ASTM_D_3082_-_15.pdf

Designation:D308215Standard Test Method forBoron in Water1This standard is issued under the fixed designation D3082;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 boron inwater and wastewaters by the curcumin colorimetric-extractionmethod2in concentrations between 0.1 and 1.0 mg/L.Therange can be extended by dilution of the sample.1.2 Only dissolved boron is determined.This test methodrequires that the water sample be filtered through a 0.45-mmembrane filter before analysis.1.3 This test method is a colorimetric method that is verysensitive to low concentrations of boron in water and requiresa relatively small sample volume for analysis.1.4 Precision and bias were obtained on natural and waste-waters.It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.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:3D1066 Practice for Sampling SteamD1129 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 ConduitsD4841 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 AnalysisE60 Practice for Analysis of Metals,Ores,and RelatedMaterials by SpectrophotometryE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminology D1129.4.Summary of Test Method4.1 When a water sample containing soluble boron isacidified with hydrochloric acid and evaporated to dryness inthe presence of curcumin,a red-colored complex called roso-cyanine is formed.This colored product is taken up inisopropyl alcohol and is read spectrophotometrically.5.Significance and Use5.1 Because boron can be both essential and deleterious toplant growth,and because ingestion of large amounts can affectthe central nervous system in humans,a method is required todetermine its concentration in potable,natural,and wastewa-ters.This test method provides a means of determining theboron concentration of these waters.The holding time for thesamples may be calculated in accordance with Practice D4841.5.2 Boric acid is used for chemical shim control of neutronflux in a nuclear reactor.This test method serves to determineif the boron concentration is within acceptable limits.6.Interferences6.1 Nitrate concentrations above 20 mg/L begin to interfere.Hardness levels about 100 mg/L as CaCO3give high resultsbecause of the turbidity caused by the insolubility of thehardness salts in isopropyl alcohol.The turbidity can beeliminated by filtering the final solution through a 0.45-mmembrane filter before reading on the spectrophotometer.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 March 2015.Originallyapproved in 1972.Last previous edition approved in 2009 as D3082 09.DOI:10.1520/D3082-15.2This test method is similar to,but not identical with that appearing in StandardMethods for Examination of Water and Wastewater,13th Ed.,American PublicHealth Association,Washington,DC,pp 6972.3For 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 6.2 Organic color may be present in the sample that couldaffect absorbance readings on the spectrophotometer.If aninterfering organic color is present in the sample,the followingprocedure has been found useful in reducing this interferencefor some matrices.Pipet an appropriate sample aliquot into aplatinum dish(Note 1).Make alkaline