ASTM_D_3986_-_11.pdf

Designation:D398611Standard Test Method forBarium in Brines,Seawater,and Brackish Water by Direct-Current Argon Plasma Atomic Emission Spectroscopy1This standard is issued under the fixed designation D3986;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 determination of dissolvedand total recoverable barium in brines,seawater,and brackishwaters by direct-current argon plasma atomic emission spec-troscopy(DCPAES).1.2 This test method has been tested in the range from 10mg/L to 20 mg/L.Samples shall be diluted to contain concen-trations within the calibration range(see 11.1 and 12.5).Higherconcentrations can also be determined by changing to a lesssensitive emission line.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.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD3352 Test Method for Strontium Ion in Brackish Water,Seawater,and BrinesD3370 Practices for Sampling Water from Closed ConduitsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisE1097 Guide for Direct Current Plasma-Atomic EmissionSpectrometry Analysis3.Terminology3.1 DefenitionsFor definitions of terms used in this testmethod refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 total recoverable barium,nrecoverable bariumforms that are determinable by the digestion method that isincluded in the procedure.3.2.2 laboratory control sample,na solution with a certi-fied concentration of barium.4.Summary of Test Method4.1 This test method is dependent upon excitation of thebarium atom by a direct-current plasma source.When theexcited barium atom decays to a lower energy state it emitsenergy of a wavelength characteristic to the barium atom.Theintensity of this emitted radiation will increase in directproportion to the concentration of barium in the sample,whenworking in the linear response range.4.2 Since the variable and often high concentration ofmatrix materials in brines,seawater,and brackish water affectemission differently,it is a difficult task to prepare standardssufficiently similar to the samples.To overcome this problem,the standards are buffered with lithium ion and the samples arediluted and buffered in the same manner.The standards areused to construct a calibration curve and the concentration ofthe samples are calculated from this curve.Alternatively,theinstrument may be calibrated using a blank and a standard orbracketing standards.The sample concentration can then beread out directly from the instrument.4.3 The 455.4-nm line has been found to be the mostsatisfactory for analysis.NOTE1The barium lines at 230.4 nm,233.5 nm,and 553.6 nm havebeen checked and found to be unsatisfactory for this analysis.4.4 Dissolved barium is determined by filtering the samplethrough a 0.45-m pore size membrane filter(Note 2)at thetime of sampling.This definition of“dissolved”barium isarbitrary since very fine crystals of barium sulfate may passthrough the membrane filter.NOTE2These filters have been found to be contaminated to variousdegrees with heavy metals depending on the manufacturer.Care should be1This 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 Sept.1,2011.Published September 2011.Originallyapproved in 1981.Last previous edition approved in 2007 as D3986 07.DOI:10.1520/D3986-11.2For 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 exercised in selecting a source for these filters.It has been found to be agood practice to wash the filters with nitric acid and then reagent waterbefore filtering a sample.4.5 If there are no visible suspended solids in the sample,total recoverable barium may be determined on an acidifiedunfiltered sample in the same manner as dissolved barium.4.6 When the sample contains suspended solids total recov-erable barium is determined by an acid digestion step todestro