ASTM D888-2005 Standard Test Methods for Dissolved Oxygen in Water《水中溶解氧的标准试验方法》.pdf

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1、Designation: D 888 05Standard Test Methods forDissolved Oxygen in Water1This standard is issued under the fixed designation D 888; 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 i

2、ndicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the determination of dissolvedoxygen in water. Thr

3、ee test methods are given as follows:Range, mg/L SectionsTest Method ATitrimetric ProcedureHigh Level 1.0 8 to 15Test Method BInstrumental Probe Procedure 0.05 to 20 16 to 25Test Method CLuminescence-based Sensor 0.05 to 20 26 to 291.2 The precision of Test Methods A and B was carried outusing a sat

4、urated sample of reagent water. It is the usersresponsibility to ensure the validity of the test methods forwaters of untested matrices.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 to es

5、tablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For a specificprecautionary statement, see Note 17.2. Referenced Documents2.1 ASTM Standards:2D 1066 Practice for Sampling SteamD 1129 Terminology Relating to WaterD 1193 Specifi

6、cation for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisE 200 Practice f

7、or Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 amperometric systems, nthose instr

8、umental probesthat involve the generation of an electrical current from whichthe final measurement is derived.3.2.2 instrumental probes, ndevices used to penetrate andexamine a system for the purpose of relaying information on itsproperties or composition. The term probe is used in these testmethods

9、 to signify the entire sensor assembly, includingelectrodes, electrolyte, membrane, materials of fabrications,etc.3.2.3 potentiometric systems, nthose instrumental probesin which an electrical potential is generated and from which thefinal measurement is derived.4. Significance and Use4.1 Dissolved

10、oxygen is required for the survival andgrowth of many aquatic organisms, including fish. The con-centration of dissolved oxygen may also be associated withcorrosivity and photosynthetic activity. The absence of oxygenmay permit anaerobic decay of organic matter and the produc-tion of toxic and undes

11、irable esthetic materials in the water.5. Purity of Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Soci-

12、ety.3Other grades may be used if it is first ascertained that thereagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.5.1.1 Reagent grade chemicals, as defined in Practice E 200,shall be used unless otherwise indicated. It is intended that allre

13、agents conform to this standard.5.2 Unless otherwise indicated, reference to water shall beunderstood to mean reagent water conforming to SpecificationD 1193, Type I. Other reagent water types may be usedprovided it is first ascertained that the water is of sufficiently1These test methods are under

14、the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved Aug. 15, 2005. Published August 2005. Originallyapproved in 1946. Last previous edition approved in 2003 as D 888 03.2For referenced ASTM

15、 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.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical So

16、ciety, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,M

17、D.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.high purity to permit its use without adversely affecting thebias and precision of the test method. Type II water was

18、specified at the time of round robin testing of this method.6. Sampling6.1 Collect the samples in accordance with PracticesD 1066 and D 3370.6.2 For higher concentration of dissolved oxygen, collectthe samples in narrow mouth glass-stoppered bottles of300-mL capacity, taking care to prevent entrainm

19、ent or solu-tion of atmospheric oxygen.6.3 With water under pressure, connect a tube of inertmaterial to the inlet and extend the tube outlet to the bottom ofthe sample bottle. Use stainless steel, Type 304 or 316, or glasstubing with short neoprene connections. Do not use coppertubing, long section

20、s of neoprene tubing, or other types ofpolymeric materials. The sample line shall contain a suitablecooling coil if the water being sampled is above roomtemperature, in which case cool the sample 16 to 18C. Whena cooling coil is used, the valve for cooling water adjustmentshall be at the inlet to th

21、e cooling coil, and the overflow shallbe to a point of lower elevation. The valve for adjusting theflow of sample shall be at the outlet from the cooling coil. Thesample flow shall be adjusted to a rate that will fill the samplingvessel or vessels in 40 to 60 s and flow long enough to providea minim

22、um of ten changes of water in the sample vessel. If thesampling line is used intermittently, flush the sample line andcooling coil adequately before using.6.4 Where samples are collected at varying depths from thesurface, a special sample bottle holder or weighted samplerwith a removable air tight c

23、over should be used. This unit maybe designed to collect several 250 or 300 mL samples at thesame time. Inlet tubes extending to the bottom of each bottleand the water after passing through the sample bottle or bottlesdisplaces air from the container. When bubbles stop rising fromthe sampler, the un

