ASTM D5543-1994(2005) Standard Test Methods for Low-Level Dissolved Oxygen in Water《水中低水平溶解氧的标准试验方法》.pdf

1、Designation: D 5543 94 (Reapproved 2005)Standard Test Methods forLow-Level Dissolved Oxygen in Water1This standard is issued under the fixed designation D 5543; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis

2、ion. 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 These test methods cover the determination of low-level(100 g/L) dissolved oxygen in thermal-cycle steam conden-sate, deaerated

3、 boiler feedwater, boiler water, and deaerateddeionized water. The following test methods are included:Range, g/L SectionsTest Method AColor Comparator TestMethod Using Self-Filling GlassAmpoules0to100 8to17Test Method BInstrument Test MethodUsing Self-Filling Glass Ampoules0 to 100 18 to 261.2 Thes

4、e test methods may be applicable to electronic-grade, pharmaceutical-grade, and other high-purity waters,although these were not addressed in the collaborative study.1.3 Test Method A is a colorimetric procedure applicable todissolved oxygen in water in the range from 0 to 100 g/L.1.4 Test Method B

5、is an instrumented colorimetric proce-dure applicable to dissolved oxygen in water in the range from0 to 100 g/L.1.5 It is the users responsibility to ensure the validity ofthese test methods for waters of untested matrices.1.6 The values stated in SI units are to be regarded as thestandard.1.7 This

6、 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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents

7、2.1 ASTM Standards:2D 1066 Practice for Sampling SteamD 1129 Terminology Relating to WaterD 1192 Specification for Equipment for Sampling Waterand Steam in Closed Conduits3D 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee

8、D19 on WaterD 3370 Practices for Sampling Water from Closed Conduits3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D 1129.4. Significance and Use4.1 Dissolved oxygen is detrimental in certain boiler andsteam cycles because it may accelerate corr

9、osion. Concentra-tions above 10 g/L are unacceptable in many high-pressureboiler systems. The efficiency of dissolved oxygen removalfrom boiler feedwater by chemical or mechanical means, orboth, is determined by measuring the concentration before andafter the process. The measurement is also made to

10、 check forair leakage into the boiler system.4.2 The oxygen treatment method for boiler corrosionreduction requires injection of oxygen into the boiler feedwa-ter. The resulting oxygen level is monitored for controlpurposes.5. Reagents5.1 This test method does not require the preparation of anyreage

11、nts. All the necessary analytical reagents are provided bythe manufacturer in sealed ampoules.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.6. Precautions6.1 Users must exercise caution by usin

12、g finger cots, inaccordance with the manufacturers instructions, when han-dling the mixing of sample and reagent in the glass ampoules.7. Sampling7.1 Sampling is the most critical part of any dissolvedoxygen test. The sample stream must be completely leak-free,1These test methods are under the juris

13、diction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.03 on Sampling ofWater and Water-Formed Deposits, Analysis of Water for Power Generation andProcess Use, On-Line Water Analysis, and Surveillance of Water.Current edition approved Jan. 1, 2005. Published Janu

14、ary 2005.Originally approved in 1994. Last previous edition approved in 1999 asD 5543 94 (1999)e1.2For 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 Docu

15、ment Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.since even the smallest leak can elevate the oxygen level in thesample and cause large errors in the results. New or intermit-tently used

16、 sampling systems must be purged for a minimum of4 h. Sample streams that are used routinely may require only afew minutes of purging.7.2 Collect the samples in accordance with PracticesD 1066 and D 3370 and Specification D 1192.7.3 With water under pressure, connect a tube of inertmaterial to the i

17、nlet and extend the tube outlet to the bottom ofthe sample bottle or tube. Use stainless steel, Type 304 or 316,or glass tubing with short neoprene connections. Do not usecopper tubing, long sections of neoprene tubing, or other typesof elastomeric polymeric materials. If the water being sampledis a

18、bove room temperature, the sample line shall contain asuitable cooling coil to cool it to approximate room tempera-ture.TEST METHOD ACOLOR COMPARATOR TESTMETHOD USING SELF-FILLING GLASS AMPOULES8. Scope8.1 This test method covers the rapid, routine determinationof dissolved oxygen in steam condensat

19、e, deaerated boilerfeedwater, and deaerated deionized water. Color comparatorsallow the estimation of concentrations ranging from 0 to 100g/L (ppb) oxygen.8.2 This test method was tested in steam condensate,deaerated boiler feedwater, and deaerated deionized water. It isthe users responsibility to e

