ASTM_D_2973_-_10e1.pdf

Designation:D2973101Standard Test Method forTotal Nitrogen in Peat Materials1This standard is issued under the fixed designation D2973;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorially corrected the jurisdiction in March 2011.1.Scope*1.1 This test method covers a chemical test method2for thedetermination of the weight percent of nitrogen in peatmaterial.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.(See PracticeD3740)2.Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil,Rock,and ContainedFluidsD1193 Specification for Reagent WaterD2974 Test Methods for Moisture,Ash,and Organic Matterof Peat and Other Organic SoilsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4753 Guide for Evaluating,Selecting,and Specifying Bal-ances and Standard Masses for Use in Soil,Rock,andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 Definitions:3.1.1 For common definitions of terms in this standard,referto Terminology D653.4.Summary of Test Method4.1 In this procedure,the nitrogen is converted into ammo-nium salts by destructive digestion of the sample with a hot,catalyzed mixture of concentrated sulfuric acid and potassiumsulfate.These salts are subsequently decomposed in a hotalkaline solution from which the ammonia is recovered bydistillation and finally determined by acidimetric titration.5.Significance and Use5.1 Nitrogen content is important as it is one of the primaryplant food elements necessary for plant growth.Nitrogen ispresent in peat as organic nitrogen,and therefore,does notrelease nitrogen to plants as quickly as chemical fertilizers.However,nitrogen from peat continues to be released forseveral years as the organic matter decomposes.6.Apparatus6.1 For DigestionUse Kjeldahl flasks of hard,moderatelythick,well-annealed glass with total capacity of about 800 mL.Conduct digestion over a heating device adjusted to bring 250mL of water at 25C to a rolling boil in about 5 min.6.2 For DistillationUse 800-mL Kjeldahl flasks fittedwith rubber stoppers through which passes the lower end of anefficient scrubber bulk or trap to prevent mechanical carry-overof sodium hydroxide solution during distillation.Connect theupper end of the bulb tube to the condenser tube by rubbertubing.Trap the outlet of the condenser in such a way as toensure complete absorption of ammonia distilled over into theacid in the receiver.6.3 Erlenmeyer Flask,250 or 300-mL capacity.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended that1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.22 on Soil as a Mediumfor Plant Growth.Current edition approved Oct.1,2010.Published November 2010.Originallyapproved in 1971.Last previous edition approved in 2004 as D297371(2004).Withdrawn in 2009 and reinstated in 2010 as D297310.DOI:10.1520/D2973-10e1.2This method is currently undergoing an extensive review byASTM CommitteeD18 and additional alternative methods will be proposed.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.All water used for this testmethod shall be ASTM Type III or better as defined inSpecification D1193.7.2 Boric Acid Solution,4%(40 g/L)Dissolve 40 g ofboric acid(H3BO3)in water and dilute to 1 L.7.3 Mercuric Oxide Tablets(HgO).7.4 Mixed IndicatorDissolve 200 mg of methyl red in 100mL of alcohol.Dissolve 200 mg methylene blue in 100 mL ofalcohol.Mix in