Abstract An improved flow independent method for electrochemical monitoring of a sample stream for the total concentration of a series of ionic species of the form X -n , H m X -n+m where n varies from 1 to m and X -n is an anion selected from the group consisting of fluoride ion, F - , and sulfide ion S -2 . The pH of the sample stream is adjusted to a value below the pk a of the neutral most protonated species of the series. A first electrode sensitive to the activity of X -n is placed in the adjusted stream. The electric potential developed thereby is measured. A second electrode sensitive to the activity of hydrogen ion H + is also placed in the adjusted stream. The electric potential developed thereby is also measured. The potential difference between the first and second electrode is a measure of the total concentration of the series X -n , H m X -n+m .
An improved pH independent method for monitoring of a sample stream for the total concentration of a series of ionic species of the form X -n , H m X -n+m , where m varies from 1 to n and X -n is an anion selected from the group consisting of fluoride ion F - , and sulfide ion S -2 , said method comprising the steps of: adjusting or maintaining the pH of the sample stream to a value below the pk a of the neutral most protonated species of the series; placing only a first electrode and a second electrode in the adjusted stream such that the electrodes are in direct contact with the adjusted stream, said first electrode being sensitive to the activity of X -n and said second electrode being sensitive to the activity of hydrogen ion H + ; and measuring the potential difference developed between the first and second electrode, said difference indicating the total concentration of the series in the stream.
Claim 2
Dependent Claim
168 words
An improved pH independent method for monitoring of a sample stream for the total concentration of a series of ionic species of the form X -n , H m X -n+m , where m varies from 1 to n and X -n is an anion selected from the group consisting of fluoride ion F - , and sulfide ion S -2 , said method comprising the steps of: adjusting or maintaining the pH of the sample stream to a value below the pk a of the neutral most protonated species of the series; placing only a first electrode and a second electrode in the adjusted stream such that the electrodes are in direct contact with the adjusted stream, said first electrode being sensitive to the activity of X -n and said second electrode being sensitive to the activity of hydrogen ion H + ; and measuring the potential difference developed between the first and second electrode, said difference indicating the total concentration of the series in the stream.
Claim 3
Dependent Claim
19 words
Method of claim 1 where the series contains the species S -2 ion, HS - and H 2 S.
Claim 4
Dependent Claim
14 words
Method of claim 2 where the pH is adjusted to a value below 5.
Claim 5
Dependent Claim
15 words
Method of claim 1 where the series contains the species F - ion and HF.
Claim 6
Dependent Claim
14 words
Method of claim 4 where the pH is adjusted to a value below 2.5.