Author Topic: Success factors - keep the intended water volume and the heat  (Read 8180 times)

ShivaDestructor

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I just wanted to share a finding.

I've done numerous batches of colloidal gold using the Na2CO3/maltodextrine formula, and after adjusting the formula after my maltodextrine "strength", I can reproduce the results. I've started to scale up since I am going to give a few people at least a months supply of 20 mg gold daily - for 40 PPM that means 500 ml daily. One month for one person = 15 liters. That is not fun to do in 250 ml batches.

Anyway, my colloidal gold experiments started out with a few different purple batches, and then I hit a dark red one, and then I got the "perfect" red shade in a dozen experiments in a row. Suddenly when scaling up I got a purple one again.

I realized that I had been boiling off a lot of water while measuring chemicals, and I recognize that from earlier experiment - too little water = purple.

Another pattern I noticed was that I also got purple if I did not have a constant high temperature, i.e. boiling.

/J

Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #1 on: May 01, 2012, 02:44:06 PM »
I have made 250ppm colloidal gold using the same basic formula.

http://www.cgcsforum.org/index.php/topic,248.msg1880.html#msg1880

A sample I have kept since I wrote that post is still red, and hasn't precipitated.

I think it could go higher.  It would be great to get 10mg of gold into a tablespoon!

There is the unknown and the unknowable.  It's a wise man who knows the difference.

ShivaDestructor

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Re: Success factors - keep the intended water volume and the heat
« Reply #2 on: May 01, 2012, 06:50:11 PM »
I have made 250ppm colloidal gold using the same basic formula.

Ok, then my "dissipated water" theory does not seem to hold... water :).

I've noticed some other discrepancies - one batch is colorless after putting all substances in the water, another is slightly purple, a third deep purple, and a fourth pink! Same temperature, volume, measurements of additives and gold, and timing - yet great variety.

/J

Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #3 on: May 01, 2012, 07:15:14 PM »
When I do the same thing, I get the same results. 
Recently, I made quite a few 500ml batches at 50ppm for myself and my wife with dextrin.  Each batch turned out perfect.
I added the dextrin to cold water, brought it to a boil in my microwave oven.
Then I transferred it to my hotplate with mag stirrer.
When it started to boil again, I added 2.5 ml gold chloride.
Immediately, I added sodium hydroxide a drop at a time, approximated 1/2 second apart for a total of 40 drops.
Each drop of hydroxide immediately caused a color change in the vicinity where the drop landed, and with each drop it got deeper red.

So the question is, what is different that makes your results inconsistent?

I also made a batch with only the dextrin, and no pH increaser.  It took a long time, but eventually I got a nice red colloid.  The solution first turned a very dark purplish black, and after a while shifted to red.  The end result was a little darker and a little toward brown.  This was a surprise to me because dextrin alone is not supposed to be a good reducing agent.  I might have discarded it had I not been busy with something else.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

ShivaDestructor

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Re: Success factors - keep the intended water volume and the heat
« Reply #4 on: May 01, 2012, 07:47:52 PM »
When I do the same thing, I get the same results. 

Of course, it is a matter of tolerances. I don't know yet if 5% +/- Na2CO3 may be a source for the variety for instance - it is awfully easy to get 38 or 42 mg when aiming for 40. Every part of the process has steps with a certain error margin.

Quote
Immediately, I added sodium hydroxide a drop at a time, approximated 1/2 second apart for a total of 40 drops.
Each drop of hydroxide immediately caused a color change in the vicinity where the drop landed, and with each drop it got deeper red.

For instance, you wrote "Immediately". During my recent experiments it feels like a delay of 5 seconds from one batch compared to another between steps might visibly affect the result. The important thing though is that my END result comes out "identical" regardless of if it was a clear/light violet/dark purple/pink start - and it does (become red).

/J

Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #5 on: May 01, 2012, 08:19:33 PM »
Its the end result that matters.

I find the most critical measurement is the gold chloride because thats what determines the ppm but the amounts of dextrin/maltodextrin/carbonate aren't very critical.

As a matter of course, I don't even bother to weigh the dextrin or maltodextrin.  There is a minimum requirement, but doesn't seem to be a max.  I use a small spoon to measure the stabilizer in actual practice.  As to the carbonate or hydroxide, they don't seem to be that critical either except that I don't want the pH to be too high.    Sodium citrate and salt are less forgiving, so if I am working with them, then I weigh them as accurately as I can.

