ASTM_D_3590_-_17.pdf

Designation:D359017Standard Test Methods forTotal Kjeldahl Nitrogen in Water1This standard is issued under the fixed designation D3590;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.1.Scope*1.1 These test methods cover the determination of totalKjeldahl nitrogen.Section 24 on Quality Control pertains tothese test methods.The following test methods are included:SectionsTest Method AManual Digestion/Distillation8 14Test Method BSemiautomated Colorimetric Bertholt15 231.2 The analyst should be aware that precision and biasstatements included may not necessarily apply to the waterbeing tested.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1426 Test Methods for Ammonia Nitrogen In WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 continuing calibration blank,na solution containingno analytes(of interest)which is used to verify blank responseand freedom from carryover.3.2.2 continuing calibration verification,na solution(orset of solutions)of known concentration used to verify freedomfrom excessive instrumental drift;the concentration is to coverthe range of calibration curve.3.2.3 total Kjeldahl nitrogen,nthe sum of the nitrogencontained in the free ammonia and other nitrogen compounds,which are converted to ammonium sulfate(NH4)2SO4 underthe specified digestion conditions.4.Significance and Use4.1 These test methods are useful for measuring organicnitrogen and ammoniacal nitrogen,which are essential growthnutrients.4.2 Nitrogen compounds are widely distributed in the envi-ronment.Sources of nitrogen include surface-appliedfertilizers,cleaning products,and drinking water treatmentaids.Because nitrogen is a nutrient for photosyntheticorganisms,it may be important to monitor and control dis-charge into the environment.5.Interferences5.1 Nitrate is known to cause a serious negative interferencein the test.Reportedly,a concentration of 250 mg/L NO3results in zero recovery of some level of mg/LN added as somenitrogen compound.5.2 The analyst is cautioned that ammonia in the laboratorymay easily become an interference in these test methods fromcontamination of reagents,caps,or from the laboratory atmo-sphere.Care should be taken that ammonium hydroxide,eitheras a reagent or as a cleaning substance,is not used in the sameroom.1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved June 1,2017.Published June 2017.Originallyapproved in 1977.Last previous edition approved in 2011 as D3590 11.DOI:10.1520/D3590-17.2For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 6.Purity of Reagents6.1 Reagent-grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical