ASTM_D_4779_-_93.pdf

Designation:D 4779 93Standard Test Method forTotal,Organic,and Inorganic Carbon in High Purity Waterby Ultraviolet(UV)or Persulfate Oxidation,or Both,andInfrared Detection1This standard is issued under the fixed designation D 4779;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 totalcarbon(TC),organic carbon(OC),and inorganic carbon(IC),in makeup water and high purity process water such asdemineralizer effluent,condensate,and electronic grade rinsewater.The tested concentration range is from 50 to 1000 g ofcarbon per litre.1.2 It is the users responsibility to ensure the validity of thistest method for waters of untested matrices.1.3This standard does not purport to address all of thesafety problems,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:D 1129 Terminology Relating to Water2D 1192 Specification for Equipment for Sampling Waterand Steam in Closed Conduits2D 1193 Specification for Reagent Water2D 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D-19 on Water2D 3370 Practices for Sampling Water from Closed Con-duits23.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 inorganic carbon(IC)carbon in the form of carbondioxide,carbonate ion,or bicarbonate ion.3.2.2 organic carbon(OC;frequently also TOC)carbon inthe form of organic compounds.3.2.3 total carbon(TC)the sum of inorganic and organiccarbon.4.Summary of Test Method4.1 For total carbon measurement,sample is injected into agas-sparged reactor containing acidified potassium persulfate(K2S2O8)or sodium persulfate(Na2S2O8)solution;eitherelevated temperature or ultraviolet(UV)radiation is used toenhance the oxidation.Both inorganic and organic carboncompounds are converted into CO2,which is swept,eitherdirectly or by trapping and thermal desorption,to a CO2-specific linearized infrared detector.Output signal is measuredas peak height or integrated area and results displayed asfractional milligrams of carbon per litre or equivalent.Fordirect organic carbon determination,the sample is acidified andsparged to remove inorganic carbon,prior to oxidation(purge-able organic compounds may be lost in this procedure).Forinorganic carbon measurement,the CO2sparged off in theorganic carbon step may be quantified,or the sample may beinjected into the reactor with the UV source off so that organicsare not oxidized.4.2 Organic carbon may also be measured as the differencebetween“total carbon and“inorganic carbon results.5.Significance and Use5.1 Accurate measurement of organic carbon in water at lowand very low levels is of particular interest to the electronic,pharmaceutical,and steam power generation industries.5.2 Elevated levels of organics in raw water tend to degradeion exchange capacity.Elevated levels of organics in highpurity water tend to encourage biological growth and,in somecases,are directly detrimental to the processes that require highpurity water.5.3 In the case of steam power generation,naturally occur-ring organics can degrade to CO2and low molecular weightorganic acids which,in turn,are corrosive to the processequipment.5.4 Inorganic carbon can also cause problems in a steampower system.CO2entering steam condensate that containsammonia,reacts to form ammonium carbonate,which is notremoved by the condenser air ejection system.If condensatepolishers are operated beyond the ammonia break,continuedoperation on an ammonium cycle can result in selectiveexhaustion of the anion resin to the carbonate form,elutingsilica,chloride,and sulfate into the condensate.The effect isimmediately felt with powdered resin systems that have a very1This test method is under the jurisdiction of ASTM Committee D-19 on Waterand is the direct responsibility of Subcommittee D19.11 on Standards for Water forPower Generation and Processes.Current edition approved Sept.15,1993.Published November 1993.Originallypublished as D 4779 88.Last previous edition D 4779 88.2Annual Book of ASTM Standards,Vol 11.01.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMsmall inventory of anion resin.6.Interferences and Limitations6.1 If IC level is much higher than OC,the latter should bedetermined directly by acidifying the sample and sparging offIC before injection.Determination of OC by difference mayintroduce large error in such circumstances.6.2 Th