Ivan Anderson wrote: > Marshall wrote in reply to a post by me: > > Marshall, thanks for the advice, but I have already spent long hours > at the university science library studying colloid chemistry and > modern colloid chemistry. > The fact that particle size influences colour is not disputed by me, > as previous posts will testify. What I am disputing is that a silver > colloid at a concentration above 5 ppm does not have more particles, > but the same number of particles of a larger size, a point you did not > address in your reply. >
I have no references that I can cite. Only experience. That is why I would like to acquire some colloid at higher ppm that is clear and run tests on it to see where the disagreement is coming from. Either ppm is lower than thought, something is different to allow this to happen from what we have tested, or the subjective viewing of the colloid to determine what is "clear" and what is "colored" is different. I do know that what I call gold, appears totally clear when put into an 8 oz glass, but it will appear gold when in a gallon glass jug. > The fact remains, that I and others produce water clear silver sols > at much higher concentrations than you would allow, which means more > particles of a similar size surely. > Yes that would be indicated. > The difference between a 5 ppm sol (0.0005% by weight) and a 20 ppm > sol (0.002%) is actually quite small and I suspect it is the > generating parameters not the concentration that determines the > particle size. > Generating parameters, as well as temperature, exposure to UV light and so forth are very important. What I have been doing is optimizing all parameters for minimum size, and testing. > There are reasons for this which I don't fully understand, but which > involve zeta potential, silver 'crystal' configuration, electrode > current density, etc. > Higher zeta potential should allow one to go to higher ppm with the same particle size. I wish I had a way to measure zeta potential, but all the instruments I have looked at are way our of my price range. Do you have a method of measuring zeta? > The Ion Selective Electrode method is probably the only way to measure > the the ionic concentration of a colloid. The silver ISE is specific > to silver and will measure nothing else. It will measure > concentrations from 0.01 - 107,900 ppm directly. All other methods, > except for chemical (as far as I know) measure total silver content, > that is elemental silver and ionic silver. My results have excellent > correlation to those of the accredited lab I have contracted to > independently test my product, using the Atomic Absorption (AA) > method. I am intrigued by this device. Do you know where on the web I can find more information on it? We may want to acquire one to improve our testing ability. I have done some searching on the net for "silver ISE", but have not found any references. Maybe you can explain more how it works. I had assumed that something that measures the ionic concentration would give a low ppm measurement for a colloid. Would this not be true? It seems that it would either measure each multi-atomic particle as one atom, or as how many atoms were represented by the charge on the particle. Both of these should give a ppm that is less than actual. If it is giving actual ppm, accurately, on colloids, then I don't understand the mechanism by which it works. Thanks, Marshall -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
