Determination of the total dissolved sulphide in the pH range 3-11.4 with sulphide selective ISE and Ag/A92S electrodes.
An electrochemical method for the determination of the total sulphide concentration of sewage water samples has been studied using a potentiometric cell containing either a sulphide ion selective ISE-glass electrode pair or a Ag/Ag(2)S electrode-glass electrode system. The performance of the two sulphide ion sensors was investigated and compared in both acidic and basic pH ranges. It was proved that the cell potential can be made directly proportional to the logarithm of the total sulphide concentration when both the pH < lg K(2) - 1.5 condition (acidic range) and also when the lg K(2) + 1.5 < pH < lg K(1) - 1.5 condition prevails in the system (alkaline range); where K(1) and K(2) are the first and second protonation constants of the sulphide ion, respectively. A suitable calibration method for a wide range of sulphide concentration is also presented for both ranges of the pH scale. The overall performance of the measuring system was tested using model solutions and real waste water samples.
Schmidt
E
E
Department of Analytical Chemistry, University of Veszprém, Veszprém, Hungary.
Marton
A
A
Hlavay
J
J