848 AMMONIUM - DISTILLATION METHOD
By Special Request
Quantitation of Ammonium using the distillation method.
Summary: This method involves the quantitation of ammonium (NH4-N) in water and waste water. Samples are pH adjusted to pH >9.5, steam distilled into dilute sulfuric acid and analyzed by flow injection analysis (FIA). Ammonium concentration is determined by FIA using the color reaction of NH4 with salicylate, nitroprusside and hypochlorite in an alkaline phosphate buffer. The absorbance of the reaction product is measured at 660 nm. The method has a detection limit of approximately 0.5 mg/L and is generally reproducible within 8%.
The Lab requests a sample size of at least 250 mL. Samples should be frozen or refrigerated until delivered to the lab. Acidification with sulfuric acid to pH < 2 can be used as a preservative.
U.S EPA, 1999. Method 1690, Ammonia-N in Water and Biosolids by Automated Colorimetry with Preliminary Distillation.
Switala, K. 1999. Determination of Ammonia by Flow Injection analysis. QuikChem Method 10-107-06-1-A. Lachat Instruments, Milwaukee, WI.