When I do the same thing, I get the same results. 

Of course, it is a matter of tolerances. I don't know yet if 5% +/- Na2CO3 may be a source for the variety for instance - it is awfully easy to get 38 or 42 mg when aiming for 40. Every part of the process has steps with a certain error margin.

Quote
Immediately, I added sodium hydroxide a drop at a time, approximated 1/2 second apart for a total of 40 drops.
Each drop of hydroxide immediately caused a color change in the vicinity where the drop landed, and with each drop it got deeper red.

For instance, you wrote "Immediately". During my recent experiments it feels like a delay of 5 seconds from one batch compared to another between steps might visibly affect the result. The important thing though is that my END result comes out "identical" regardless of if it was a clear/light violet/dark purple/pink start - and it does (become red).

/J
There is the unknown and the unknowable.  It's a wise man who knows the difference.

ShivaDestructor

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Re: Success factors - keep the intended water volume and the heat
« Reply #6 on: May 01, 2012, 08:39:14 PM »
As a matter of course, I don't even bother to weigh the dextrin or maltodextrin.  There is a minimum requirement, but doesn't seem to be a max.

Are you sure? You might remember that I wrote you in a PM that when I used the standard recepy with 125 mg maltodextrine/250 ml water, my solution turned instant deep purple BEFORE I added the Na2CO3.

That batch never turned red even after adding the Na2CO3.

It seems that there are two purples - the nanorod purple and the 80 nm (or what it is) purple.

In the recently linked Czech research presentation they had a table with different sugars/different particle size.
25 nm = maltose
35 nm = lactose
44 nm = glucose
50 nm = galactose

Since maltodextrine is a mix of different carbohydrate chain lengths, could it be that a certain sugar/length is quicker to reduce? When I use 60 mg maltodextrine the result is first lighly violet then red, when I used 120 mg maltodextrine it was instantly deep purple and never recovered (it is only one sample but I really don't feel like wasting gold at the moment or time - I'll investigate that later, in small doses and different concentrations).

It FELT like the maltodextrine "overdose" was "violent" - that it instantly produced fat particles, instead of gently, slowly reducing the gold and building up tiny particles.

/J




Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #7 on: May 01, 2012, 09:34:06 PM »


Quote
Are you sure? You might remember that I wrote you in a PM that when I used the standard recepy with 125 mg maltodextrine/250 ml water, my solution turned instant deep purple BEFORE I added the Na2CO3.
The last 2 colloidal gold batches I made, I used 1/2 tsp dextrin, and got perfect results.  Just now, I weighed that amount, and it was 1.3 grams.  When I post formulas, I post an exact amount that I know will work, and other people are able to reproduce it.  If I don't post exact amounts, people will want an exact amount anyway.

Later today, I will make another batch with maltodextrin instead of dextrin to see if it makes any difference.

As to the Czech report, that was about silver, and may not apply because of the difference in valence between silver and gold ions.  The lack of methods and procedural information in that report (it was actually a slide show presentation) makes it interesting but less than ideal.

Quote
Since maltodextrine is a mix of different carbohydrate chain lengths, could it be that a certain sugar/length is quicker to reduce?
Regardless of the chain length, it has only two ends, and only the ends having an aldehyde group can reduce a gold atom.  The difference in reducing ability is really the number of chain ends per unit weight, so naturally shorter chain lengths means more chains/chain ends capable of reducing something else, and therefore greater reducing ability.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #8 on: May 02, 2012, 01:03:01 AM »
Quote
Later today, I will make another batch with maltodextrin instead of dextrin to see if it makes any difference.

OK, I did the experiment with a 500ml 50ppm batch

I heated 500ml of distilled water containing 1 level teaspoon of maltodextrin to boiling in the microwave.
The boiling mixture was transferred to my hotplate/stirrer
I added 2.5ml of 1% gold chloride.  The solution stayed yellow after 15 seconds.
Next I added 40 drops of NaOH.  Each drop created red area in the liquid which mixed with the water.
The resultant colloidal gold is ruby red.  As perfect as it gets.

