6/12/14 -- NECi enzymatic method for nitrate determination is now an ASTM International Standard Method. This method is meant to replace methods D1254 (Nitrite) and D992 (Nitrate).
Method D1254 uses a reagent which is considered to be a possible carcinogen. Method D992 is mentioned by ASTM to 'have relatively large errors when used in wastewaters and also has greater manipulative difficulties' than the [enzymatic] method'. This test method may be used instead of Test Methods D3867 (Nitrate-Nitrite) which use cadmium, a toxic heavy metal.
'This method is applicable for the determination of nitrate plus nitrite (as nitrogen) in drinking water, surface, saline, wastewater, and ground waters'-ASTM Scope 1.1 Method D7781 - 14
The range of this method is from 0.05 mg/L up to 5 mg/L of nitrogen but may be extended or narrowed by dilution or sample volume alteration.
Please contact The Nitrate Elimination Company, Inc. (NECi) for more information.