Standard Methods: 4500-NO₃- F: Nitrate by Automated Cadmium Reduction Method

Summary
Analytes
Revisions
Data and Sites

Official Method Name

4500-NO₃- F. Automated Cadmium Reduction Method

Current Revision

Standard Methods Online

Media

WATER

Instrumentation

Automated Spectrophotometer

Method Subcategory

Inorganic

Method Source

Standard Methods

Citation

Standard Methods Online - Standard Methods for the Examination of Water and Wastewater

Brief Method Summary

Nitrate is reduced almost quantitatively to nitrite in the presence of Cd. The nitrite thus produced is determined by diazotizing with sulfanilamide and coupling with N-(1-napthyl)-ethylenediamine dihydrochloride to form a highly colored azo dye that is measured colorimetrically.

Scope and Application

Nitrate and nitrite, singly or together in potable, surface, and saline waters and domestic and industrial wastewaters, can be determined over a range of 0.5 to 10 mg N/L.

Applicable Concentration Range

0.5 to 10 mg-N/L

Interferences

Sample turbidity may interfere. Remove by filtration before analysis. Sample color that absorbs in the photometric range used for analysis also will interfere.

Quality Control Requirements

See Section 4020 Quality Assurance/Quality Control.

Sample Handling

Plastic or glass containers. Start nitrate determinations promptly after sampling. If storage is necessary, store for up to 2 days at 4 degrees C ; disinfected samples are stable much longer (at least 14 days) without acid preservation (See 4500-NO3- A).

Maximum Holding Time

48 hours (general); 14 days (disinfected) (See 4500-NO3- A)

Relative Cost

Less than $50

Sample Preparation Methods

This method has 3 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Nitrate(14797-55-8) Nitrate Nitrate ion Nitrate-N Nitrates/nitrites Nitrogen, nitrate	0.500 mg/L	96% Rec	4.00 RSD	0.29 mg/L
Nitrate/nitrite(E-10128) NO2+NO3 NO2/NO3 NO3+NO2 Nitrate + nitrite Nitrate plus nitrite Nitrate+nitrite Nitrate/nitrite Nitrite + nitrate Nitrite+nitrate	N/A	N/A	N/A
Nitrite(14797-65-0) Nitrite Nitrite (as ion) Nitrite nitrogen Nitrite-N Nitrites Nitrogen, nitrite	N/A	N/A	N/A

Precision Descriptor Notes:	Data obtained in three laboratories with an automated system based on identical chemical principles but having slightly different configurations are given in a table in the method. Analyses were conducted on four natural water samples containing exact increments of inorganic nitrate. In a single laboratory using surface water samples at concentrations of 100, 200, 800, and 2100 ug N/L, the standard deviations were 0, +/-40, +/-50, and +/- 50 ug/L, respectively, and at concentrations of 200 and 2200 ug N/L, recoveries were 100 and 96%, respectively.
Detection Level Note:	Lowest level of stated method range.

Precision Descriptor Notes:

Data obtained in three laboratories with an automated system based on identical chemical principles but having slightly different configurations are given in a table in the method. Analyses were conducted on four natural water samples containing exact increments of inorganic nitrate. In a single laboratory using surface water samples at concentrations of 100, 200, 800, and 2100 ug N/L, the standard deviations were 0, +/-40, +/-50, and +/- 50 ug/L, respectively, and at concentrations of 200 and 2200 ug N/L, recoveries were 100 and 96%, respectively.

Detection Level Note:

Lowest level of stated method range.

Revision	PDF/Link
Standard Methods Online
Standard Methods 18th Edition (1992)
Standard Methods 19th Edition (1995)
Standard Methods 20th Edition (1998)

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Standard Methods: 4500-NO₃- F: Nitrate by Automated Cadmium Reduction Method

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Standard Methods: 4500-NO3- F: Nitrate by Automated Cadmium Reduction Method

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Standard Methods: 4500-NO₃- F: Nitrate by Automated Cadmium Reduction Method