1、Designation: D5173 15Standard Guide forOn-Line Monitoring of Total Organic Carbon in Water byOxidation and Detection of Resulting Carbon Dioxide1This standard is issued under the fixed designation D5173; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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. Scope1.1 This guide covers the selection, establishment, andapplication of monitoring systems
3、for carbon and carboncompounds by on-line, automatic analysis, and recording orotherwise signaling of output data. The system chosen willdepend on the purpose for which it is intended (for example,regulatory compliance, process monitoring, or to alert the userto adverse trends) and on the type of wa
4、ter to be monitored(low purity or high purity, with or without suspendedparticulates, purgeable organics, or inorganic carbon). If it is tobe used for regulatory compliance, the test method publishedor referenced in the regulations should be used in conjunctionwith this guide and other ASTM test met
5、hods. This guidecovers carbon concentrations of 0.05 g/L to 50 000 mg/L.Low end sensitivity and quantitative results may vary amonginstruments. This guide covers the on-line measurement tech-niques listed in Table 1. Additional laboratory test methods areavailable: Test Methods D4129, D4839, D5904,
6、D6317, andD7573.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 t
7、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice
8、 for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD3864 Guide for On-Line Monitoring Systems for WaterAnaly
9、sisD4129 Test Method for Total and Organic Carbon in Waterby High Temperature Oxidation and by CoulometricDetectionD4453 Practice for Handling of High Purity Water SamplesD4839 Test Method for Total Carbon and Organic Carbon inWater by Ultraviolet, or Persulfate Oxidation, or Both, andInfrared Detec
10、tionD5904 Test Method for Total Carbon, Inorganic Carbon, andOrganic Carbon in Water by Ultraviolet, PersulfateOxidation, and Membrane Conductivity DetectionD5997 Test Method for On-Line Monitoring of TotalCarbon, Inorganic Carbon in Water by Ultraviolet, Persul-fate Oxidation, and Membrane Conducti
11、vity DetectionD6317 Test Method for Low Level Determination of TotalCarbon, Inorganic Carbon and Organic Carbon in Waterby Ultraviolet, Persulfate Oxidation, and Membrane Con-ductivity DetectionD7573 Test Method for Total Carbon and Organic Carbon inWater by High Temperature Catalytic Combustion and
12、Infrared Detection2.2 Other Standards:EN1484 European Standard Water Analysis Guidelines forthe Determination of Total Organic Carbon (TOC) andDissolved Organic Carbon (DOC)33. Terminology3.1 Definitions:3.1.1 For definitions of other terms used in this guide, referto Terminology D1129 and Guide D38
13、64.3.2 Definitions of Terms Specific to This Standard:3.2.1 electrical conductivity, nthe reciprocal of the acresistance in ohms measured between opposite faces of a1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.03 on Sampling
14、 Water and Water-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved Feb. 15, 2015. Published March 2015. Originallyapproved in 1991. Last previous edition approved in 2007 as D5173 97 (2007).DOI: 10.1520/
15、D5173-15.2For 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.3Available from European Committee for Standardizati
16、on (CEN), AvenueMarnix 17, B-1000, Brussels, Belgium, http:/www.cen.eu.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1centimetre cube of an aqueous solution at a specifiedtemperature, measured in units of siemens/cm.4. Summary of Gui
17、de4.1 A representative sample of a water stream, or the waterstream itself flows into a reaction chamber where all or someof the dissolved organic carbon is oxidized to carbon dioxideby either of two means: (1) a chemical oxidant, an energysource such as ultraviolet (UV) radiation, or both, or (2) h
18、ightemperature combustion. Some regulatory agencies requirecomplete oxidation. This carbon dioxide is subsequently mea-sured in the gas phase by a non-dispersive infrared detector, oris measured in solution by means of conductivity or membraneconductivity detection.4.2 If there are suspended solids
19、in the water stream, withsome analyzers it is advisable to filter the solids out to preventaccumulation and possible blockage.4.3 If there is inorganic carbon present in the water (in theform of carbonate, bicarbonate, or carbon dioxide), it will alsobe detected as carbon dioxide. If inorganic carbo
