NECi Nitrate Testing Kits

*NECi Nitrate Testing Kits


The Nitrate Reductase method is a green, cadmium-free alternative to EPA method 353.2 for the reduction of nitrate to nitrite prior to analyses. Method N07-003 was designated as an EPA Alternative Test Protocol for Safe Drinking Water Act (SDWA) for nitrate determinations using discrete analyzers in July 2016.  On August 7th, 2017, the EPA granted NECi's Nitrate Reductase ATP status for Clean Water Act applications as part of the 2016 Methods Update Rule.  Regulation 40 CFR Part 136 allows method flexibility: the assay is compatible with virtually any type of colorimetric detection, for anything except drinking water.  The method is a green' alternative to the other approved methods which use cadmium, a known carcinogen, for the reduction of nitrate to nitrite prior to analyses. NECi Method N07-003 uses automated discreet analysis, flow injection analysis, or manual reagent additions and spectrophotometry to determine concentrations of nitrate and nitrite, combined or separately in wastewater. The method involves the following steps:

  • Enzymatic reduction of nitrate in a sample to nitrite using eukaryotic nitrate reductase;
  • Diazotizing the nitrite originally in the sample plus the reduced nitrate with sulfanilamide followed by coupling with N-(1-napthyl)ethylenediamine dihydrochloride under acidic conditions to form a highly colored azo dye;
  • Colorimetric determination in which the absorbance of color at 546 nm is directly proportional to the concentration of the nitrite plus the reduced nitrate in the sample;
  • Measurement of nitrite separately, if needed, by analysis of the sample while eliminating the reduction step;
  • Subtraction of the nitrite value from that of the combined nitrate -nitrite value to measure nitrate separately if needed.

Contact your regulators or auditors for information on how you can start using the method now.

Reagent packs are available for discrete or flow injection analyzers as well as manual addition. A separate reagent kit formulated especially for soil analysis is also available. For field screening, there is a portable handheld photometer operated via an Android app. 

Click here to watch the NECi webinar

Click here for NECi Product Sheet 

Automated Analyzer Reagent Packs

Item No. Description
NRPK-AP-1AT Astoria Pacific Low Range Analyzer Nitrate Reagent Pk
NRPK-DA-1AT Nitrate Reagent for Discrete Analyzers, 50 samples
NRPK-FIA-3AT Nitrate Reagent for Flow Injection Analyzers
NRPK-HDA-3AT Nitrate Reagent for High Capacity Discrete Analyzers
NRPK-SA-1AT Seal AQ2 Analyzer Nitrate Reagent Pack
NRPK-SC-1AT Smartchem Analyzer Nitrate Reagent Pack

Enzyme Assay Buffer

Item No. Description
E-ABN Assay Buffer for Nitrate Test, 50 mL, 2pk

Field Soil Testing Kits

Item No. Description
NTK-S-05 Field Soil Nitrate Test Kit, 5pk
NTK-S-10 Field Soil Nitrate Test Kit, 10pk
NTK-S-25 Field Soil Nitrate Test Kit, 25pk
NTK-S-50 Field Soil Nitrate Test Kit, 50pk

Field Water Testing Kits

Item No. Description
NTK-WLR-05 Field LR Water Nitrate Test Kit, 5pk
NTK-WLR-10 Field LR Water Nitrate Test Kit, 10pk
NTK-WLR-25 Field LR Water Nitrate Test Kit, 25pk
NTK-WLR-50 Field LR Water Nitrate Test Kit, 50pk
NTK-WSR-05 Field SR Water Nitrate Test Kit, 5pk
NTK-WSR-10 Field SR Water Nitrate Test Kit, 10pk
NTK-WSR-25 Field SR Water Nitrate Test Kit, 25pk
NTK-WSR-50 Field SR Water Nitrate Test Kit, 50pk

Test Tube Format Nitrate Testing Kits

Item No. Description
NTK-TTLR-100 Test Tube Format LR Nitrate Test Kit, 100pk


How long do Color Reagents 1 & 2 last after mixing?

Color reagent 1 is the acid/sulfanilamide reagent. It is good for 3 months. Color reagent 2 is the NED solution. This should be refrigerated and kept in an amber bottle. It is good until it becomes discolored.

Is it EPA approved? i.e. can I use it for compliance with my NPDES permit?

The U.S. EPA has issued ATP Case No. N07-0003 in 40 CFR part 136.3 for the use of Nitrate Reductase method for nitrate/nitrite analysis for CWA reporting. The Methods Update Rule, which contains all Alternate Test Procedures for this round, will most likely be promulgated by the end of 2016 if no major challenges are met. However, in the interim, a facility may apply to an EPA Region for a limited-use ATP approval letter for use at that facility.

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