20、nsure the validity of the testmethod for waters of untested matrices.9. Summary of Test Method9.1 The tip of a partially evacuated sealed ampoule isbroken while submerged in a flowing water sample. Thesample is drawn into the ampoule where it reacts instanta-neously with the oxygen-sensitive indicat

21、or to produce areddish violet color whose intensity is proportional to theconcentration of dissolved oxygen.410. Interferences10.1 Color, turbidity, and oxidizing impurities interfere inthis test method to yield high results. If the sample is coloredor turbid or contains oxidizing impurities, the am

22、ount ofinterference that may be contributed by such effects must bedetermined independently prior to using this test method.10.2 Easily reduced metal ions may interfere in this testmethod to cause high results. For example, 100 g/L (ppb) Cu+2 may appear as 5 g/L (ppb) dissolved oxygen, and 100 g/LFe

23、+3may appear as 7 g/L dissolved oxygen. However, lessthan 50 g/L Cu+2or Fe+3cause less than 1-g/L interference.10.3 Hydrogen peroxide alone in concentrations up to 200g/L does not affect the measurement of 1.5 g/L of dissolvedoxygen. Above 200 g/L hydrogen peroxide, there is a positiveinterference o

24、f 3.3 g/L dissolved oxygen per 100 g/L excessover 200 g/L hydrogen peroxide.10.4 The following interferences occur in the presence of2200 mg/L boron present as boric acid: (1) at pH levels belowpH 6, recovery can be as low as 80 %; ( 2) added hydrogenperoxide at a concentration of 0.1 mg/L yields a

25、positiveinterference of 10 g/L dissolved oxygen; and ( 3) addedhydrogen peroxide in a concentration range from 0.5 to 650mg/L yields a positive interference of 20 to 25 g/L.NOTE 1Measurements of 0 to 100 g/L of dissolved oxygen areunaffected by the presence of 2200 mg/L boron present as boric acid a

26、t pH6 and above in the absence of hydrogen peroxide.10.5 Benzoquinone, an oxidation product of hydroquinone,interferes with this test method. One hundred micrograms perlitre of benzoquinone may appear as 33 g/L dissolved oxygen.10.6 Reducing agents such as hydrazine and sulfite do notinterfere at 5-

27、mg/L (ppm) levels in the sample.10.7 Ampoules must be protected from light to preventdarkening. Follow the manufacturers storage recommenda-tions.10.8 Color comparator tubes must be protected from light toprevent fading. Follow the manufacturers storage recommen-dations.11. Apparatus11.1 Color Compa

28、rator, for 0, 2, 4, 6, 8, 12, 16, and 20 g/L(ppb) of oxygen.11.2 Color Comparator, for 0, 5, 10, 15, 20, 25, 30, and 40g/L (ppb) of oxygen.11.3 Color Comparator, for 0, 10, 20, 30, 40, 60, 80, and100 g/L (ppb) of oxygen.11.4 Sampling Tube. See Fig. 1.12. Reagents and Materials12.1 Sealed, evacuated

29、glass ampoules containing oxygen-sensitive indicator.4Spokes, G. N., Dissolved Oxygen in Water Measurement and Standardization,EPRI PWR Plant Chemists Meeting, San Diego, CA, Nov. 1720, 1992. Copiesobtainable from CHEMetrics Inc., Route 28, Calverton, VA 22016.FIG. 1 Sampling Tube for Use with Ampou

30、les to MeasureDissolved Oxygen in a Flowing Water SampleD 5543 94 (2005)213. Sampling13.1 Attach the feedwater source to the plastic samplingtube as described in 7.3. Clamps may be attached to the tube tohold it vertical, or it can be attached to a vertical rod or pipeabove a sink, drain, or bucket.

31、14. Calibration and Standardization14.1 No calibration is required.NOTE 2The color comparator standards are precalibrated by themanufacturer for measurement of dissolved oxygen in water.14.2 A dissolved-oxygen-in-water standard may be gener-ated by following the procedures given in Appendix X1.15. P

32、rocedure15.1 Insert the ampoule into the sampling device, with thepointed end down. Allow the sample to flow at least 5 min.A15-min wait time may be necessary to achieve the bestaccuracy for samples with below 20 g/L of dissolved oxygen.15.2 Gently press the ampoule toward the wall of thesampling tu

33、be to snap off the tip, and remove thc ampoule,keeping the tip down, immediately after filling is complete.15.3 Using a protective rubber finger cot, place a finger overthe broken tip. (Warningglass may be sharp.) Invert theampoule several times to mix the contents, allowing the bubbleto travel from

34、 end to end each time. Wipe all liquid from theexterior of the ampoule.NOTE 3A small bubble of inert gas will remain in the ampoule tofacilitate mixing.NOTE 4Due to the possibility of air leaking in during this step, it isadvisable to run tests in duplicate. It should be noted, however, that somevar

