ASTM D5997-1996(2009) 3750 Standard Test Method for On-Line Monitoring of Total Carbon Inorganic Carbon in Water by Ultraviolet Persulfate Oxidation and Membrane Conductivity Detec.pdf

1、Designation: D5997 96 (Reapproved 2009)Standard Test Method forOn-Line Monitoring of Total Carbon, Inorganic Carbon inWater by Ultraviolet, Persulfate Oxidation, and MembraneConductivity Detection1This standard is issued under the fixed designation D5997; the number immediately following the designa

2、tion 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. Scope1.1 This test method covers the on-li

3、ne determination oftotal carbon (TC), inorganic carbon (IC), and total organiccarbon (TOC) in water in the range from 0.5 g/L to 50 000g/L of carbon. Higher carbon levels may be determined bysuitable on-line dilution. This test method utilizes ultraviolet-persulfate oxidation of organic carbon coupl

4、ed with a CO2selective membrane to recover the CO2into deionized water.The change in conductivity of the deionized water is measuredand related to carbon concentration in the oxidized sampleusing calibration data. Inorganic carbon is determined in asimilar manner without the requirement for oxidatio

5、n. In bothcases, the sample is acidified to facilitate CO2recovery throughthe membrane. The relationship between the conductivitymeasurement and carbon concentration can be described by aset of chemometric equations for the chemical equilibrium ofCO2, HCO3,H+, and OH, and the relationship between th

6、eionic concentrations and the conductivity. The chemometricmodel includes the temperature dependence of the equilibriumconstants and the specific conductances resulting in linearresponse of the method over the stated range of TOC. See TestMethod D4519 for a discussion of the measurement of CO2bycond

7、uctivity.1.2 This test method has the advantage of a very highsensitivity detector that allows very low detection levels onrelatively small volumes of sample. Also, the use of twomeasurement channels allows determination of IC in thesample independently of organic carbon. Isolation of theconductivit

8、y detector from the sample by the CO2selectivemembrane results in a very stable calibration with minimalinterferences.1.3 This test method was used successfully with reagentwater spiked with sodium carbonate and various organiccompounds. This test method is effective with both deionizedwater samples

9、 and samples of high ionic strength. It is theusers responsibility to ensure the validity of this test methodfor waters of untested matrices.1.4 This test method is applicable only to carbonaceousmatter in the sample that can be introduced into the reactionzone. The inlet system generally limits the

10、 maximum size ofparticles that can be introduced. Filtration may also be used toremove particles, however, this may result in removal oforganic carbon if the particles contain organic carbon.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It

11、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 WaterD1192 Guide for Equipment for Sampling Water a

12、nd Steamin Closed Conduits3D1193 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 ConduitsD4519 Test Method for On-Line Determination of Anionsand Carbon Dioxide in

13、High Purity Water by CationExchange and Degassed Cation Conductivity3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 inorganic carbon (IC), ncarbon in the form ofcarbon dioxide, c

14、arbonate ion, or bicarbonate ion.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillan

15、ce of Water.Current edition approved Oct. 1, 2009. Published November 2009. Originallyapproved in 1996. Last previous edition approved in 2000 as D5997 96 (2005).DOI: 10.1520/D5997-96R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servicea

16、stm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh

17、ocken, PA 19428-2959, United States.3.2.2 refractory material, nthat which cannot be oxidizedcompletely under the test method conditions.3.2.3 total carbon (TC), nthe sum of IC and TOC.3.2.4 total organic carbon (TOC), ncarbon in the form oforganic compounds.4. Summary of Test Method4.1 Fundamentals

18、Carbon can occur in water as inorganicand organic compounds. This test method can be used to makeindependent measurements of IC and TC and can also deter-mine TOC as the difference between TC and IC. If IC is highrelative to TOC, it is desirable to use a vacuum degassing unitto reduce the IC concent

19、ration to obtain meaningful TOCvalues by difference.4.2 The basic steps of this test method are:4.2.1 Conversion of remaining IC to CO2by action of acid,4.2.2 Removal of IC, if desired, by vacuum degassing,4.2.3 Split of flow into two streams to provide for separateIC and TC measurements,4.2.4 Oxida

20、tion of TC to CO2by action of acid-persulfateaided by ultraviolet (UV) radiation in the TC channel,4.2.5 Detection of CO2by passing each liquid stream overmembranes that allow the specific passage of CO2to high-purity water where change in conductivity is measured, and4.2.6 Conversion of the conduct

21、ivity detector signal to adisplay of carbon concentration in parts per million(ppm = mg/L) or parts per billion (ppb = g/L). The IC channelreading is subtracted from the TC channel reading to give aTOC reading. A diagram of suitable apparatus is given in Fig.1.5. Significance and Use5.1 This test me

22、thod is useful for detecting and determiningorganic and inorganic carbon impurities in water from a varietyof sources including industrial water, drinking water, and wastewater.5.2 Measurement of these impurities is of vital importanceto the operation of various industries such as power, pharma-ceut

23、ical, semiconductor, drinking water treatment, and wastetreatment. Semiconductor and power applications require mea-surement of very low organic carbon levels (TOC 18 Mohm-cm. If either the TC orIC channel measures 10 g/L, the resin may need replace-ment.14.4 The user should confirm that the unit is

