Technical note: interference of Br-, BrO3-, and ClO3- with DOX determination.

In the dissolved organic halogen (DOX) analytic test, prior to combustion, the granular activated carbon (GAC) on which the DOX is absorbed is washed with a sodium nitrate solution designed to remove any inorganic chloride that may have also adsorbed to the GAC. Thus, a potential positive interference is removed. This study investigated the effectiveness of the nitrate wash in eliminating possible interferences from bromide, bromate, and chlorate ions. No interference was detected from bromate or chlorate ion, but a small positive interference of about 12 micrograms Cl-/L per mg/L of bromide ion was found in the presence of background organic matter.