35、iation in observed concentrations may be due to changes in systemconditions.15.4 Use the color comparator as illustrated in Fig. 2 todetermine the level of dissolved oxygen in the sample. Placethe ampoule in the center (empty) tube of the comparator, withthe flat end downward. Direct the top of the

36、comparator towarda source of bright, white light while viewing from the bottom.Hold the comparator in a nearly horizontal position, and rotateit until the color standard below thc ampoule shows the closestmatch. Complete this color matching procedure in less than 30s after snapping the tip in the sa

37、mple.NOTE 5The color intensity may continue to increase after the rapidinitial color reaction. However, it is the initial color reaction that iscomplete within 30 s, and to which the system calibrations apply.15.4.1 Find the analytical result from the concentrationvalue of the closest matching color

38、 standard as designated onthe comparator label. Estimate the concentration to within ahalf color standard interval.16. Calculation16.1 The dissolved oxygen content of the sample is thevalue obtained in 15.4. Use the average of the two resultingvalues if two ampoules are used.17. Precision and Bias51

39、7.1 The overall precision and bias of this test methodcannot be determined by round-robin testing because of theinstability of shipping solutions.17.2 This test method was evaluated for single-operatorprecision by eight laboratories, with a total of 15 operatorsrunning a total of 200 samples in trip

40、licate. The collaborativetest data were obtained on the samples available at thelaboratory site locations. These data may not apply for othermatrices.17.2.1 The single-operator precision, So, of this test methodwas found to be dependent on the ampoule type and to bepartly dependent on the dissolved

41、oxygen content of thesample. The data are summarized in the tables that follow.17.2.1.1 The data in the following table were obtained using0 to 20-g/L (ppb) range ampoules and comparators.6A totalof 66 samples was measured in triplicate by a total of 15operators in 8 laboratories:Range, g/L (ppb) 0

42、to 0.9 1 to 4.9 5 to 9.9 10 to 14.9 15 to 20So0.20 1.6 2.5 1.4 3.217.2.1.2 The data in the following table were obtained using0 to 40-g/L (ppb) range ampoules and comparators.7A total5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report

43、RR: D191153.6CHEMetrics Catalog No. K7511 kits or R7511 ampoule with a C7511comparator The sole source of supply of the apparatus known to the committee atthis time is CHEMetrics, 4295 Catlett Road, Calverton, VA 20138. If you are awareof alternative suppliers, please provide this information to AST

44、M InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee1, which you may attend.7CHEMetrics Catalog No. K7540 kits or R7540 ampoule with C7540 compara-tor. If you are aware of alternative suppliers, please provide this informati

45、on toASTM International Headquarters.FIG. 2 Use of the ComparatorTest Method AD 5543 94 (2005)3of 78 samples was measured in triplicate by a total of 14operators in 7 laboratories:Range, g/L (ppb) 0 to 1.9 2 to 9.9 10 to 19.9 20 to 29.9 30 to 40So0.15 1.4 2.8 2.7 2.217.2.1.3 The data in the followin

46、g table were obtained using0 to 100-ppb range ampoules and comparators.8A total of 56samples was measured in triplicate by a total of 10 operators in6 laboratories.Range, g/L (ppb) 0 to 4.9 5 to 19.9 20 to 39.9 40 to 59.9 60 to 100So0.95 1.1 1.4 5.3 2.917.3 Eight independent laboratories (and a tota

47、l of fifteenoperators) participated in this study. Precision testing for thistest method conforms to Practice D 2777.TEST METHOD BINSTRUMENT TEST METHODUSING SELF-FILLING GLASS AMPOULES18. Scope18.1 This test method covers the rapid routine determinationof dissolved oxygen in steam condensate, deaer

48、ated boilerfeedwater, and deaerated deionized water. This instrumentaltest method provides a digital presentation of dissolved oxygenconcentrations ranging from 0 to 100 g/L (ppb).18.2 This test method was tested on steam condensate,deaerated boiler feedwater, and deaerated deionized water. It isthe

49、 users responsibility to ensure the validity of the testmethod for waters of untested matrices.19. Summary of Test Method19.1 The tip of a partially evacuated sealed ampoule isbroken while submerged in a flowing water sample. Thesample is drawn into the ampoule where it reacts instanta-neously with oxygen-sensitive indicator to produce a reddishviolet color whose intensity is proportional to the concentrationof dissolved oxygen.19.2 The ampoule is then placed in a bichromatic,microprocessor-controlled spectrophotometer instrumen