ASTM D2973-71(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D2973–71(Reapproved 2004)
Standard Test Method for
Total Nitrogen in Peat Materials
This standard is issued under the fixed designation D 2973; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 5. Apparatus
1.1 This test method covers a chemical test method for the 5.1 For Digestion—Use Kjeldahl flasks of hard, moderately
determination of the weight percent of nitrogen in peat thick, well-annealed glass with total capacity of about 800 mL.
material. Conduct digestion over a heating device adjusted to bring 250
1.2 This standard does not purport to address all of the mL of water at 25°C to a rolling boil in about 5 min.
safety concerns, if any, associated with its use. It is the 5.2 For Distillation—Use 800-mL Kjeldahl flasks fitted
responsibility of the user of this standard to establish appro- with rubber stoppers through which passes the lower end of an
priate safety and health practices and determine the applica- efficient scrubber bulk or trap to prevent mechanical carry-over
bility of regulatory limitations prior to use. of sodium hydroxide solution during distillation. Connect the
upper end of the bulb tube to the condenser tube by rubber
2. Referenced Documents
tubing. Trap the outlet of the condenser in such a way as to
2.1 ASTM Standards: ensure complete absorption of ammonia distilled over into the
D 2974 Test Methods for Moisture, Ash, and Organic Mat-
acid in the receiver.
ter of Peat and Other Organic Soils 5.3 Erlenmeyer Flask, 250 or 300-mL capacity.
3. Summary of Test Method
6. Reagents
3.1 In this procedure, the nitrogen is converted into ammo- 6.1 Purity of Reagents—Reagent grade chemicals shall be
nium salts by destructive digestion of the sample with a hot,
used in all tests. Unless otherwise indicated, it is intended that
catalyzed mixture of concentrated sulfuric acid and potassium all reagents shall conform to the specifications of the Commit-
sulfate. These salts are subsequently decomposed in a hot
tee onAnalytical Reagents of theAmerican Chemical Society,
alkaline solution from which the ammonia is recovered by where such specifications are available. Other grades may be
distillation and finally determined by acidimetric titration. used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
4. Significance and Use
accuracy of the determination.
4.1 Nitrogen content is important as it is one of the primary
6.2 Boric Acid Solution, 4 % (40 g/L)—Dissolve 40 g of
plant food elements necessary for plant growth. Nitrogen is
boric acid (H BO ) in water and dilute to 1 L.
3 3
present in peat as organic nitrogen, and therefore, does not
6.3 Mercuric Oxide Tablets (HgO).
release nitrogen to plants as quickly as chemical fertilizers.
6.4 Mixed Indicator—Dissolve200mgofmethylredin100
However, nitrogen from peat continues to be released for
mL of alcohol. Dissolve 200 mg methylene blue in 100 mL of
several years as the organic matter decomposes.
alcohol.Mixinaratioof1partmethylredto2partsmethylene
blue.
6.5 Potassium Sulfate (K SO ).
2 4
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
6.6 Potassium Sulfide Solution (40 g/L)—Dissolve 40 g of
RockandisthedirectresponsibilityofSubcommitteeD18.06onPhysical-Chemical
potassium sulfide in water and dilute to 1 L.
Interactions of Soil and Rock.
Current edition approved July 1, 2004. Published July 2004. Originally approved
in 1971. Last previous edition approved in 1998 as D 2973 - 71 (1998).
2 4
This method is currently undergoing an extensive review byASTM Committee Reagent Chemicals, American Chemical Society Specifications, American
D18 and additional alternative methods will be proposed. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Annual Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Phar
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