This standard applies to all types of water in boiler operation, with a hydrazine content of at least 10 ng/l. Uzer(ll) and copper(l) do not interfere with the determination if less than 0.25 mg is present in the analysis sample. Ammonia and hydroxylamine do not cause any problems, even in large excess.
NEN 6548-1988 history
1988NEN 6548-1988 Water in boiler plants Photometric determination of hydrazine content