ASTM D3869-2015 Standard Test Methods for Iodide and Bromide Ions in Brackish Water Seawater and Brines《微咸水 海水及卤水中碘和溴离子的标准试验方法》.pdf

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1、Designation: D3869 15Standard Test Methods forIodide and Bromide Ions in Brackish Water, Seawater, andBrines1This standard is issued under the fixed designation D3869; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las

2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods2cover the determination of solubleiodide and bromide ions, or both, in brackish water, seawater,and b

3、rines. Four test methods are given as follows:1.1.1 Test Method A for both Iodide and Bromide IonsVolumetric, for concentrations from 0.2 to 2000 mg/L iodideand from 5 to 6500 mg/L bromide (Sections 715).1.1.2 Test Method B for Iodide IonColorimetric, for con-centrations from 0.2 to 2000 mg/L iodide

4、 (Sections 1625).1.1.3 Test Method C for Iodide IonSelective electrode, forconcentrations from 1 to 2000 mg/L iodide (Sections 2634).1.1.4 Test Method D for Bromide IonColorimetric, forconcentrations from 40 to 6500 mg/L bromide (Sections 35 44).1.2 Test MethodAis intended for use on all brackish wa

5、ters,seawaters, and brines that contain appreciable amounts ofiodide or bromide ions or both. Test Methods B, C, and D,because of their rapidity and sensitivity, are recommended forthe analysis of brackish waters, seawaters, and brines in thefield and in the laboratory.1.3 Samples containing from 0.

6、2 to 2000 mg/L of iodide or5 to 6500 mg/Lof bromide may be analyzed by these methods.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated

7、 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. For specificprecautionary statements, see 20.2 and 39.2.2. Referenced Documents2.1 ASTM Standards:3D1129

8、Terminology Relating to WaterD1193 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 ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Qu

9、ality Control Specificationsfor Standard Test Methods for Water AnalysisE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by SpectrophotometryE200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical AnalysisE275 Practice for Describing a

10、nd Measuring Performance ofUltraviolet and Visible Spectrophotometers3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D1129.4. Significance and Use4.1 Identification of a brackish water, seawater, or brine isdetermined by comparison of the concent

11、rations of theirdissolved constituents. The results are used to evaluate theorigin of the water, determine if it is a possible pollutant ordetermine if it is a commercial source of a valuable constituentsuch as iodine or bromine.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused i

12、n all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specification of the Committee1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current

13、edition approved March 15, 2015. Published April 2015. Originallyapproved in 1979. Last previous edition approved in 2009 as D3869 09. DOI:10.1520/D3869-15.2Additional information is contained in the following references: Collins,A. G.,Geochemistry of Oilfield Waters, Elsevier, New York, N.Y., 1975,

14、 496 pp.AmericanPetroleum Institute, API Recommended Practice for Analysis of Oilfield Waters,Subcommittee onAnalysis of Oilfield Waters,API RP, 45 2nd ed, 1968, 49 pp.Hoke,S. H, Fletcher, G. E., and Collins, A. G., “Fluoride and Iodide Selective ElectrodesApplied to Oilfield Brine Analysis,” US Dep

15、artment of Energy, Report ofInvestigations, BETC/RI-78/7, 1978.3For 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 websit

16、e.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1on Analytical Reagents of the American Chemical Society,4where such specifications are available. Other grades may beus

17、ed, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Specification D1193, Type I

18、. Other reagent water types maybe used provided it is first ascertained that the water is ofsufficiently high purity to permit its use without adverselyaffecting the precision and bias of the test method. Type IIIwater was specified at the time of round robin testing of thistest method.6. Sampling6.

19、1 Collect the sample in accordance with Practices D3370.TEST METHOD AVOLUMETRIC FOR IODIDEAND BROMIDE7. Scope7.1 This test method is applicable to brackish waters,seawaters, and brines, and is recommended for such waterscontaining appreciable amounts of iodide or bromide, or both.The test method can

20、 be used for concentrations as high as 2000mg/L iodide and 6500 mg/L bromide.8. Summary of Test Method8.1 Iodide in the sample is oxidized with bromine to iodatein a buffered solution, the excess bromine is decomposed withsodium formate, and the iodate reacts with added iodide toform iodine which is

21、 titrated with sodium thiosulfate.8.2 Iodide and bromide are oxidized to iodate and bromate,respectively, with hypochlorite. The excess hypochlorite isdestroyed with sodium formate, leaving iodate and bromate toreact with added iodide to liberate iodine which is titrated withsodium thiosulfate.8.3 T

