Avtor/Urednik		Khan, SA; Mulvaney, RL; Strle, K; Horgan, BP
Naslov		Evaluation of diffusion for inorganic-nitrogen analysis of natural water and wastewater
Tip		članek
Vir		J Environ Qual
Vol. in št.		Letnik 29, št. 6
Leto izdaje		2000
Obseg		str. 1890-5
Jezik		eng
Abstrakt		Public concern that agricultural use of N fertilizers may have adverse effects on environmental quality and human health has led to a growing need for reliable data concerning the concentration of inorganic N in ground and surface water. A study was conducted to compare the accuracy and precision of simple Mason-jar diffusion methods for quantitative determination of NH+4 and NO‐3, in a wide variety of water and wastewater, relative to colorimetry, ion-selective potentiometry, and steam distillation. Good agreement among methods was generally obtained with standard solutions prepared using deionized water; however, substantial differences often were observed with natural and anthropogenic samples, because of either Cl‐ interference in measurements with the NO‐3 electrode or CO2‐3 interference in distillation. Analytical accuracy also was evaluated by measuring recovery of N added as (NH4)2SO4 or KNO3, (6 mg N L‐1). With most of the samples studied, quantitative recovery (97‐103%) was not achieved by potentiometry or distillation. Quantitative recoveries usually were achieved by a manual Berthelot method for colorimetric determination of NH+4, whereas recovery was often incomplete when NO‐3 analyses were performed with an automated flow-injection system using Cd2+ reduction. Regardless of the sample matrix, diffusion was always accurate in measuring recovery of NH+4 or NO‐3.
Deskriptorji		FRESH WATER WATER POLLUTANTS, CHEMICAL SEWAGE AGROCHEMICALS NITROGEN NITRATES AMMONIA CALORIMETRY POTENTIOMETRY