ASTM_D_8001_-_16e1.pdf

Designation:D8001161Standard Test Method forDetermination of Total Nitrogen,Total Kjeldahl Nitrogen byCalculation,and Total Phosphorus in Water,Wastewater byIon Chromatography1This standard is issued under the fixed designation D8001;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.1NOTEEditorial changes were made throughout in September 2016.1.Scope1.1 This test method is applicable for the analysis totalnitrogen(organic nitrogen+ammonia-N+nitrate-N+nitrite-N)as nitrate and total phosphorus as orthophosphate inunfiltered water samples by alkaline persulfate digestion fol-lowed by ion chromatography(IC).1.2 Total Kjeldahl nitrogen(TKN)is determined by thecalculation.To determine TKN subtract the nitrate-N andnitrite-N in a digested sample from a non-digested sample(seeSection 4,Summary of Test Method).1.3 The limit of detection(LOD),limit of quantitation(LOQ),and reporting range in Table 1 are based on thetwo-step process for this test method:digestion and analyticalstep.Because the digestion step requires a sample dilution,theLOD and LOQ are higher than undigested samples.Thereporting range,LOD,and LOQ can be modified and perhapsimproved depending on several factors(see Section 6,Inter-ferences).1.4 The method detection limits(MDL)are shown forreference.The digestion reagent contains background nitrateand results in higher detection limits.MDL will be shown afterthe interlaboratory study(ILS)is completed.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4327 Test Method for Anions in Water by Suppressed IonChromatographyD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD5810 Guide for Spiking into Aqueous SamplesD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3.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 total Kjeldahl nitrogen(TKN),nthe sum of organicnitrogen plus ammonia(NH3).3.2.2 total nitrogen(TN),nthe sum of all nitrate,nitrite,ammonia,and organic nitrogen,as N,in water or wastewatersamples.3.2.3 totalphosphorus(TP),nthesumoforthophosphates,polyphosphates,and organically boundphosphates,as P,in water or wastewater samples.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved July 15,2016.Published August 2016.DOI:10.1520/D8001-16E01.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Method4.1 A water sample is digested with alkaline persulfate at a2:1 ratio,the initial pH is 12.This sample is heated at 120Cfor 60 min.Initial alkaline conditions oxidize dissolved/suspended nitrogen to nitrate.Over time the solution becomesacidic according to the following calculation:S2O8221H2O2HSO42112O2(1)The acidic conditions(pH 2)result in the hydrolysis ofdissolved/suspended phosphorus to orthophosphate.4.2 The determinative step using IC is equivalent to TestMethod D4327.5.Significance and Use5.1 This test method allows the simultaneous determinationof total nitrogen and total phosphorous from one sampledigestion step.5.2 This test method measures oxidized ammonia and or-ganic nitrogen(as nitrate)and soluble nitrate simultaneously.By subtracting the nitrate+nitrite value from a non-digestedsample gives a TKN:TN5 TKN1NO3-N!1NO2-N!(2)TKN5 NH3-N1Organic N(3)When using this test method:TKN5 Digested Sample2 Non-Digested Sample(4)TKN5 TN2NO3-N 1 NO2-N#(5)where:TN=total nitrogen,andTKN=total Kjeldahl nitrogen.6.Interferences6.1 Interf