ASTM D3867-16(2021)e1
(Test Method)Standard Test Methods for Nitrite-Nitrate in Water
Standard Test Methods for Nitrite-Nitrate in Water
SIGNIFICANCE AND USE
5.1 Both test methods use identical reagents and sample processing. The only difference between the two methods is that one test method is automated and the other is manual. The ranges and interferences are identical.
5.2 The automated test method is preferred when large numbers of samples are to be analyzed. The manual test method is used for fewer samples or when automated instrumentation is not available.
5.3 These test methods replace Test Methods D1254 (Nitrite) and D992 (Nitrate). The nitrite test method (Test Method D1254) used a reagent that is considered to be a potential carcinogen. The nitrate test method (Test Method D992) has been shown to have relatively large errors when used in wastewaters and also has greater manipulative difficulties than the test method described herein.
5.4 Test Method D7781 uses a nitrate reductase enzyme for the reduction of nitrate to nitrite. Cadmium is considered a toxic metal. Also, the heterogeneous cadmium reductant creates greater difficulty than the reduction described in this test method.
SCOPE
1.1 These test methods cover the determination of nitrite nitrogen, nitrate nitrogen, and combined nitrite-nitrate nitrogen in water and wastewater in the range from 0.05 to 1.0 mg/L nitrogen. Two test methods2 are given as follows:
Sections
Test Method A—Automated Cadmium Reduction
9 to 18
Test Method B—Manual Cadmium Reduction
19 to 28
1.2 These test methods are applicable to surface, saline, waste, and ground waters. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.3 The values stated in either SI or inch-pound units are to be regarded as the standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 8.2.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D3867 − 16 (Reapproved 2021)
Standard Test Methods for
Nitrite-Nitrate in Water
This standard is issued under the fixed designation D3867; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—The WTO caveat was editorially added and warning notes were editorially updated throughout in November
2021.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the determination of nitrite
D992 Method of Test for Nitrate Ion in Water (Withdrawn
nitrogen, nitrate nitrogen, and combined nitrite-nitrate nitrogen
1983)
in water and wastewater in the range from 0.05 to 1.0 mg/L
D1129 Terminology Relating to Water
nitrogen. Two test methods are given as follows:
D1141 Practice for Preparation of Substitute Ocean Water
Sections
D1193 Specification for Reagent Water
Test Method A—Automated Cadmium Reduction 9 to 18
Test Method B—Manual Cadmium Reduction 19 to 28 D1254 Method of Test for Nitrite Ion in Water (Withdrawn
1980)
1.2 These test methods are applicable to surface, saline,
D2777 Practice for Determination of Precision and Bias of
waste, and ground waters. It is the user’s responsibility to
Applicable Test Methods of Committee D19 on Water
ensure the validity of these test methods for waters of untested
D3370 Practices for Sampling Water from Flowing Process
matrices.
Streams
D5810 Guide for Spiking into Aqueous Samples
1.3 The values stated in either SI or inch-pound units are to
D5847 Practice for Writing Quality Control Specifications
be regarded as the standard. No other units of measurement are
for Standard Test Methods for Water Analysis
included in this standard.
D7781 Test Method for Nitrite-Nitrate in Water by Nitrate
1.4 This standard does not purport to address all of the
Reductase
safety concerns, if any, associated with its use. It is the
E60 Practice for Analysis of Metals, Ores, and Related
responsibility of the user of this standard to establish appro-
Materials by Spectrophotometry
priate safety, health, and environmental practices and deter-
E275 Practice for Describing and Measuring Performance of
mine the applicability of regulatory limitations prior to use.
Ultraviolet and Visible Spectrophotometers
For specific hazard statements, see 8.2.
3. Terminology
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1 Definitions:
ization established in the Decision on Principles for the
3.1.1 For definitions of terms used in this standard, refer to
Development of International Standards, Guides and Recom-
Terminology D1129.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Summary of Test Methods
4.1 Total Oxidized Nitrogen—A filtered sample is passed
through a column containing copper-coated cadmium granules
to reduce nitrate ion to nitrite ion. The combined nitrite-nitrate
nitrogen is determined by diazotizing the total nitrite ion with
These test methods are under the jurisdiction of ASTM Committee D19 on
Water and are the responsibility of Subcommittee D19.05 on Inorganic Constituents
in Water. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2021. Published December 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1979. Last previous edition approved in 2016 as D3867 – 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D3867-16R21E01. the ASTM website.
2 4
Methods similar to these appear in Methods of Chemical Analysis of Water and The last approved version of this historical standard is referenced on
Wastes, 2nd edition, U.S. Environmental Protection Agency. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D3867 − 16 (2021)
sulfanilamide and coupling with N-(1- The use of chlorine-containing Type II water will lead to a
naphthyl)ethylenediamine dihydrochloride to form a highly negative interference because nitrite and chlorine do not
colored azo dye that is measured spectrophotometrically. normally coexist. This is of particular importance when pre-
paring standards or spiked samples (Guide D5810).