20、n is notremoved or compensated before analysis, the monitor willreport total carbon.4.4 Inorganic carbon can be removed from the water streamby acidifying and sparging the sample. This process may alsoremove purgeable organic compounds.4.5 Suspended elemental carbon may not be oxidized bylow-tempera
21、ture methods depending on several factors includ-ing analysis time, particle size and concentration, instrumentdesign, etc.5. Significance and Use5.1 Accurate measurement of organic carbon in water at lowand very low levels is of particular interest to the electronic,life sciences, and steam power g
22、eneration industries.5.2 Elevated levels of organics in raw water tend to degradeion exchange resin capacity. Elevated levels of organics in highpurity water tend to support biological growth and, in somecases, are directly detrimental to the processes that require highpurity water.5.3 In power gene
23、ration, naturally occurring organics canbecome degraded to CO2and low molecular weight organicacids that, in turn, are corrosive to the process equipment. Theireffect on conductivity may also cause water chemistry operat-ing parameters to be exceeded, calling for plant shutdown.Halogenated and sulfo
24、nated organics may not be detectable byconductivity but at boiler temperatures will release highlycorrosive chlorides, sulfates, etc.5.4 In process water in other industries, organic carbon cansignify in-leakage of substances through damaged piping andcomponents, or an unacceptable level of product
25、loss.5.5 In wastewater treatment, organic carbon measurementof influent and process water can help optimize treatmentschemes. Measurement of organic carbon at discharge maycontribute to regulatory compliance.5.6 In life sciences, control of organic carbon is necessary todemonstrate compliance with r
26、egulatory limits for some typesof waters.6. Interferences6.1 If inorganic carbon (dissolved CO2and ions in equilib-rium with it) is present, it may lead to over-reporting of anorganic carbon measurement unless it is compensated. Ion-exchange resins used for high purity water production typicallyremo
27、ve CO2from the water, so this interferent is absent fromsuch water unless the water stream comes in contact with theatmosphere prior to analysis. However, the ion-exchange resincan break down over time, producing a higher TOC carbonbackground, and must be monitored.6.2 If electrical conductivity is
28、used for the measurement ofCO2, other conductive species in solution may cause over-reporting unless their background conductivity is measured anddeducted or compensated. Background conductivity 2 S/cmor pH 7 or both can cause loss of sensitivity to TOC. Observeinstrument manufacturer specifications
29、. A power plant samplewith elevated pH and conductivity may be conditioned to bewithin acceptable pH and conductivity ranges by continuouslypassing the sample through a cation exchange cartridge. Theresulting TOC measurement will not include organic cationssuch as amines.TABLE 1 TOC Measurement Tech
30、niques and Typical RangesTOC Measurement Technique Typical RangeAFigure ASTM MethodUV Light Oxidation/Conductivity Detection 0.1 g/L to 2 mg/L Fig. 1 .Combustion Oxidation/IR Detection 4 g/L to 20 000 mg/L Fig. 2 .UV Light Oxidation/Conductivity DetectionContinuous Flow 0.1 g/L to 2 mg/L Fig. 3 .UV-
31、Persulfate Oxidation/IR DetectionContinuous Flow 0.5 g/L to 3 000 mg/L Fig. 4 .Catalyzed Ozone Hydroxyl Radical Oxidation/IR Detection 6 g/L to 40 000mg/L Fig. 5 .Heated Persulfate Oxidation/IR Detection 0.05 mg/L to 250 mg/L Fig. 6 .UV Persulfate Oxidation/Membrane Conductivity Detection 0.5 g/L to
32、 50 mg/L Fig. 7 D5997Supercritical Oxidation/IR Detection 0.5 mg/L to 50 000 mg/L Fig. 8 .AConsult manufacturer for specific range of measurement.D5173 1526.3 With electrical conductivity detection systems,halogen-, sulfur-, nitrogen- and phosphorus-containing organiccompounds can result in interfer
33、ence with the TOC measure-ment. If problems are anticipated, the method of detection mustbe modified or the water itself must be treated to reduce theinterfering background sufficiently to meet accuracy require-ments.6.4 If particulates are suspended in the water stream, theymay cause blockage in so
34、me analyzers over a period of time,and may also be hard to oxidize. If problems are anticipated,the water stream should be appropriately filtered upstream ofthe monitor and it must be recognized that results will notinclude solid organics. If the filter used is rated to 0.45 m thenthe parameter meas
