Accurate detection of trace ammonia in water vapor system of power plants plays an important role in optimization operation of water treatment system and condensate water polishing system.The ammonia electrode method

ammonium ion selective electrode method and Nessler's reagent spectrophotometry method were adopted to determine the ammonia concentration in water vapor system

and the results were compared.The accuracy and precision of the electrode methods were investigated.Moreover

effect of hydrazine on determination results by ammonia electrode method was also observed.The results showed that

when the ammonia concentration in standard water sample was within the range of 0.0mg/L to 3.0mg/L

the relative standard deviations(RSD)of two electrode methods were both lower than 0.5%

and the RSDs of above three methods for ammonia content detection in actual water from power plants were all within ±0.05mg/L.This indicated that the two electrode methods had higher accuracy and precision

hydrazine in water samples had no influence on the ammonia electrode determination

and the ammonia electrode method had the advantages of simple operation

less interference factors and high accuracy

it can be applied to daily water vapor quality supervisory control in power plants.