4.2 Nitrite—The nitrite ion originally present in the sample
canbedeterminedseparatelybycarryingouttheprocedureand
6.6 In acid samples (pH less than 4.5) nitrate is not reduced
omitting the cadmium reduction step.
in the cadmium column. To overcome this interference, the
sample must be neutralized to a pH of between 6 and 8 prior to
4.3 Nitrate—The nitrate ion can be calculated as the differ-
analysis.
ence between the combined nitrite-nitrate nitrogen and the
nitrite nitrogen.
7. Purity of Reagents
5. Significance and Use
7.1 Reagent grade chemicals shall be used in all tests.
Unless otherwise indicated, it is intended that all reagents shall
5.1 Both test methods use identical reagents and sample
processing. The only difference between the two methods is conform to the specifications of the Committee on Analytical
Reagents of the American Chemical Society, when such
that one test method is automated and the other is manual. The
ranges and interferences are identical. specifications are available. Other grades may be used, pro-
vided it is first ascertained that the reagent is of sufficient high
5.2 The automated test method is preferred when large
purity to permit its use without lessening the accuracy of the
numbers of samples are to be analyzed. The manual test
determination.
method is used for fewer samples or when automated instru-
mentation is not available.
7.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water conforming
5.3 These test methods replace Test Methods D1254 (Ni-
to Specification D1193, Type I. Other reagent water types may
trite) and D992 (Nitrate). The nitrite test method (Test Method
be used, provided it is first ascertained that the water is of
D1254) used a reagent that is considered to be a potential
sufficiently high purity to permit its use without adversely
carcinogen. The nitrate test method (Test Method D992) has
affecting the bias and precision of these test methods. Type II
been shown to have relatively large errors when used in
water was specified at the time of round-robin testing of these
wastewaters and also has greater manipulative difficulties than
test methods.
the test method described herein.
5.4 Test Method D7781 uses a nitrate reductase enzyme for
8. Sampling and Sample Preservation
the reduction of nitrate to nitrite. Cadmium is considered a
8.1 Collect the sample in accordance with Practices D3370.
toxic metal. Also, the heterogeneous cadmium reductant cre-
ates greater difficulty than the reduction described in this test
8.2 When nitrite ion is to be determined separately, analyze
method.
as soon as possible after sampling. Even when sterile bottles
are used, bacteria naturally present in the water may cause
6. Interferences
conversion of all or part of nitrite ion to other forms such as
6.1 Turbid samples must be filtered prior to analysis to
nitrate or ammonia. Ammonia and natural amines, which are
eliminate particulate interference. Furthermore, sample turbid-
frequently present in natural waters, may react with nitrites to
ity results in a buildup on the reduction column that restricts
form nitrogen. If samples are to be stored for 24 h or less,
sample flow.
preserve the sample by refrigeration at 4°C. If the sample must
be stored for more than 24 h, preserve it by the addition of 2
6.2 Sample color that absorbs at wavelengths between 520
mL of chloroform per litre (11.7 and 11.9) in addition to
and 540 nm interferes with the absorbance measurements.
refrigeration at 4°C. (Warning—Chloroform is toxic and is a
When color is suspect, analyze a sample blank, omitting the
suspected human carcinogen. Use with adequate ventilation or
N-(1-naphthyl)ethylenediamine dihydrochloride from the color
in a fume hood. Wear prescribed protective equipment. Use of
reagent.
chloroform is discouraged, since its use renders the solution a
6.3 Oil and grease in the sample coat the surface of the
hazardous waste.) (Caution—The common prescribed use of
cadmium and prevent complete reduction of nitrate to nitrite.
sulfuric acid or mercury compounds as preservatives is dis-
This interference is usually removed by filtration prior to
couraged. Sulfuric acid does not necessarily inhibit oxidation
analysis. If filtration is not adequate, the interference can be
and mercury compounds should be avoided to prevent envi-
removed by extracting the sample with an n-hexane or a solid
ronmental pollution. Mercuric chloride is known to deactivate
phase extraction (SPE) filter.
the column.)
6.4 Certain metal ions, in concentrations above 35 mg/L,
may cause interferences. For example, Hg (II) and Cu (II) may
form colored complex ions having absorption bands in the
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
region of color measurement. Iron and manganese are other
Standard-Grade Reference Materials, American Chemical Society, Washington,
reported examples of interference. DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
6.5 Excessiveamountsofchlorinewilldeactivatethereduc-
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
ing column. Chlorine might be present in some Type II water. copeial Convention, Inc. (USPC), Rockville, MD.
