As a former chemist who switched careers to computer engineering --- unless there have been recent breakthroughs of which I am not aware, the most specific and reliable test for presence of a specific element in small concentrations is atomic absorption. This requires an expensive instrument and a separate lamp for each element (such as Silver) for which you want to test, so it would probably require a commercial venture or large research operation to justify the cost. It may not be able to distinguish between suspended neutral silver, colloid, or dissolved ionic silver, but will definitely give reliable information on ppm Ag.
-----Original Message----- From: M. G. Devour <[email protected]> To: [email protected] <[email protected]> Date: Thursday, November 11, 1999 6:15 AM Subject: Re: CS>wet chem > Shouldn't there be a way to perform some regular wet chemistry test > to determine PPM? Something like a simple titration or something? > joe... Joe, I've been asking that question on and off for 2 1/2 years, and I've never gotten a good answer. The analogy of titration was always the first thing to come to mind. Shoot, I'd expect you could create a kit of dyes and reagents similar to that used to test a swimming pool and be able to get crude readings by color. Even that much would be helpful. Even if you had a fairly complex setup using a number of reagents and a bunch of glassware, it would still be cheaper than some of the instruments folks have had to buy. I'd like to see us do a survey of analysis techniques and maybe create a table of equipment cost, cost per sample, accuracy and precision, complexity, safety, etc. At least over narrow ranges of process conditions there *is* a correlation between conductivity and concentration. But to peg that measurement to anything *known* still requires other methods for calibration. It's a great question. I hope we're closer to finding an answer. Be well, Mike D. [Mike Devour, Citizen, Patriot, Libertarian] [[email protected] ] [Speaking only for myself... ] -- 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]>
