ASTM_D_6303_-_98.pdf

Designation:D 6303 98An American National StandardStandard Test Method forFormaldehyde in Water1This standard is issued under the fixed designation D 6303;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the form-aldehyde monomer concentration in water and wastewater.1.2 This test method is suitable for free formaldehydeconcentrations in the range of 0.2 to 7.0 mg/L.For samplescontaining concentrations greater than 7 mg/L,dilute withreagent water prior to analysis.Samples containing between0.02 and 0.5 mg/L may be run using a 10-cm cell.1.3 This test method is for use with reagent water andwastewater.It is the users responsibility to ensure the validityof this test method for waters of untested matrices.1.4 Formaldehyde polymers react partially or slowly,orboth,making this test method unsuitable for analysis of thesecompounds.1.5 For specific hazards statements,see Section 9.Thisstandard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water2D 1192 Specification for Equipment for Sampling Waterand Steam in Closed Conduits2D 1193 Specification for Reagent Water2D 1293 Test Methods for pH of Water2D 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D-19 on Water2D 3370 Practices for Sampling Water from Closed Con-duits2D 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of Water2D 4210 Practice for Interlaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data2D 4453 Practice for Handling of Ultra-Pure Water Samples2E 60 Practice for Photometric and SpectrophotometricMethods for Chemical Analysis of Metals3E 200 Practice for Preparation,Standardization,and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis4E 275 Practice for Describing and Measuring Performanceof Ultraviolet,Visible,and Near-Infrared Spectrophotom-eters53.Terminology3.1 Definitions For definitions of terms used in this testmethod,refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 formaldehyde,na monomeric formaldehyde that isunbound.3.2.1.1 DiscussionThis may include dimers,polymers,and formaldehyde resins,which are easily broken down.Itgenerally does not include the firmly bound formaldehydes thatare integral to complex structures,such as wood resins,etc.Since bound formaldehyde is not necessarily quantitativelyreleased and judgement is needed to determine the necessityand extent of releasing it,bound formaldehyde is considered tobe outside the scope of this test method.4.Summary of Test Method4.1 An aliquot of the sample containing 0.2 to 7 mg/L offormaldehyde is combined with an equal volume of theacetylacetone reagent in a test tube.The tube is capped,shaken,and reacted at 60C for 10 min.After cooling,the absorbanceof the solution is read at 412 nm.Colored or turbid samples areextracted with n-butanol prior to reading the absorbance,andthe reading then is taken on the n-butanol extract.Concentra-tion is calculated from a curve of standard formaldehydesolutions.4.2 The chemical reaction is based on the Hantzsch reac-tion.6Formaldehyde reacts with acetylacetone in the presenceof ammonium ion to form the yellow compound,3,5-diacetyl-1,4-dihydro-lutidine.1This test method is under the jurisdiction of ASTM Committee D-19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved July 10,1998.Published March 1999.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 03.05.4Annual Book of ASTM Standards,Vol 15.05.5Annual Book of ASTM Standards,Vol 03.06.6Nash,T.,“The Calorimetric Estimation of Formaldehyde by Means of theHantzch Reaction,”Biochemistry,55,1953,p.416.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.Significance and Use5.1 This test method is used to determine the concentrationof formaldehyde monomer present in water,avoiding many ofthe problems associated with other methods.The equipmentrequired is fairly simple,so the test can be performed underfield conditions.Because of the near-neutral pH of the re-agents,the mild reaction conditions result in very little degra-dation or formation of free formaldehyde.The reagents are notaffected by nitrates or reducing agents.6.Interferences6.1 Color or turbidity after the reaction may interfere i