So, it worked fine with both CVS brand corn dextrin, and Carbo-Gain maltodextrin.

One thing to watch out for:  Gold should only ever be done in glassware, as any other metal except Platinum can and will reduce gold.  I have made colloidal silver ok in a metal container, but never gold.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

ShivaDestructor

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Re: Success factors - keep the intended water volume and the heat
« Reply #9 on: May 02, 2012, 08:25:20 AM »
One thing to watch out for:  Gold should only ever be done in glassware, as any other metal except Platinum can and will reduce gold.  I have made colloidal silver ok in a metal container, but never gold.

I've done three batches in SS pots. Since the SS surface is rather small compared to the volume (which I think about as an integral of a "reaction surface" where the thickness of that surface is at least an average of brownian motion, I hope you get my drift) and that the ionic gold is in the SS pot for a very short time until it has been transformed into nanorods/particles, I think that very little gold is lost to the pot.

Sure, when I check the bottom there was gold residue in the form of black specks and gold film in very few places, but the liquid when deep ruby red.

/J

Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #10 on: May 02, 2012, 01:11:37 PM »
Quote
Sure, when I check the bottom there was gold residue in the form of black specks and gold film in very few places, but the liquid when deep ruby red.
How much gold do you think you lost to the pot?  If you can see it, its not insignificant.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

ShivaDestructor

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Re: Success factors - keep the intended water volume and the heat
« Reply #11 on: May 02, 2012, 08:34:38 PM »
Quote
Sure, when I check the bottom there was gold residue in the form of black specks and gold film in very few places, but the liquid went deep ruby red.
How much gold do you think you lost to the pot?  If you can see it, its not insignificant.

There were about a dozen minute black specks, and on two-three patches 2-3 mm in diameter you could see a slight golden discoloration - approx area max 20 mm2.
Gold leaf for outdoor use weighs about 20 grams/1000 leaves. 1 leaf = 20 mg. Size 85x85 mm = 7225 mm2. Weight per mm2 approx 3 ug.
If you use gold leaf on something, you can' t miss it - it is gilded. The almost invisible discoloration in the SS pot was much less, almost an imperceptible golden tinge, see through.

For that particular batch I used 2 liters of DW and aimed for 40 PPM = 80 mg gold. That is 28900 mm2 when converted to gold leaf. If I had a FULLY gold leaf gilded spot of 20 mm2, I would have lost less than a 1/1000th of the gold.

I guess my loss on the spots was much less than that, but there was likely also reduced gold all over the pot but invisible. Gold leaf is approx 400 atoms thick, so when does it become invisible to the naked eye? Who knows... one thing is for sure - if 10% was lost the whole pot would have been quite golden. Electroplating (I guess this is one of your areas of expertise Kephra) is probably 10 atoms thick, and quite visible.

I think an insignificant amount of gold is lost if one is quick in making it in a metal container. I base this on the following:
1. Observation from my own experiments - same color and depth as colloidal gold made in glass container.
2. The above calculations/estimates.
3. The probability of getting more than 1% of the liquid/gold ions in contact with the SS surface in 30 seconds.

/J




Offline kephra

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Re: Success factors - keep the intended water volume and the heat
« Reply #12 on: May 02, 2012, 08:58:10 PM »
OK.  Thats a good analysis.

There is one other possible problem,  just possible, and that is whether the gold in contact with another metal forms seed crystals.  Some of the commercial gold nanoparticle manufacturers say that controlling the nanoparticle size requires having the right sized seeds.  I doubt this is a problem, but we are experimenting.

I used to gold plate quartz crystals by evaporating the gold in a tungsten filament, and gold is transparent when only an atom thick.  It actually looks green when you look through it.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

Offline lordkarma

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Re: Success factors - keep the intended water volume and the heat
« Reply #13 on: July 15, 2012, 09:42:38 PM »
Moved Question.
« Last Edit: July 15, 2012, 10:05:43 PM by lordkarma »

Offline mraluma415

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Re: Success factors - keep the intended water volume and the heat
« Reply #14 on: July 15, 2012, 10:02:58 PM »
could you teach me in some way, Kephra, to gold plate quartz? I am a jeweler and would love to give it a shot! ;D
"The art of healing comes from nature, not from the physician. Therefore the physician must start from nature, with an open mind." - Paracelsus