35、ured will be dissolved organic carbon(DOC) as defined by EN1484.6.5 Non-dispersive infrared detectors tuned to CO2absor-bance are sensitive to water vapor, which may therefore give apositive interference unless the water vapor is removed.6.6 The membrane conductivity detection technique mayexperienc
36、e positive interference in the presence of low mo-lecular weight, reduced, inorganic acid species such as H2SorHNO2. Such interferences can be eliminated by oxidation orremoval.7. Apparatus7.1 Figs. 1-8 show in block diagram form several designs ofon-line total organic carbon (TOC) analyzers.8. Reag
37、ents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, all reagents shouldconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society.4Other gradesmay be used, provided it is first ascertained t
38、hat the reagent isof sufficient purity to permit its use without decreasing theaccuracy of the determinations.8.2 Purity of Water:8.2.1 Unless otherwise stated, references to water shall beunderstood to mean water meeting the quantitative require-ments of Specification D1193, Type II. The carbon con
39、tent ofthis water should be measured regularly by a suitably sensitivetest method.8.2.2 Water as free as possible of organics relative to thecarbon levels being measured is required when establishing thetest method blank.8.3 Amber glass, HDPE, and TFE fluorocarbon bottlesshould be used to store wate
40、r, organic-free water, and standardsolutions. The bottles should be dedicated to their respectivetypes of solution and should not interfere with the chosenmeasurement technique. Practices D3370, D3694, and D4453address handling of water samples.8.3.1 Clean bottles according to Practice D4453.8.3.2 F
41、ollow the cleaning procedure before each re-use ofthe bottles.8.4 Gas SupplyUse a gas free of CO2and organic matter,of purity specified by the equipment manufacturer.8.5 Organic Carbon Solution, Standard:8.5.1 Prepare high-concentration calibration standards (forexample, 2000 mg/L carbon) using a wa
42、ter-soluble, stablecompound. This stock solution can then be further diluted to aconcentration suitable for the method used.8.5.2 The compound used for calibration should be assimilar as possible to the compound(s) expected to be presentin the water to be analyzed.8.5.3 Commercial standards are avai
43、lable from severalsources in place of self-made standards. Verify that standardsare certified and within their shelf life before using.9. Hazards9.1 Give full consideration to safe disposal of the analyzersspent samples and reagents and cleaning solutions.9.2 Provide pressure relief valves, if appli
44、cable, to protectboth the analyzer and monitoring system.9.3 Take precautions when using cylinders containing gasesor liquids under pressure:9.3.1 Gas cylinders must be handled by trained personnelonly.9.3.2 Fasten gas cylinders to a rigid structure.9.3.3 Take special safety precautions when using o
45、r storingcombustible or toxic gases to ensure that the system is safe andfree of leaks.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards f
46、or LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.NOTE 1The unit employs available water system pressure to rinse theline and test chamber, followed by a downstream valve closure t
47、hatisolates the sample. Subsequent irradiation with intense UV light breaksdown organic compounds in the water, with the liberated carbon formingcarbon dioxide in solution as carbonic acid. By monitoring the change insample conductivity, corrected for temperature, the TOC concentration iscalculated
48、and displayed.FIG. 1 UV Light Oxidation with Conductivity DetectionD5173 15310. Technical Considerations10.1 Carefully define the measurement objective for themonitoring system before specifying the apparatus. Considersuch factors as the expected total level of carbon; whethersignificant inorganic c
49、arbon is likely to be present; whetherthere are significant levels of purgeable organic compounds inthe stream; whether there are particulates in the water; how fastthe system must respond to a change in carbon concentration inthe stream; how accurate the result must be to meet internal andexternal requirements; and how readily the monitors calibra-tion and performance can be checked.10.2 If the monitoring system is intended primarily todetermine compliance with regulatory standards, the accuracy,precision, frequency of sampling, and response time may bedictated
