ASTM D5997-1996(2005) Standard Test Method for On-Line Monitoring of Total Carbon Inorganic Carbon in Water by Ultraviolet Persulfate Oxidation and Membrane Conductivity Detection《.pdf

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1、Designation: D 5997 96 (Reapproved 2005)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 D 5997; the number immediately following the desig

2、nation 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 on

3、-line 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 co

4、upled 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 oxida

5、tion. 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

6、 theionic 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 D 4519 for a discussion of the measurement of CO2by

7、conductivity.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 theconduct

8、ivity 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 sam

9、ples 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

10、 the 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.

11、 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:2D 1129 Terminology Relating to WaterD 1192 Guide for Equipment for Sampling W

12、ater andSteam in Closed Conduits3D 1193 Specification for Reagent WaterD 2777 Practice for the Determination of Precision and Biasof Applicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 4519 Test Method for On-Line Determination of Anionsand Carb

13、on Dioxide in 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 D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 inorganic carbon (IC), ncarbon in the form ofca

14、rbon dioxide, carbonate ion, or bicarbonate ion.3.2.2 refractory material, nthat which cannot be oxidizedcompletely under the test method conditions.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.03 on Sampling Water and

15、Water-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of WaterCurrent edition approved June 1, 2005. Published June 2005. Originallyapproved in 1996. Last previous edition approved in 2000 as D 5997 96(2000).2For referenced ASTM standa

16、rds, 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.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh

17、ohocken, PA 19428-2959, United States.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 FundamentalsCarbon can occur in water as inorganicand organic compounds. This test method can be used to makein

18、dependent 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 concentration to obtain meaningful TOCvalues by difference.4.2 The basic steps of this test method are:4.2

19、.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 Oxidation of TC to CO2by action of acid-persulfateaided by ultraviolet (UV) radiation in the TC channel,

20、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 conductivity detector signal to adisplay of carbon concentration in parts per million(ppm = mg/L) or parts

21、 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.FIG. 1 Schematic Diagram of TOC Analyzer SystemD 5997 96 (2005)25. Significance and Use5.1 This test method is useful for detecting and de

22、terminingorganic 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-ceutical, semiconductor, drinking water

23、 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 giving properresponse using the sa

24、mple 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 D 2777 is not applicable. Asspecified in the method, theoretically prepared standards can beus

25、ed to check the calibration of the analyzer. When measuringlevels below 500 g/L, it is difficult to prevent contaminationunless on-line sampling is used. Background water levelsshould be characterized and accounted for to prevent introduc-tion of unacceptable bias. Accuracy of 63 % (15 g/L) or60.5 g

26、/L (#15 g/L) and relative sample standard deviationsof 61 % (15 g/L) or 60.2 g/L (#15 g/L) are typical forTOC depending on the matrix (especially IC level) and samplelevel. Table 2 and Table 3 provide typical performance data at500 and 25 000 g/L C.15.2 Fig. 2 shows instrument response for carbon ve

27、rsuscarbon 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 concentrations against the analyzedconce

28、ntration.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 quantitations (LOQ) of 0.5 g/L. Measure-ment

29、s 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 different days witheach concentratio

30、n 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 measuredinitially and then subtr

31、acted from the response. The number ofrepetitions of each sample analyzed in order to calculate thestandard deviations is given in Table 4.16. Keywords16.1 carbon; conductivity; inorganic carbon; membrane;on-line; total organic carbon5Supporting data have been filed at ASTM International Headquarter

32、s and maybe obtained by requesting Research Report RR: D19-1163.6Taylor, 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 =

33、1.769 %standard deviation = 0.162 %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 waterTABLE 3 Precision and Bias at 25 000 g/L CTOC Response, g/L C25 06325 11625 12625 14125 13125

34、 15325 16625 21725 17725 193average = 25 148error = 0.062 %standard 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 waterD 5997 96 (2005)5ANNEX(Mandatory Informat

35、ion)A1. BIBLIOGRAPHYA1.1 Godec, R.D., Kosenka, P.K., Hutte, R.S., “Methodand Apparatus for the 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.A

36、1.3 Deak-Phillips, A., Rathgraber, K., Hutte, R., “On-Line Application of a New TOC Analyzer in 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 Manufact

37、uring,” UltrapureWater, July/August 1994, pp. 2025.NOTE 1Carbon standards prepared from sucrose in low TOC waterCalibration: 25 000 g/L potassium acid phthalateFIG. 2 Instrument Response Versus Carbon ConcentrationTABLE 4 Detection Limit StudyMeasurementTechniqueNumber ofRepetitions (n)ExpectedValue

38、,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 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 0.037Dir

39、ect 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 carbonateD 5997 96 (2005)6ASTM International takes no position resp

40、ecting 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 s

41、tandard 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 Interna

42、tional 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 bel

43、ow.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 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 5997 96 (2005)7