24、it is filled. Water temperature is measured inthe excess water in the sampler.6.5 For depths greater than 2 m, use a Kemmerer-typesampler. Bleed the sample from the bottom of the samplerthrough a tube extending to the bottom of a 250 to 300 mLbiological oxygen demand (BOD) bottle. Fill the bottle to

25、overflowing and prevent turbulence and the formation ofbubbles while filling the bottle.7. Preservation of Samples7.1 Do not delay the determination of dissolved oxygen.Samples for Test Method A may be preserved 4 to8hbyadding 0.7 mL of concentrated sulfuric acid (sp gr 1.84) and1.0 mL of sodium azi

26、de solution (20 g/L) to the bottlecontaining the sample in which dissolved oxygen is to bedetermined. Biological activity will be inhibited and thedissolved oxygen retained by storing at the temperature ofcollection or by water sealing (inverting bottle in water) andmaintaining at a temperature of 1

27、0 to 20C. Complete thedetermination as soon as possible, using the appropriateprocedure for determining the concentration of dissolvedoxygen.TEST METHOD ATITRIMETRIC PROCEDUREHIGH LEVEL8. Scope8.1 This test method is applicable to waters containing morethan 1000 g/Lof dissolved oxygen such as stream

28、 and sewagesamples. It is the users responsibility to ensure the validity ofthe test method for waters of untested matrices.8.2 This test method, with the appropriate agent, is usablewith a wide variety of interferences. It is a combination of theWinkler Method, theAlsterberg (Azide) Procedure, the

29、Rideal-Stewart (permanganate) modification, and the Pomeroy-Kirshman-Alsterberg modification.8.3 The precision of the test method was carried out using asaturated sample of reagent water.9. Interferences9.1 Nitrite interferences are eliminated by routine use ofsodium azide. Ferric iron interferes un

30、less 1 mL of potassiumfluoride solution is used, in which case 100 to 200 mg/L can betolerated. Ferrous iron interferes, but that interference iseliminated by the use of potassium permanganate solution.High levels of organic material or dissolved oxygen can beaccommodated by use of the concentrated

31、iodide-azide solu-tion.10. Apparatus10.1 Sample Bottles, 250 or 300 mL capacity with taperedground-glass stoppers. Special bottles with pointed stoppersand flared mouths are available from supply houses, but regulartypes (tall or low form) are satisfactory.10.2 Pipettes, 10-mL capacity, graduated in

32、 0.1-mL divi-sions for adding all reagents except sulfuric acid. Thesepipettes should have elongated tips of approximately 10 mmfor adding reagents well below the surface in the sample bottle.Only the sulfuric acid used in the final step is allowed to rundown the neck of the bottle into the sample.1

33、1. Reagents11.1 Alkaline Iodide Solutions:11.1.1 Alkaline Iodide SolutionDissolve 500 g of sodiumhydroxide or 700 g of potassium hydroxide and 135 g ofsodium iodide or 150 g of potassium iodide (KI) in water anddilute to 1 L. Chemically equivalent potassium and sodiumsalts may be used interchangeabl

34、y. The solution should notgive a color with starch indicator when diluted and acidified.Store the solution in a dark rubber-stoppered bottle. Thissolution may be used if nitrite is known to be absent and mustbe used if adjustments are made for ferrous ion interference.11.1.2 Alkaline Iodide-Sodium A

35、zide Solution IThis solu-tion may be used in all of these submethods except whenadjustment is made for ferrous ion. Dissolve 500 g of sodiumhydroxide or 700 g of potassium hydroxide and 135 g ofsodium iodide or 150 g of potassium iodide in water and diluteto 950 mL. To the cooled solution add 10 g o

36、f sodium azidedissolved in 40 mL of water. Add the NaN3solution slowlywith constant stirring. Chemically equivalent potassium andsodium salts may be used interchangeably. The solution shouldD888052not give a color with starch indicator solution when diluted andacidified. Store the solution in a dark

37、 rubber-stoppered bottle.11.1.3 Alkaline Iodide-Sodium Azide Solution IIThis so-lution is useful when high concentrations of organic matter arefound or when the dissolved oxygen concentration exceeds 15mg/L. Dissolve 400 g of sodium hydroxide in 500 mL offreshly boiled and cooled water. Cool the wat

