Frank, down below, you say: "When viewing this plot, keep in mind that the TEM analysis indicated the particles were 1-2 nm in diameter."
Well, that is just NOT SO. The analysis did not say that; it said 90 % or so in the range of 1 to 8nm, with the predominant distribution in the 1 to 2nm and 6 to 8nm ranges. It's really quite difficult to argue clearly and logically with you when when written data is distorted by you so readily.... There were NO 125 nm particles in that sol, let alone the greater than 1 micron sizes your Zetasizer also supposes in the distribution analysis. Particles of that size easily show up in a laser beam. The TEM we have is spec'd to resolve to almost 2 angstroms. We don't pretend to get to those limits, nor do we pretend to be an absolute authority, but the size data we produce is consistent with other [Electron Microscopy] labs, not such far-out ranges as you purport. Further, none of the labs we have ever heard of use the equipment you describe -- or suggest its use -- for the purpose of characterizing to sub-nanometer particles. And since our data is consistent with other labs, my confidence in the TEM has nothing to do with personal belief either! Though, personally, and esp. after the observations noted above, I have little interest in carrying on what is clearly an impossible dialogue with a pedagogue. Nor do I wish to presume upon the patience of this list. Stephen -----Original Message----- From: Frank Key [mailto:[email protected]] Sent: Wednesday, March 21, 2001 8:16 PM To: [email protected] Subject: Re: CS>Colloid Surface Area Stephen wrote: > I'm sorry, Frank, we did not see ANY particles in the range [you say] of > 125nm in Ole Bob's sample. NONE. That is my point precisely. What a PCS sees, you do not see. I have pointed this out before, due to the large amount of silver oxide formed when the water is evaporated, the real particles are swamped out. For those who are interested to see the size distribution plot of Bob's sample, it can be viewed on my web site. This is a two page report, on page two are details of particle size by volume. See the plot at: http://www.silver-colloids.com/Reports/testplot.html This plot was made by a Photon Correlation Spectrometer (PCS) instrument designed specifically to do nanometer particle size characterization studies. The instrument is built by Malvern Instruments Ltd of the UK, one of worlds leading producers of such instruments. When viewing this plot, keep in mind that the TEM analysis indicated the particles were 1-2 nm in diameter. Stephen, feel free to believe what ever you chose. You have a vested interest in believing that your instrument provides useful images. It is in your best interest to hear nothing that conflicts with that viewpoint. Enough said. frank key -- 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] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
