----- Original Message ----- From: Hutt William J (Bill) DLPC <hut...@ncsc.navy.mil>
> I've read many e-mails on this forum about achieved ppm, but little on > how the parties accomplished and confirmed their results. It would be nice > to create a data base of methods in order to create a standard. This is supposedly under way, at least I have made an initial contribution, with more to follow as I find the time. > I have seen a couple of e-mails which addressed using a volt-ohm-meter > to read ppm. > Example: 4usec/cm = 1/250kohms; this measurement appears to be achieved > by placing the VOM probes in the CS solution at a spacing of 1cm. > > Example2: 1ppm = 1.6usec/cm (+/- 20%); If both examples are correct then > 5ppm would be equal to 5ppm X 1.6usec/cm = 8usec/cm > 8usec/cm = 1/R = 125kohms resistance between the VOM probes which are > spaced 1cm apart in the CS solution. If only it were that simple... Specific conductance is defined as consisting of a cell (portion of solution) 1 cubic centimetre in dimension bounded on two opposing sides by electrodes 1 cm square. So you can see that simply placing VOM probes into the solution will not correlate (unless you know the cell constant that these probes would develop). Also, conductivity measurement is generally performed using an AC potential field of some 10K Hz or so to avoid elctrolytic action and electrode polarisation. In other words, one is better off using a cheap conductivity meter. Concerning the examples you quote: 1. 4uS = 1/250K ohms by definition. 1S = 1/1ohm 2. The equivalent weight of silver is 1.08 therefore the ppm as silver ions (unless I am mistaken) is the conductivity measurement x 1.08, not 1.6 as someone reported. I questioned that figure when it was posted but did not recieve a reply (may call into question the accuracy of some commercial CS machines that have been sold). > If we can gather data from known ppm solutions using the above method ,a > rough standard could be established and everyone would know about what > strength of CS solution they have produced. > > Resistance measurements of 5ppm, 10ppm, 20ppm, and 30ppm should give a > well rounded data base. As explained, unless everybody uses the same conductivity (resistance) parameters the results will not transfer from generator to generator. Also there is a question about how reliable these results will be with regard to the particle size of the colloid, although I have had good correlation in my results between conductivity readings and ppm in my clear and light yellow sols, more work needs to be done with darker coloured CS products. For what it is worth the specific resistance for the concentrations you mention are: 5ppm - 215K ohms 10ppm -107.5K ohms 20ppm - 53.7K ohms 30ppm - 35.8K ohms > I realize that their are many other factors to consider when trying to > measure ppm. The purpose of this e-mail is to try and establish a standard > by which everyone can use without purchasing some expensive high tech > device. > > If a simple standard has already been established, what is it? > > I would like to know if anyone has a recipe for making colloidal silver > salve. > > Thank you, > > BillH Regards - 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: 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 <mdev...@id.net>
