Try again.
> ----- Original Message ----- > From: M. G. Devour <[email protected]> > To: <[email protected]> > Sent: Monday, 27 September 1999 18:47 > Subject: Re: CS>Standardization - A Call for Standards! > > > > > [hanna's PWT] looks like the one. > > > > Ahh, good! Glad you think so. Saves you some money, too. > > > > > 0 - 99.9uS = 0 - 100 ppm as silver. > > > It turns out (as far as I can determine) that ppm as silver is > > > almost equal to the reading in uS/cm^2 in water. I don't know why I > > > haven't noticed this before!!! > > > > Ummm, what's the effect of particle size on this relationship? Since > > the conductivity is a function of charge carriers, if the silver is > > individual atoms, maybe it's correct, but what about fairly large > > particles? > > It seems to depend upon what the particles are composed. If the > particles contain a number of uncharged atoms along with charged atoms, > then the conductivity is the sum of the charges, but the concentration > of recoverable metal is the sum of both. (This is the most compelling > reason to limit the amount of cathode build up, as some inevitibly > enters the solution.) > However, if the particles are comprised wholey of charged atoms then the > conductivity reflects the recoverable metal. > > I will try and attach a gif of an early test result, which compares an > independent assay of total recoverable metal by Atomic Absorption > Spectrometry with my Ion Selective Electrode. There is only a couple of > ppm difference with the AAS result being higher. The sol was (and still > is, I keep samples) a light yellow, and was filtered at 0.2 um. > > The explanation above is the only I can think of. > > > I do remember when I had some stuff tested that I was off by only 20% > > or so... > > > > More to do! > > As always. > > > Mike D. > > Ivan. > >
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