 1 gram)

OR would you still use the same amount? (10 drops of NaOH)?

Colloidal Silver (Colloidal Silver): If protection against silver plating onto the cathode is the determining factor then Na2CO3 provides twice the protection (drop for drop of 1 Molar solutions of each.)

If any of my conclusions are erroneous please correct.

@LionHeart: 2 thoughts:

It might be useful for you to make 1 batch of colloidal gold using Maltodextrin as the reducer/stabilizer just so you have a point of reference.

When experimenting with the herbs as reducers, if you try something and obtain poor results then you might want to try the exact same experiment but with the other alkalizing agent (NaOH or Na2CO3) to see if it improves or worsens your results. (Tiny batches of course)

Assuming the herbs/herb extracts do work as reducing/stabilizing agents then I think your challenge is to find the pH at which each different herb performs the best. I would guess that all would perform best at or very near boiling so I would think that you could eliminate temp as a variable when designing your experiments. (not sure about that though -- just a guess)

Just curious: What benefits are you trying to achieve by using herbs rather than Maltodextrin?
So many VARIABLES & so little TIME.

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #41 on: December 13, 2014, 06:28:59 PM »
Quote
250 ml. DW
1  ml. Gold Chloride solution (20 drops)
0.5 ml. Na2CO3 (10 drops sodium carbonate) (1 Molar)
0.5 teaspoon Maltodextrin (a touch over 1 gram)
That's the formula I use every day to make mine, except I double it to make extra for my wife.

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LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #42 on: December 15, 2014, 05:18:27 PM »
I have succeeded in getting a nice ruby red colloidal gold with the citrate recipe, and what a sweet taste of victory. Thanks Kephra.

However, I'm determined to experiment more with the herbs also, with tiny batches though. Thanks for your inputs RickinWI, maybe its a good idea to vary pH conditions and see how it affects production. A big hurdle for me seems to be the difficulty in properly assessing the color, since the herb mixes its own color into the solution, so it makes it kinda difficult to know if its a success or not.

RickinWI, I'm interested in using herbs since i believe that there might be great therapeutic potential in mixing mineral and herbal chemistry. Both ancient chinese, ayurvedic and western alchemy and medicine made potions with herbs and gold, as well as other noble elements, although it's difficult to find out exactly what they did, it seems that they were indeed mixing these things. Today, modern nanotechnology are also mixing nanoparticles of gold, silver or platinum, with herbs, or simply herbal substances such as bioactive polyphenols, for various reasons. One is that the nanoparticles can function as a delivery system for the active substance, since many polyphenols have low bioavailibilty and can be metabolized before reaching desired destination such as a tumor for example. Attaching them to nanoparticles can increase their bioavailibilty and increase the odds of getting to the proper tissues in the body. It is also very likely that some herbal substances a very good stabilizers, ginger is supposed to be a much better stabilizer than citrate. In a study I read, they compared ginger reduced with citrate reduced colloidal gold and tested the particles in physiological conditions, i.e. pH 7,4, and found that citrate reduced particles aggregated much more than ginger reduced. So I'm just very curious about mixing the world of plant chemistry with the metal / mineral chemistry, and since it has a long history of use and experimentation, as well as a re-emering interest in modern science, I think its worth diving into.

Offline kephra

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Re: Stability of a HAuCl4 solution
« Reply #43 on: December 15, 2014, 06:02:16 PM »
I have succeeded in getting a nice ruby red colloidal gold with the citrate recipe, and what a sweet taste of victory. Thanks Kephra.
...
A big hurdle for me seems to be the difficulty in properly assessing the color, since the herb mixes its own color into the solution, so it makes it kinda difficult to know if its a success or not.
...
The earliest actual formula for colloidal gold I could find dated to the 1600s.  It was made by dissolving gold in aqua regia, and then placing a piece of pure tin in the solution.  Any metal except platinum will reduce gold, and it will be uncapped.  You might try that method, and then capping the particles with your herbal decoction.  That way you will be able to judge the nanoparticles first.  I have not tried the method, but historical records indicated it made ruby red colloid.

The ancient chinese and indian method create colloidal gold by communition, and the herbs were used to keep the gold particles apart while the grinding process was being done.  This method took months of work.  I don't know what the exact herbs used were.

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LionHeart

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Re: Stability of a HAuCl4 solution
« Reply #44 on: December 15, 2014, 10:17:17 PM »
Interesting. So I can obtain a red colloidal gold by placing solid tin in the HAuCl4 solution? And then the herbs can cap it afterwards. How do the tin catalyze formation of small (ruby red) particles without capping. Isn't it so that a capping agent is necessary to avoid large (blue) particles?