Ammonia Test Kits

Direct Nesslerisation Method

The CHEMetrics Ammonia test kits employing the well-established Nessler reagent* to determine ammonia concentrations are applicable to drinking water, clean surface water, good-quality nitrified wastewater effluent, and seawater testing. The supplied stabiliser solution is used with some waters where the calcium and magnesium concentrations causes cloudiness of the reagent. Adding a few drops of the stabiliser solution (Rochelle Salt) will prevent this cloudiness. References recommend distilling samples prior to analysis. Results are expressed as ppm (mg/l) ammonia-nitrogen, NH₃-N.

Although the Nessler reagent is itself stable, its high alkalinity attacks the glass ampoule over time, resulting in a precipitate which interferes with colour comparison. We recommend refrigerating these ampoules when not in use, which will dramatically extend their shelf life by 18 months. If stored at room temperature, CHEMets® and HR CHEMets® ampoules have a shelf life of 6 months and Vacu-vials® ampoules have a shelf life of 3 months from date of manufacture. We suggest stocking kits and refills accordingly. The K-1513 Vacu-vials kit employing the Direct Nesslerisation (Extended Shelf Life) chemistry is stable without refrigeration for 16 months from date of manufacture.

References:
ASTM D 1426-08, Ammonia Nitrogen in Water, Test Method A.
APHA Standard Methods, 18^th ed., Method 4500-NH₃ C - 1988.

Technical Data Sheet

Hydroxybenzyl Alcohol (HBA) Method

In the ammonia test method that employs the Hydroxybenzyl Alcohol chemistry, free ammonia reacts with hypochlorite to form monochloramine. Monochloramine reacts with HBA, in the presence of sodium nitroferricyanide, to form a green coloured complex. This test method measures the sum of free ammonia and monochloramine. Results are expressed in ppm (mg/l) ammonia-nitrogen, NH_3-N.

The Hydroxybenzyl Alcohol Method offers sensitivity similar to the Nesslerisation Method but with the added benefit of being Mercury-free, thus not generating any Mercury-containing waste.

Reference:
Krom, Michael D., Spectrophotometric Determination of Ammonia: A Study of a Modified Berthelot Reduction Using Salicylate and Dichloroisocyanurate, The Analyst, v.105, pp. 305-316, 1980.

Technical Data Sheet

Technical Bulletin: Free Ammonia Analysis (HBA) in the Presence of Monochloramine

Applications

Higher ammonia concentrations in surface waters can indicate contamination from waste treatment facilities, raw sewage, industrial effluents (particularly oil refineries), or fertiliser runoff. Regulatory requirements mandate ammonia monitoring for diverse industries to protect downstream aquatic environments, such as wastewater, landfill, acid mine drainage and animal feeding operations, where ammonia is measured in effluent, leachate, and unintended discharges. Environmental scientists often test water bodies for ammonia to help them assess trends associated with other aquatic health indicators. The aquaculture industry frequently measures and controls ammonia concentration to keep fish and shellfish alive and healthy. The Specified Concentration or Value (SCV) for ammonia in drinking water supplies in the UK is 0.50 mg/l (ppm), and in Ireland is 0.3 mg/l (ppm).

What is Ammonia?

Ammonia is an inorganic form of nitrogen that contains hydrogen. It is a plant nutrient often found naturally in water at low levels due to the decomposition of organic plant or animal matter. Higher concentrations in surface waters are toxic to aquatic life.

Total ammonia is the sum of both NH₃ (ammonia, the un-ionised form) and NH₄⁺ (ammonium, the ionised form). Total ammonia is what is measured analytically in water. Ammonia toxicity is influenced by pH and temperature, whereby an increase in either will convert more NH₄⁺ to NH₃, thereby increasing toxicity.