22、he bromide concentration is calculated by differencebetween the iodide and combined iodide and bromide deter-minations.9. Interferences9.1 Iron, manganese, and organic matter can interfere (Note1).They are removed by precipitation and filtration. Remainingtraces of iron are masked with fluoride.NOTE

23、 1Brines containing surfactants can cause emulsion problems, inwhich case a suitable emulsion breaker can be used.10. Apparatus10.1 Mechanical Bottle Shaker.10.2 Bottles, 200-mL, for use on mechanical shaker.10.3 Pipets.10.4 Hot-Water Bath, thermostatically controlled to 61C.10.5 Erlenmeyer Flasks,

24、250-mL.11. Reagents and Materials11.1 Acetic Acid, glacial.11.2 Ammonium Molybdate SolutionDissolve2gofam-monium molybdate in water and dilute to 100 mL.11.3 Bromine Water (Saturated)Add to 250 mL of waterslightly more liquid bromine (8 to 10 mL) than will dissolve onshaking. Store in a glass-stoppe

25、red amber bottle.11.4 Calcium Carbonate (CaCO3), powdered.11.5 Calcium Oxide (CaO), anhydrous powdered.11.6 Hydrochloric Acid (1+1)Add 1 volume of HCl (spgr 1.19) to 1 volume of water.11.7 Hydrochloric Acid (1+3)Add 1 volume of HCl (spgr 1.19) to 3 volumes of water.11.8 Hydrochloric Acid (1 + 199)Ad

26、d 1 volume of HCl(sp gr 1.19) to 199 volumes of water.11.9 Methyl Red Indicator Solution (0.1 g/L)Dissolve0.01 g of water-soluble methyl red in water and dilute to 100mL.11.10 Potassium Fluoride (KF2H2O)crystalline.11.11 Potassium Iodide (KI), crystals, free of iodates whentested in accordance with

27、American Chemical Society (ACS)specifications.11.12 Sodium Acetate Solution (275 g/L)Dissolve 275 gof sodium acetate trihydrate (NaC2H3O23H2O) in water, todilute to 1 L, and filter.11.13 Sodium Chloride (NaCl), crystals, which, in additionto satisfyingACS specifications, must be free of iodide, ioda

28、te,bromide, and bromate.11.14 Sodium Formate Solution (500 g/L)Dissolve 50 gof sodium formate (NaCHO2) in hot water and dilute to 100mL. This solution must be freshly prepared.11.15 Sodium Hypochlorite SolutionUse a fresh commer-cial sodium hypochlorite or bleach solution containing ap-proximately 5

29、 % NaClO.11.16 Sodium Thiosulfate Solution (0.1 N)Prepare andstandardize as directed in Practice E200.11.17 Sodium Thiosulfate Solution (0.01 N)With a cali-brated pipet transfer 25 mL of the 0.1 N Na2S2O3solution(11.16) into a 250-mLvolumetric flask. Dilute to the mark withwater that has been freshl

30、y boiled and cooled then mix well.This solution shall be prepared not more than 2 days before itis to be used.11.18 Starch Indicator SolutionMake a paste of6gofarrowroot or soluble iodometric starch with cold water. Pourthe paste into 1 L of boiling water. Add 20 g of KOH, mixthoroughly, and allow t

31、o stand for 2 h. Add 6 mL of glacialacetic acid. Mix again and add sufficient HCl (sp gr 1.19) to4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual S

32、tandards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3869 152adjust the pH to 4.0. Store in a glass-stoppered bottle. Starchsolution prepared in this manner will remain che

33、mically stablefor at least 1 year.11.18.1 If a proprietary starch indicator powder is used, itshall be so indicated in reporting the results of the analysis.11.19 Filter PaperPurchase suitable filter paper. The usermust first ascertain that the filter paper is of sufficient purity touse without adve

34、rsely affecting the bias and precision of thetest method.12. Procedure12.1 To remove iron, manganese, and organic matter fromthe sample, add exactly 100 mL of sample to a bottle. Add 1 gof calcium oxide (11.5), stopper, and place the mixture in ashaker for 1 h. Allow the mixture to stand overnight a

35、nd filteron a dry folded filter (11.19), discarding the first 20 mL thatcome through. Brines with specific gravities less than 1.009may be filtered without standing overnight. Prepare a blank inthe same manner.12.2 Transfer an aliquot of the filtrate containing 1 to 2 mgof iodide to a 250-mLErlenmey

