ASTM_D_4130_-_15.pdf

Designation:D413015Standard Test Method forSulfate Ion in Brackish Water,Seawater,and Brines1This standard is issued under the fixed designation D4130;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 covers the turbidimetric determinationof sulfate ion in brackish water,seawater,and brines.It hasbeen used successfully with synthetic brine grade waters;however,it is the users responsibility to ensure the validity ofthis test method to other matrices.1.2 This test method is applicable to waters having an ionicstrength greater than 0.65 mol/Land a sulfate ion concentrationgreater than 25 mg/L.Aconcentration less than 25 mg/Lsulfatecan be determined by using a standard addition method.1.3 For brines having an ionic strength of less than 0.65mol/L,refer to Test Methods D516.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.2.Referenced Documents2.1 ASTM Standards:2D516 Test Method for Sulfate Ion in WaterD1129 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 ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible SpectrophotometersE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.4.Summary of Test Method4.1 A sulfate ion is converted to a barium sulfate suspendedunder controlled conditions.A glycerin-acid solution is addedto acidify and stabilize the suspension.A calculated volume ofa NaCl solution is added to adjust the ionic strength to a setvalue of 2 mol/L(Note 1).The turbidity resulting uponaddition of barium chloride is determined by a photoelectriccolorimeter and compared to a curve prepared from standardsulfate solutions.NOTE1The ionic strength(IS)of the sample is calculated from theconcentration of the major ion constituents(Na+,Ca2+,Mg2+,Cl),(K+and Sr2+if their concentration exceeds 2000 mg/L)as follows:where:IS,mol/L=1/2 CiZi2,Ci=g/L ion i/molecular weight ion,i,andZi=valence of ion i.5.Significance and Use5.1 The determination of sulfate and other dissolved con-stituents is important in identifying the source of brinesproduced during the drilling and production phases of crude oilor natural gas.6.Interferences6.1 Suspended matter in the sample must be removed.Darkcolors that cannot be compensated for in the procedureinterfere with the measurement of suspended barium sulfate(BaSO4).7.Apparatus7.1 PhotometerAfilter photometer or a spectrophotometerfor measurements between 400 to 450 nm,the preferablewavelength being 425 nm.The cell for the instrument musthave a light path of 20 6 2 mm and hold a volume of 25 mL.1This 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 Feb.1,2015.Published April 2015.Originallyapproved in 1982.Last previous edition approved in 2008 as D4130 08.DOI:10.1520/D4130-15.2For 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 States1 Filter photometers,spectrophotometers,and photometric prac-tices prescribed in this test method shall conform to PracticeE275.7.2 ThermometerAn ASTM Gravity Thermometer havinga range from 20 to+102C(or 5 to+215F),as specified,and conforming to the requirements for Thermometer ASTM12C(or ASTM 12F),respectively,as prescribed in Specifica-tion E2251.8.Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,providing