Author Topic: Light and turbidity  (Read 2531 times)

SanchoPanza

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Light and turbidity
« on: July 02, 2015, 11:56:52 AM »
With about 6 batches under my belt now, I've noticed something I haven't seen mentioned here.
While checking my colloidal silver with light for turbidity, I've notice that some turbidity, which does not show up with a red laser is clearly visible with a  focused flashlight. So I also tried different colored leds and also got variable results.

The best example of this is with my latest Karo batch.
There is almost no visible turbidity with 660nm red laser light, but the same sample shows a strong Blue beam with  focused white light.
My agave samples started out with the same effect, but after sitting a few days, I can see turbidity with both lights now.
With cinnamon, turbidity turned gray, yet the solution is still yellow. It showed turbidty with every colored light, Red, yellow, orange, green and blue. (the green and blue lights were not bright, or focused enough to rely on the results).

Also, some reducers caused the turbidity to be different colors. My agave went from a blue turbidity beam, to gray in about 5 days.
The colloidal silver itself is still the same shade of yellow. Same with cinnamon, turbidity turned gray, yet the solution is still yellow.
Of course it's always red with the laser light, so white light seems to do a better job of revealing what's going on as colors shift, based on the light source.

Karo is my clearest so far, and the turbidity and color has not changed in 3 days.
Karo shows the biggest difference in what type of light is used, as the laser is almost invisible, and white light creates the most "Blue" turbidity of all the formula's I've tried so far.

Not sure what wavelength of light to use for this test.

-Sancho

Offline kephra

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Re: Light and turbidity
« Reply #1 on: July 02, 2015, 12:08:50 PM »
If the particle size is a substance which does not produce the surface plasmon resonance, then the shortest wavelength of light will show the smallest particles (non silver nanoparticle, like silver oxide or super large silver metal crystal).
Particles which show up in blue light but not red are smaller than particles which show up with red light.

IE: you can see smaller things with blue light than red.

There are three things that cause turbidity. 
A) Silver oxide particles which have precipitated.
B) Silver metal dust which was swept from the cathode
C) Foreign material from the reagents.

If the silver is reduced and there is silver oxide precipitates left, then that will probably clear eventually as the silver oxide slowly dissolves.  The solution will then become darker over time as the silver oxide is reduced and makes either more nanoparticles, or larger nanoparticles.

If the turbidity is caused by silver dust from the cathode, it might settle out over time depending on the size of the dust particles.
Colloidal Silver is only a bargain if you make it yourself.

SanchoPanza

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Re: Light and turbidity
« Reply #2 on: July 02, 2015, 12:30:15 PM »
I undersatnd the red/blue/size part, thanks for the explanation.
Does a stronger blue turbidity beam, (with white light), in the karo makes sense then?
What cause the older samples, (cinn and agave), to turn from blue to gray?

I assume they're not as "stable" as they should be.

-Sancho

Offline kephra

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Re: Light and turbidity
« Reply #3 on: July 02, 2015, 12:40:20 PM »
Gray particles are super huge meaning the particles have grown in size.  The next step is for the solution to become clear as the extra large particles fall out.
Colloidal Silver is only a bargain if you make it yourself.

SanchoPanza

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Re: Light and turbidity
« Reply #4 on: July 02, 2015, 01:00:48 PM »
I'll watch for it to go clear.
I guess that explains the blue beam turning to gray over time, because the particles are still growing.
Thank You,

-Sancho

Offline RickinWI

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Re: Light and turbidity
« Reply #5 on: July 02, 2015, 06:08:52 PM »
Well this is interesting. I have been fighting turbidity for almost 3 years and had never noticed many of these things such as color of the turbidity in the beam, etc.

Of course I look closely at the color of the colloidal silver in different lighting conditions but when it comes to the turbidity the only thing I have ever looked for is the total amount of "fog in the headlights".  I have a few strong focused beam flashlights but I think they are all aprox the same color of white.

Expanding on what Kephra mentioned about the 3 causes of turbidity, here are possible causes for each one of those:

A) Silver oxide particles which have precipitated.
  1. Too high of a current for the anode size and amount of stirring.
  2. Voltage across electrodes too low.
  3. Not enough electrolyte so pH too low for the type of reducer you are using to work properly.
  4. Doing the electrolysis at too low of a temp (like under 70* F)
  5. Running electrolysis for too long so your IS gets above 20 PPM at room temp.
  6.

