ASTM_D_6919_-_09.pdf

Designation:D691909Standard Test Method forDetermination of Dissolved Alkali and Alkaline EarthCations and Ammonium in Water and Wastewater by IonChromatography1This standard is issued under the fixed designation D6919;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 This test method is valid for the simultaneous determi-nation of the inorganic alkali and alkaline earth cations,lithium,sodium,potassium,magnesium,and calcium,as wellas the ammonium cation in reagent water,drinking water,andwastewaters by suppressed and nonsuppressed ion chromatog-raphy.1.2 The anticipated range of the method is 0.05200 mg/L.The specific concentration ranges tested for this method foreach cation were as follows(measured in mg/L):Lithium0.410.0Sodium4.040.0Ammonium0.410.0Potassium1.220.0Magnesium2.420.0Calcium4.040.01.2.1 The upper limits may be extended by appropriatedilution or by the use of a smaller injection volume.In somecases,using a larger injection loop may extend the lower limits.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 It is the users responsibility to ensure the validity ofthese test methods for waters of untested matrices.1.5 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.For hazardsstatements specific to this test method,see 8.3.2.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 WaterD3370 Practices for Sampling Water from Closed ConduitsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4210 Practice for Intralaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data(Withdrawn 2002)3D5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD5905 Practice for the Preparation of Substitute Wastewater3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.4.Summary of Test Method4.1 Inorganic cations and the ammonium cation,hereafterreferred to as ammonium,are determined by ion chromatog-raphy in water and wastewater samples from a fixed samplevolume,typically 1050 L.The cationic analytes are sepa-rated using a cation-exchange material,which is packed intoguard and analytical columns.Adilute acid solution is typicallyused as the eluent.4.1.1 The separated cations are detected by using conduc-tivity detection.To achieve sensitive conductivity detection,it1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved May 15,2009.Published May 2009.Originallyapproved in 2003.Last previous edition approved in 2003 as D6919 03.DOI:10.1520/D6919-09.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.*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 is essential that the background signal arising from the eluenthave low baseline noise.One means to achieve low back-ground noise is to combine the conductivity detector with asuppressor device that will reduce the conductance of theeluent,hence background noise,and also transform the sepa-rated cations into their more conductive corresponding bases.44.1.2 Detection can also be achieved without chemicalsuppression,whereby the difference between the equivalentionic conductance of the eluent and analyte cation is measureddirectly after the analytical column.This test method willconsider both suppressed and nonsuppressed detection tech-nologies.The conductivity data is plotted to produce a chro-matogram that is used to determine peak areas.A chromato-graphic integrator or appropriate computer-based data systemis typically used for data presentation.4.2 The cations are identified based on their retention timescompared to known standards.Quantification is accomplishedby measuring cation peak areas and comparing them to theareas generated from known standards.The result