38、er slightly anddissolve 900 g of sodium iodide. Dissolve 10 g of sodium azidein 40 mL of water. Slowly add, with stirring, the azide solutionto the alkaline iodide solution, bringing the total volume to 1 L.11.2 Manganous Sulfate SolutionDissolve 364 g of man-ganous sulfate in water, filter, and dil

39、ute to 1 L. No more thana trace of iodine should be liberated when the solution is addedto an acidified potassium iodide solution.11.3 Potassium Biiodate Solution (0.025 N)Dissolve0.8125 g of potassium biiodate in water and dilute to 1 L in avolumetric flask.NOTE 1If the bottle technique is used, di

40、ssolve 1.2188 g of biiodatein water and dilute to 1 L to make 0.0375 N.11.4 Phenylarsine Oxide Solution (0.025 N)Dissolve2.6005 g of phenylarsine oxide in 110 mL of NaOH solution(12 g/L). Add 800 mL of water to the solution and bring to apH of 9.0 by adding HCl (1 + 1). This should require about 2mL

41、 of HCl. Continue acidification with HCl (1 + 1) until a pHof 6 to 7 is reached, as indicated by a glass-electrode system.Dilute to 1 L. Add 1 mL of chloroform for preservation.Standardize against potassium biiodate solution.NOTE 2Phenylarsine oxide is more stable than sodium thiosulfate.However, so

42、dium thiosulfate may be used. The analyst should specifywhich titrant is used. For a stock solution (0.1 N), dissolve 24.82 g ofNa2S2O35H2O in boiled and cooled water and dilute to 1 L. Preserve byadding 5 mL of chloroform. For a dilute standard titrating solution (0.005N) transfer 25.00 mL of 0.1 N

43、 Na2S2O3to a 500-mL volumetric flask.Dilute to the mark with water and mix completely. Do not prepare morethan 12 to 15 h before use.NOTE 3If the full bottle technique is used, 3.9007 g must be used tomake 0.0375 N.NOTE 4If sodium thiosulfate is used, prepare and preserve a 0.1 Nsolution as describe

44、d in Note 1. Determine the exact normality by titrationagainst 0.025 N potassium biiodate solution. Dilute the appropriatevolume (nominally 250 mL) of standardized 0.1 N Na2S2O3solution to 1L. One millilitre of 0.025 N thiosulfate solution is equivalent to 0.2 mg ofoxygen. If the full bottle techniq

45、ue is followed, use 37.5 mL of sodiumthiosulfate solution and standardize to 0.0375 N.11.5 Starch SolutionMake a paste of6gofarrowrootstarch or soluble iodometric starch with cold water. Pour thepaste into 1 L of boiling water. Then add 20 g of potassiumhydroxide, mix thoroughly, and allow to stand

46、for 2 h. Add 6mL of glacial acetic acid (99.5 %). Mix thoroughly and thenadd sufficient HCl (sp gr 1.19) to adjust the pH value of thesolution to 4.0. Store in a glass-stoppered bottle. Starchsolution prepared in this manner will remain chemically stablefor one year.NOTE 5Powdered starches such as t

47、hyodene have been found ad-equate. Some commercial laundry starches have also been found to beusable.NOTE 6If the indicator is not prepared as specified or a proprietarystarch indicator preparation is used, the report of analysis shall state thisdeviation.11.6 Sulfuric Acid (sp gr 1.84)Concentrated

48、sulfuric acid.One millilitre neutralizes about 3 mL of the alkaline iodidereagent.NOTE 7Sulfamic acid (3 g) may be substituted.11.7 Potassium Fluoride Solution (400 g/L)Dissolve 40 gof potassium fluoride in water and dilute to 100 mL. Thissolution is used in the procedure for eliminating ferric ioni

49、nterference. Store this solution in a plastic bottle.11.8 Potassium Oxalate Solution (20 g/L)Dissolve 2 g ofpotassium oxalate in 100 mL of water. One millilitre of thissolution will reduce 1.1 mL of the KMnO4solution. Thissolution is used in the procedure for eliminating ferrous ioninterference.11.9 Potassium Permanganate Solution (6.3 g/L)Dissolve6.3 g of potassium permanganate in water and dilute to 1 L.With very high ferrous iron concentrations, solution of KMnO4should be stronger so that 1 mL will satisfy the demand. Thissolution is used in the pr