ASTM_D_511_-_14.pdf

Designation:D51114Standard Test Methods forCalcium and Magnesium In Water1This standard is issued under the fixed designation D511;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 These test methods cover the determination of calciumand magnesium in water by complexometric titration andatomic absorption spectrometric procedures.Two test methodsare included,as follows:SectionsTest Method AComplexometric Titration7 15Test Method BAtomic Absorption Spectrometric16 251.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversion to inch-pound units that are provided for informa-tion only and are not considered standard.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.Specific hazardstatements are given in 12.2.6 and 20.6.2.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 ConduitsD4691 Practice for Measuring Elements in Water by FlameAtomic Absorption SpectrophotometryD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods,refer to Terminology D1129.4.Significance and Use4.1 Calcium and magnesium salts in water are the primarycomponents of water hardness which can cause pipe or tubescaling.5.Purity of Reagents5.1 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 Society.3Other gradesmay be used,provided it is first ascertained that the reagent isof sufficiently high purity to permit its use without lesseningthe accuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Specification D1193,Type 1,II,or III water.Type I ispreferred and more commonly used.Type II water wasspecified at the time of round-robin testing of these testmethods.NOTE1The user must ensure the type of reagent water is sufficientlyfree of interferences.The water should be analyzed using this test method.6.Sampling6.1 Collect the sample in accordance with Practices D3370.6.2 If total recoverable calcium and magnesium concentra-tions are being determined,acidify the water sample withHNO3(sp gr 1.42)to a pH of 2 or less immediately at the timeof collection;normally about 2 mL/L are required.The holdingtime for the samples may be calculated in accordance withPractice D4841.1These 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 Oct.1,2014.Published November 2014.Originallyapproved in 1937.Last previous edition approved in 2009 as D511 09.DOI:10.1520/D0511-14.2For 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.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For Suggestions on the testing of reagents notlisted by the American Chemical Society,see Annual Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.*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 NOTE2Alternatively,the pH may be adjusted in the laboratory if thesample is returned within 14 days.However,acid must be added at least24 hours before analysis to dissolve any metals that adsorb to the containerwalls.This could reduce hazards of working with acids in the field whenappropriate.6.3 If dissolved calcium and magnesium concentrations arebeing determined,filter the samples through a 0.45-m mem-brane filter and acidify with HNO3(sp gr 1.4