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D3867 − 16 (2021)
FIG. 1 Nitrite-Nitrate Manifold
TEST METHOD A—AUTOMATED CADMIUM 10.2 Reduction Columns—Choosetheappropriatereduction
REDUCTION column for the manifold system. A schematic drawing of the
manifold system is shown in Fig. 1 and the cartridge system is
9. Scope shown in Fig. 2.
10.2.1 Reduction Column, a glass tube 8 by 50 mm with the
9.1 The applicable range of this test method is from 0.05 to
ends reduced in diameter to permit insertion into the system
1 mg/L of nitrite or nitrate nitrogen. The range may be
(see Fig. 1).
extended upward by dilution of an appropriate aliquot. Many
10.2.2 Reduction Column, a U-shaped glass tubing,
workers have found that this test method is reliable for nitrite
350-mm length and 2-mm inside diameter.
and combined nitrite-nitrate levels to 0.01 mg N/L. However,
the precision and bias data presented in this test method are
NOTE 1—Apump tube with 0.081-in. (2.1-mm) inside diameter can be
used in place of the 2-mm glass tube.
insufficient to justify application of this test method in the 0.01
to 0.05 mg/L-N range.
11. Reagents and Materials
9.2 This test method is applicable to surface, saline, waste,
11.1 Ammonium Chloride Solution (85 g/L)—Dissolve 85 g
and ground waters. It is the user’s responsibility to ensure the
ofammoniumchloride(NH Cl)inwateranddiluteto1L.Add
validity of this test method for waters of untested matrices.
0.5 mL wetting agent.
10. Apparatus
11.2 Cadmium, 40 to 60 mesh, granulated.
10.1 Automated Analysis System consisting of:
11.3 ColorReagent—Addthefollowingto800mLofwater,
10.1.1 Sampler.
while stirring constantly: 100 mL of concentrated phosphoric
10.1.2 Manifold or Analytical Cartridge.
acid (H PO ), 10 g of sulfanilamide, and 0.5 g of N-1-
3 4
10.1.3 Colorimeter equipped with a 15- or 50-mm tubular
(naphthyl)ethylenediamine dihydrochloride. Stir until dis-
flow cell and 540 6 10-nm filters.
solved. Add 1 mL of wetting agent, and dilute to 1 L with
10.1.4 Recorder or Electronic Data Acquisition Device.
water. This solution is stable for about a month when stored in
10.1.5 Digital Printer (Optional).
a brown bottle in a dark cool place.
10.1.6 Continuous Filter (Optional).
A 30 % aqueous solution of Brij 35, a polyoxyethylene compound with
The apparatus described is commercially available. ASTM does not undertake dodecyl alcohol (sp gr 1.18 to 1.22) has been found satisfactory for this purpose.
to ensure anyone utilizing an automated analysis system against liability of Different sizes of granulated cadmium may be used. The analyst should ensure
infringement of patent or assume such liability. that adequate reduction occurs with the size chosen.
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D3867 − 16 (2021)
FIG. 2 Nitrite-Nitrate Cartridge
NOTE 2—Potassium nitrite is easily oxidized, so use only fresh bottles
11.4 Copper Sulfate Solution (20 g/L)—Dissolve 20 g of
of this reagent.
copper sulfate pentahydrate (CuSO ·5H O) in 500 mL of
4 2
water. Dilute to 1 L. 11.10 Nitrite Solution, Standard (1.0 mL = 0.01 mg
NO –N)—Dilute 10 mL of stock nitrite solution (11.9)to1L
11.5 n-Hexane.
with water. This solution is unstable; prepare fresh as needed.
11.6 Hydrochloric Acid (1+1)—Slowly add 50 mL of
11.11 Filter Paper—Purchase suitable filter paper.Typically
concentrated hydrochloric acid (HCl) to 40 to 45 mL of water
the filter papers have a pore size of 0.45-µm membrane.
and dilute to 100 mL.
Material such as fine-textured, acid-washed, ashless paper, or
11.7 Nitrate Solution, Stock (1.0 mL = 1.0 mg NO -N)—
glass fiber paper are acceptable. The user must first ascertain
Dry potassium nitrate (KNO ) in an oven at 105°C for 24 h.
that the filter paper is of sufficient purity to use without
Dissolve 7.218 g in water in a 1-L volumetric flask. Dilute to
adversely affecting the bias and precision of the test method.
the mark with water. This solution is stable for up to 1 month
withrefrigeration.Iflongerstabilityisrequiredorrefrigeration
12. Preparation of Reduction Column
is not available, add 2 mL of chloroform as a preservative and
12.1 Cadmium Granules Treatment—Clean and copperize
store in a dark bottle. This solution is stable for 6 months. (See
new or used cadmium granules in the following manner:
8.2.)Alternatively,certifiednitratestocksolutionsarecommer-
12.1.1 Clean about 10 g of cadmium granules (11.2)by
cially available through chemical supply vendors and may be
used. washing with dilute HCl (11.6) and rinsing with water.
12.1.2 Swirl the clean cadmium in 100-mL portions of
11.8 Nitrate Solution, Standard (1.0 mL = 0.01 mg NO -
copper sulfate solution (11.4) in a beaker for 5
...
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