Re: Followup to PPM techniques
Excellent point. Apparently there are electrostatic issues to be dealt with in filtering that finely. The tech that I spoke with at Osmonics said that they have a "device" that they sell for the explicit purpose of electrically neutralizing the filters before use. Bill Kingsbury wrote: > > I agree with Bruce's cautions. Filtering would require accurate > testing, before it's effects could be accepted, or rejected. > First we need to establish the 'accurate testing'. > > Ignoring the cost issue, could 'centrifuging' be technically > useful in some cases ? > > --Bill > > 7-30-98, Bruce wrote: > > > >A thought on filtering these charged silver particles; will charged > >ions of silver tend to be attracted to the filter matrix, even when > >small enough to pass otherwise, because of their charge? > > > > -- > 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: > silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com > with the word subscribe or unsubscribe in the subject: line. > > To post, address your message to: silver-list@eskimo.com > > List maintainer: Mike Devour -- 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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the subject: line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour
Re: Followup to PPM techniques
I agree with Bruce's cautions. Filtering would require accurate testing, before it's effects could be accepted, or rejected. First we need to establish the 'accurate testing'. Ignoring the cost issue, could 'centrifuging' be technically useful in some cases ? --Bill 7-30-98, Bruce wrote: > >A thought on filtering these charged silver particles; will charged >ions of silver tend to be attracted to the filter matrix, even when >small enough to pass otherwise, because of their charge? > -- 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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the subject: line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour
Re: Followup to PPM techniques
Bruce wrote: > A thought on filtering these charged silver particles; will charged > ions of silver tend to be attracted to the filter matrix, even when > small enough to pass otherwise, because of their charge? > > A suggested experiment: > > Take your average batch of CS just after production, test it with a > TDS1 or similar, then run it through the filter you're now using > (coffee filters for most of us) and then retest with the TDS1... > > Is there a drop in the reading? If so, is this drop really > reflecting a filtering out of coarse particles, or is it caused by > charged particles being attracted to the filter media, and being > held there? Try filtering the same batch again in a new filter? See if the ppm reading drops again by a similar or somewhat smaller amount. Other than filter inefficiency, there shouldn't be much to remove on the second pass. Also, try two different volumes to test, different by a factor of two. If it's an effect of the filter surface area adsorbing particles the smaller sample will see a larger drop in ppm than the bigger sample, since the rest of the CS in the bigger sample will go through essentially unfiltered after the surface saturates. (If that's not clear, don't worry. It's pretty murky to me too!) I think these *might* be valid tests. Just guessing at this point. Be well, Mike D. [Mike Devour, Citizen, Patriot, Libertarian] [mdev...@mail.id.net ] [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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the subject: line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour
Re: Followup to PPM techniques
Mike, A thought on filtering these charged silver particles; will charged ions of silver tend to be attracted to the filter matrix, even when small enough to pass otherwise, because of their charge? A suggested experiment: Take your average batch of CS just after production, test it with a TDS1 or similar, then run it through the filter you're now using (coffee filters for most of us) and then retest with the TDS1... Is there a drop in the reading? If so, is this drop really reflecting a filtering out of coarse particles, or is it caused by charged particles being attracted to the filter media, and being held there? Bruce Stenulson M. G. Devour wrote: > > Doug McMurtrie wrote: > > > ... the TDS-1 would, I think, take care of the ppm part. > > Or it will, when we go ahead and do some cross-testing with the other > lab methods. > > > I have been wondering lately if there are any mechanical filters > > capable of operation at such small sizes. ... If a mechanical > > filter were available with an absolute filtering ability of say .02 > > microns ... With a batch that was filtered and then ppm tested we > > could have a pretty good idea of just what we had without expensive > > and time consuming lab tests. > > I just checked in my trusty Fisher Scientific catalog, and there are > lots of different filters in the range of 0.2 microns and above, and > many down to 0.1 microns. I did find one interesting entry, Alumina > matrix filter membranes from Whatman, in 0.2 micron, 0.1 micron, and > 0.02 micron!! Not cheap, but would give you a decent idea of what > concentration of bioactive particles you have. > > So careful filtration/separation techniques could be used. > > Be well, > > Mike D. > [Mike Devour, Citizen, Patriot, Libertarian] > [mdev...@mail.id.net ] > [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: > silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com > with the word subscribe or unsubscribe in the subject: line. > > To post, address your message to: silver-list@eskimo.com > > List maintainer: Mike Devour -- 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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the subject: line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour
Re: Followup to PPM techniques
Doug McMurtrie wrote: > ... the TDS-1 would, I think, take care of the ppm part. Or it will, when we go ahead and do some cross-testing with the other lab methods. > I have been wondering lately if there are any mechanical filters > capable of operation at such small sizes. ... If a mechanical > filter were available with an absolute filtering ability of say .02 > microns ... With a batch that was filtered and then ppm tested we > could have a pretty good idea of just what we had without expensive > and time consuming lab tests. I just checked in my trusty Fisher Scientific catalog, and there are lots of different filters in the range of 0.2 microns and above, and many down to 0.1 microns. I did find one interesting entry, Alumina matrix filter membranes from Whatman, in 0.2 micron, 0.1 micron, and 0.02 micron!! Not cheap, but would give you a decent idea of what concentration of bioactive particles you have. So careful filtration/separation techniques could be used. Be well, Mike D. [Mike Devour, Citizen, Patriot, Libertarian] [mdev...@mail.id.net ] [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: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the subject: line. To post, address your message to: silver-list@eskimo.com List maintainer: Mike Devour
