Measuring oxidant species in ELECTROLYZED salt brine solutions

The electrolysis of salt brine solutions by onsite generators produces chlorine (free available chlorine [FAC = Cl2, HOCl, and OCl–]) at concentrations ranging from 200 to 1,000 mg/L. There is some speculation that the electrolysis of salt brine also produces chlorine dioxide (ClO2) and ozone (O3). The analytical methods frequently cited for measuring ClO2 and O3 in anolyte liquors following salt brine electrolysis are the DPD and indigotrisulfonate methods. These analytical procedures are routinely used to measure drinking water residuals in finished water. However, when used for measuring components in electrolysis cell liquors, false‐positive results are observed.