Research Product

The widely used procedure of measuring the iodine produced by reacting millimolar KI at pH4 with 'residual oxidants' was found to underestimate the total oxidants in chlorinated seawater by up to fifty percent. Approximately four hours is required for complete reaction of the KI with the oxidants and rapid titrations are in serious error. The total oxidants can be measured by making the samples pH2 and KI 20 millimolar. The slow reacting species could be some form of bromine. Ultraviolet spectra do not show any chlorine species in chlorinated seawater, but rather show the hypobromite peak. The spectra give no indication of bromine chloride complexes at pH8. Polarographic measurements do not show significant concentrations of bromate, unless the samples are exposed to sunlight. Oxyanions or chloride complexes of bromine do not appear to be the slow reacting 'residual oxidant'.