36、er flask.Add sufficient water toprovide a total volume of 75 mL.12.3 Add 3 drops of methyl red indicator (11.9). Add HCl(1 + 199) (11.8) dropwise until the mixture is just slightly acid.12.4 Add 10 mLof sodium acetate solution (11.12),1mLofglacial acetic acid (11.1), 4 mL of bromine water (11.3), an

37、dallow to stand for 5 min.12.5 Add 2 mL of sodium formate solution (11.14), blowout any bromine vapor from the neck of the flask, and washdown the sides with water.12.6 When the solution is completely colorless, add 0.2 g ofKF (11.10)and0.5gofKI(11.11). Mix until dissolved and add15 mL of HCl (1 + 1

38、) (11.6).12.7 For final treatment and titration of the sample, proceedas directed in (12.13).12.8 To determine the combined iodide and bromide, trans-fer an aliquot of the filtrate (12.1) containing 1 to 2 mg ofbromide to a 250-mL Erlenmeyer flask.Add sufficient water tomake the total volume 75 mL.1

39、2.9 If necessary add sufficient NaCl (11.13) to produce a3-g chloride content.Add, in order, 10 mLof sodium hypochlo-rite solution (11.15) and approximately 0.4 g of CaCO3(11.4)(or enough so that approximately 0.1 g will remain after thenext step).12.10 Adjust the pH of the solution with HCl (1 + 3)

40、 (11.7)to a pH between 5.5 and 6.0. Heat at 90C for 10 min. (Asmallamount of undissolved CaCO3should remain at this point.)12.11 Remove the flask and cautiously add 10 mL ofsodium formate solution (11.14), return the flask to the waterbath, and keep the contents hot for 5 min more. Observe thetiming

41、 closely. Rinse down the inside of the flask with a fewmillilitres of water and allow the solution to cool to roomtemperature. Do not use a water bath.12.12 Add 3 drops of ammonium molybdate solution (11.2),0.5gofKF(11.10) (if iron is present), 0.5 g of KI (11.11), mixuntil dissolved, and acidify wi

42、th 15 mL of HCl (1 + 1) (11.6).12.13 Titrate the sample (12.7) for iodide or the sample(12.12) for combined iodide and bromide with 0.01 N sodiumthiosulfate solution (11.17) using starch indicator (11.18).Disregard any return of blue color after the endpoint.13. Calculation13.1 Calculate the concent

43、ration of iodide and bromide ionsin milligrams per litre as follows:13.2 Iodide:C 5 E 2 Dwhere:C = corrected millilitres of Na2S2O3solution,E = millilitres of Na2S2O3, sample solution, andD = millilitres of Na2S2O3blank solution.I2, mg/L 5CNS321150where:N = normality of Na2S2O3solution, andS = milli

44、litres of sample.13.3 Bromide:C 5 E 2 DBr2, mg/L 5CNS313320 2 Xwhere:X = concentration of Ias determined above.14. Precision and Bias514.1 The overall precision (ST) and single-operator preci-sion (So) of this test method within their designated ranges varywith the quantity being tested in accordanc

45、e with Table 1 andTable 2.14.2 The bias of the test method determined from recoveriesof known amounts of iodide and bromide in a series ofprepared standards are given in Table 1 and Table 2.NOTE 2The precision and bias estimates are based on the interlabo-ratory study on four artificial brine sample

46、s containing various amounts ofiodide, bromide, and interfering ions as shown in Table 3. Two analysts in5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1061. ContactASTM CustomerService at serviceastm.org.TABLE 1 Determinat

47、ion of Precision and Bias of Iodide Ions,Volumetric MethodsAmount Added,mg/LAmountFound, mg/LSOSTBiasStatisticallySignificant (95 %ConfidenceLevel)12.1 11.4 1 1 5.78 yes116.3 112.5 2 3 3.27 yes771 743 12 15 +2.63 no1375 1282 40 73 6.76 yesD3869 153each of three laboratories performed duplicate deter

48、minations on each of2 days. Practice D2777 was used in developing these precision and biasestimates.14.3 Precision and bias for this test method conforms toPractice D2777 77, which was in place at the time ofcollaborative testing. Under the allowances made in 1.4 ofPractice D2777 13, these precision

49、 and bias data do meetexisting requirements for interlaboratory studies of CommitteeD19 test methods.15. Quality Control15.1 In order to be certain that analytical values obtainedusing these test methods are valid and accurate within theconfidence limits of the test, the following QC procedures mustbe followed when analyzing iodide and bromide.15.2 Calibration and Calibration Verification:15.2.1 Verify the sodium thiosulfate solution (11.17) ac-cording to Practice E200.15.2.2 Verify solution by analyzing a sample at the concen-tration of a