B) Silver metal dust which was swept from the cathode
  1. Not enough electrolyte to prevent silver from gathering at the cathode.
  2.

C) Foreign material from the reagents.
  1. Unclean glassware, anode or cathode.
  2. Contamination in DW or in Electrolyte solution.
  3. "Other stuff" that might be in something like Cinnamon Extract, etc.
  4.

D) Less than optimal procedure for the type of reducer you are using.
    (I have found that each different reducer has it's own favorite pH and temp for the reduction to produce it's best possible color & clarity. Please note: YMMV)
  1. Cinnamon Extract: if you do the reduction at room temp = slightly more turbid.
  2. Cinn Ext: if you get the IS up to boiling on hot plate and then add the Cinn Ext it will be dark & turbid. (optimal I have found for Cinn Ext = get IS to about 180*F then add Cinn ext one drop at a time on stirrer.)
  3. Karo, Dextrose or Fructose: if you get the IS up at high temp and then add the reducer it will be slightly more turbid. (optimal I have found is to reduce right after electrolysis with no added heat so in the upper 70*'s.)
  4.

I took the liberty of adding a fourth category (D). As I mentioned YMMV and some things in that category may be closer to opinions rather than facts? Many things are dependent on numerous variables.

Hopefully Kephra could fill in the blanks with things I haven't thought of and correct any incorrect statements.

@ Sancho: I take it then that your Agave bottle is in the pantry & your Karo bottle is sitting next to your stirrer  ;)
So many VARIABLES & so little TIME.

SanchoPanza

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Re: Light and turbidity
« Reply #6 on: July 02, 2015, 11:40:01 PM »
Thanks guys. I have a lot to digest, just from what you've given me so far.
Clarity is my project for now, so I'm likely just being extra observant and critical.
I expected in my gut, to see different things with different wavelengths, but I thought the results would be more intuitive to interpret.
Except for a 2" electrode spacing, the rest of my process has been to Forum "spec", and all is working well.
I will stay with karo for now, (Yes Rick ;) ), and explore with voltages and currents, and also decide on the coin or the wire anode.
I will try to get a few good pics of the different turbidity colors, or characteristics.
It's a subtle effect, until you notice it.

-Sancho

Offline RickinWI

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Re: Light and turbidity
« Reply #7 on: July 03, 2015, 12:23:16 AM »
 @ Sabncho, Since you like experimenting, I would say that you are ready to move on to Maltose if you want to try that. I really haven't made all that many Maltose batches (dozen?) so maybe you will find a way to fine tune it even more (less Electrolyte?, a little more?, warm when reduce?, hot when reduce? etc.)  Your Karo Reduced is probably just about as good as it's gonna get as far as clarity or lack of turbidity.

If your "coin" is .999 bullion then why not give that a try. Spreads out the production of silver at the anode so things are not so crowded. That allows you to use higher current if you wish but you don't have to. Also for the same size batch of 20 PPM it will spread out the black oxide so that is not affecting the resistance. They say bigger is better  ;)
So many VARIABLES & so little TIME.

SanchoPanza

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Re: Light and turbidity
« Reply #8 on: July 03, 2015, 12:53:59 AM »
I do like experimenting.
Are you sure I'm ready for the MDR? I just barely met the mandated 5 karo batches.  ;)

Yes, the coin does spread the oxide out more, and it does seem to prefer a higher voltage, and in the two batches I compared, turbidity was lower with the coin @ 16v, than the wire @ 10v. However, I would need to see that repeated two more times before I say it out loud.
But if you wanna start comparing Maltose notes,  that would be great.

BTW, what should the room temp, shelf life be, for 20ppm, warm IS, Karo reduced?

My cinn lasted 3 days before my blue beam turned gray.
2 days for agave.
The karo still looks great after 3 days, Plus vinegar overnight. (1:50)
All batches are still yellow, including my very first, with agave.

Note; Although the Karo is still yellow and clear, the blue beam (white light) is just starting to turn gray.

-Sancho



Offline kephra

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Re: Light and turbidity
« Reply #9 on: July 03, 2015, 01:05:30 AM »
Shelf life with karo reduced is years.
Colloidal Silver is only a bargain if you make it yourself.

SanchoPanza

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Re: Light and turbidity
« Reply #10 on: July 03, 2015, 01:33:07 AM »
Shelf life with karo reduced is years.

This is going to take a bit longer than I thought... :o

-Sancho