24、 giving properresponse using the sample matrix with compound types ofinterest and operating under the environmental extremes ofinterest.15. Precision and Bias515.1 Since this test method involves continuous samplingand measurement, Practice D2777 is not applicable. As speci-fied in the method, theor

25、etically prepared standards can be usedto check the calibration of the analyzer. When measuring levelsbelow 500 g/L, it is difficult to prevent contamination unlesson-line sampling is used. Background water levels should becharacterized and accounted for to prevent introduction ofunacceptable bias.A

26、ccuracy of 63 % (15 g/L) or 60.5 g/L(#15 g/L) and relative sample standard deviations of 61%(15 g/L) or 60.2 g/L (#15 g/L) are typical for TOCdepending on the matrix (especially IC level) and sample level.Table 2 and Table 3 provide typical performance data at 500and 25 000 g/L C.15.2 Fig. 2 shows i

27、nstrument response for carbon versuscarbon concentration over five orders of magnitude from 0.25 g/L C to 25 000 g/L C for two instruments calibrated at25 000 g/L C. The limit of detection (LOD) for this testmethod was estimated by plotting the standard deviation foreach of the three lowest concentr

28、ations against the analyzedconcentration.6From this data the y-intercept is considered tobe the best estimate of the precision at zero concentration (S0).The S0value was determined to be 0.020 g/L. The LOD isassigned as three times S0or 0.060 g/L. This data supports theassigned limit of quantitation

29、s (LOQ) of 0.5 g/L. Measure-ments of TOC were determined by introducing a knownamount of standard directly into a continuous water sampleusing a metering pump or by preparing and analyzing flaskscontaining standards prepared using volumetric additions (seeTable 4). The data was taken on several diff

30、erent days witheach concentration level determined on a single day. Forcontinuous flow data, the baseline level of TOC was measuredbefore and after the standard addition, and the average baselineTOC values were subtracted from the measured TOC values.For analyses taken from flasks, the baseline was

31、measuredinitially and then subtracted from the response. The number ofrepetitions of each sample analyzed in order to calculate thestandard deviations is given in Table 4.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report D19-1163.6Ta

32、ylor, J. K., “QualityAssurance of Chemical Measurements,” Louis Publisher,Chelsea, MI, 1987, pp. 7882.TABLE 2 Precision and Bias at 500 g/L CTOC Response, g/L C489.7489.8490.5490.2491.5490.1490.6490.8491.8491.9average = 490.7error = 1.769 %standard deviation = 0.162 %NOTE 1 Sample: 499.5 g/L C as su

33、crose in DI waterCalibration: 25.0 3 103g/L C as potassium acid phthalate25.0 3 103g/L C as sodium carbonateZero: Low TOC (5 g/L C) DI waterTABLE 3 Precision and Bias at 25 000 g/L CTOC Response, g/L C25 06325 11625 12625 14125 13125 15325 16625 21725 17725 193average = 25 148error = 0.062 %standard

34、 deviation = 0.172 %NOTE 1 Sample: 499.5 g/L C as sucrose in DI waterCalibration: 25.0 3 103g/L C as potassium acid phthalate25.0 3 103g/L C as sodium carbonateZero: Low TOC (5 g/L C) DI waterD5997 96 (2009)516. Keywords16.1 carbon; conductivity; inorganic carbon; membrane;on-line; total organic car

35、bonNOTE 1Carbon standards prepared from sucrose in low TOC waterCalibration: 25 000 g/L potassium acid phthalateFIG. 2 Instrument Response Versus Carbon ConcentrationD5997 96 (2009)6ANNEX(Mandatory Information)A1. BIBLIOGRAPHYA1.1 Godec, R.D., Kosenka, P.K., Hutte, R.S., “Methodand Apparatus for the

36、 Determination of Dissolved Carbon inWater,” U.S. Patent No. 5,132,094 (July 21, 1992).A1.2 Godec, R., ONeill, K., Hutte, R., “New Technologyfor TOC Analysis in Water,” Ultrapure Water, Dec. 1992, pp.1722.A1.3 Deak-Phillips, A., Rathgraber, K., Hutte, R., “On-Line Application of a New TOC Analyzer i

37、n the PowerIndustry,” Proceedings of the 1993 Chemistry On-Line ProcessInstrumentation Seminar, Clearwater, FL.A1.4 Barley, R., Hutte, R., ONeill, K., “Application ofTOC Monitoring in Semiconductor Manufacturing,” UltrapureWater, July/August 1994, pp. 2025.ASTM International takes no position respec

38、ting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This sta

39、ndard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internati

40、onal Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below

41、.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (f

42、ax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 4 Detection Limit StudyMeasurementTechniqueNumber ofRepetitions (n)ExpectedValue,g/LMeanMeasuredResponse,g/LStandardDeviation,g/LGrab from flask 10 25 159 25 143 43.3Grab from flask 10 495.9 487.1 0.793Grab from flask

43、10 50.00 50.89 0.279Direct on-line 8 15.68 15.70 0.084Direct on-line 9 6.359 6.996 0.091Grab from flask 10 4.990 5.463 0.102Direct on-line 10 0.519 0.488 0.037Direct on-line 9 0.227 0.223 0.014NOTE 1 Sample: Sucrose in waterSample introduced by metering pump into continuous stream or asstandard addition to flaskCalibration: 25.0 3 103g/L C as potassium acid phthalate25.0 3 103g/L C as sodium carbonateD5997 96 (2009)7