Chlorine Analysis by Coulometry
R-X + O2 --> HX + CO2 + H2O
The combustion gas, carrying halide ions, is led into a sulfuric acid scrubber for effective water and interference removal. The dried and clean gas is led into the temperature controlled titration cell, where the halide ions react with silver ions, present in the titration cell. The amount of charge (the integral of the regeneration current over the measuring time) used to regenerate the lost silver ions, is directly related to the Total Chlorine (TX) content of the sample.
The equations for this reaction are:
HX + Ag+ --> H+ + AgX
Ag --> Ag+ + e