Thanks again. I keep fantasizing that I can buy a laser pointer, rig it up to a protractor with a micrometer to tilt the thing, and use a simple photo detector to measure light output at varying angles to the incident beam and plot particle size.
If there is a minimum particle size, we have no need to know the population range; only the upper limit and lower limit. We can test for silver in solution chemically; I think.,so the problem becomes screening for the largest size based on intensity at various angles. . Knowing very little these things, I have even looked into simple filtration, but the pore size seems too variable. Thanks much for the info; don't hesitate to let me know when you are to busy to respond. James Osbourne, Holmes [email protected] -----Original Message----- From: Ivan Anderson [SMTP:[email protected]] Sent: Monday, December 21, 1998 12:03 AM To: [email protected] Subject: Re: CS>Particle sizing James, I think you are right, size range must present problems, and I guess one can only expect to get a report on the range ie bigger than this and smaller than that with most being this. But it seems that sizing particles under 1nm is a problem on its own. Light Scattering Electrophoresis (LSE) would seem to be fairly simple and cheap? particles are caused to move across a field viewed by a microscope, by having a potential applied across the cell containing the colloid. A laser focused on the colloid causes scattered light to show as twinkly stars in the viewpiece and one measures the time it takes these to cross a predefined distance. Applying some math and viola, mass of particle. There are machines that do all this automatically of course and they generally can supply the Zeta Potential which is a function of stability. All this stuff is out of my price range for now, but at least when I am ready to find a lab that can do particle sizing I will know more or less whether what they recommend is what I want. Ivan -- 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]> -- 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]>
