[Study on determination of ammonia-nitrogen in water by ammonia gas sensor electrode]

A method for the determination of NH3-N content in water by ammonia gas sensor electrode was studied systematically. Good results were obtained by adding acid to water samples until pH less than 2 for storage and adding EDTA to prevent metal ions from interference. Recoveries varied in the range of 90-104%, and the coefficients of variation less than or equal to 3.4%. The measurement range was 10(-1)-10(-4)micrograms/ml, and the detection limit 0.13 micrograms/ml. The reliability of the method was confirmed by comparison with Nesslerization (P greater than 0.5). This method is simple, rapid, accurate and can directly be applied to the determination of the content of ammonia-nitrogen in colored and turbid water samples.