ASTM D1246-2010 Standard Test Method for Bromide Ion in Water《水中的溴化物离子的标准试验方法》.pdf

1、Designation: D1246 10Standard Test Method forBromide Ion in Water1This standard is issued under the fixed designation D1246; 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 indicat

2、es the year of last reapproval. Asuperscript epsilon () 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 This test method is applicable to the measurement ofbromide ion in water, ground w

3、ater, and drinking water.1.2 Samples containing 0.5 mg/L to 1000 mg/L of bromidemay be analyzed by this test method. The concentration rangemay be extended by the dilution of an appropriate aliquot.1.3 The precision and bias statements were determined onnatural and ground waters. It is the responsib

4、ility of the analystto assure the validity of this test method for untested matrices.1.4 A titrimetric and two colorimetric test methods foriodide and bromide were discontinued. Refer to Appendix X1for historical information.1.5 The values stated in SI units are to be regarded asstandard. No other u

5、nits of measurement are included in thisstandard.1.6 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 establish appro-priate safety and health practices and determine the applica-bility of re

6、gulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practi

7、ces for Sampling Water from Closed ConduitsD4127 Terminology Used with Ion-Selective ElectrodesD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Terminology3.1 DefinitionsFor definitions of terms used i

8、n this testmethod, refer to Terminologies D1129 and D4127.4. Summary of Test Method4.1 Bromide ion is measured potentiometrically using abromide ion-selective electrode in conjunction with a single-junction, sleeve-type reference electrode. Potentials are read ona pH meter having an expanded millivo

9、lt scale capable of beingread to the nearest 0.1 mV, or a selective ion meter having adirect concentration scale for bromide. For less precise work, apH meter having a millivolt scale capable of being read to thenearest 1.0 mV is adequate, however, no supporting data areavailable.4.2 The electrodes

10、are calibrated in known bromide solu-tions and the concentrations of unknowns are determined insolutions with the same background. In most cases, addition ofan ionic strength adjustor to both standards and samples issufficient to maintain constant background ionic strength. Forsamples above 0.1 M in

11、 ionic strength, prepare standardsolutions similar to the sample composition.5. Significance and Use5.1 By analysis for bromide in water, wastewater, andbrackish waters, it is possible to evaluate the origin of thewater, its potential as a source of bromide, and its conditionwith regard to pollution

12、.6. Interferences6.1 Strongly reducing solutions and solutions containingions which form insoluble silver salts may coat the electrodemembrane. These may be removed by polishing the membranesurface. Sulfide ion and cyanide ion both poison the electrode,and should be removed (see Section 11).6.2 Hali

13、de ions form complexes with some metals. Sincethe electrode responds only to free bromide ions, the presenceof any complexing agents lowers the measured concentrations.Concentrations of free metal ions causing a 10 % error of a1This test method is under the jurisdiction of ASTM Committee D19 on Wate

14、rand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved June 15, 2010. Published July 2010. Originallyapproved in 1952. Last previous edition approved in 2005 as D1246 05. DOI:10.1520/D1246-10.2For referenced ASTM standards, visit the ASTM

15、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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Ha

16、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.bromide concentration of 8.1 mg/L are bismuth+3, 80 mg/L;cadmium+2, 100 mg/L; lead+2, 1600 mg/L; tin+2, 2400 mg/L;and thallium+3, 4 mg/L.6.3 Chloride ion and hydroxide ion do not interfere whenpresent in the concentrations of u

17、p to 400 and 30 000 times thebromide concentration, respectively. There will be no interfer-ence from ammonia when present in concentrations twice thatof bromide, nor from thiosulfate 20 times as concentrated asbromide. Iodide is an interference at a concentration ratio aslow as 2 3 104. Mercury sho

18、uld be absent from samples.7. Apparatus7.1 pH Meter, capable of reading to 0.1 mV, or a selective-ion meter.7.2 Bromide Ion-Selective Electrode.7.3 Sleeve-Type Single-Junction Reference Electrode, filledwith manufacturers filling solution.7.4 Mixer, magnetic, with a TFE fluorocarbon-coated stir-ring

19、 bar.7.5 Laboratory Glassware.8. Reagents8.1 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 Society,where such speci

20、fications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of Water Unless otherwise indicated, referenceto water shall be understood to mean reagent

21、 water conformingto Specification D1193, Type I. 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 bias and precision of the test method. Type IIwater was specified at the time of round

22、 robin testing of thistest method.8.3 Ionic Strength Adjustor (42.5 g/100 mL NaNO3)In a100-mL volumetric flask, dissolve 42.5 g of sodium nitrate(NaNO3) in water and dilute to volume.8.4 Nickel Sulfate Solution, 1 MIn a 100 mL volumetricflask dissolve 26.3 g of nickel sulfate hexahydrate (NiSO46H2O)

23、 in water and dilute to volume.8.5 Sodium Bromide Standard Solution, 1000 mg/LIna1L volumetric flask dissolve 1.288 g dried sodium bromide inwater and dilute to volume. Alternatively, certified bromidestock solutions are commercially available through chemicalsupply vendors and may be used.8.6 Sodiu

24、m Bromide Standard Solutions, (100, 10, and 1mg/L)Dilute 1 volume of the 1000 mg/L bromide standardwith 9 volumes of water to prepare the 100 mg/L standard. Byfurther 1+9 serial dilutions, prepare the 10 and 1 mg/Lstandards.9. Sampling9.1 Collect the samples in accordance with Practice D1066and Prac

25、tices D3370, as applicable.10. Calibration and Standardization10.1 To 100 mL of the 1, 10, 100, and 1000 mg/L NaBrstandards add 2 mL of the ionic strength adjustor (ISA). If anysamples require treatment for interferences, prepare standardswith the same background.10.2 Connect and fill electrodes in

26、accordance with manu-facturers instructions.10.3 Transfer the 1 mg/L standard-ISAmixture to a 150 mLbeaker and stir gently using the magnetic mixer. Immerse theelectrodes in the solution and wait 2 min for the potential tostabilize. Record the value.10.4 Rinse electrodes thoroughly and repeat for th

27、e 10, 100,and 1000 mg/L standard-ISA mixtures. Wait 2 min and recordthe potential.10.5 The calibration curve is generated by plotting onsemilogarithmic graph paper, the potential observed versus theconcentration of the standard used. Note that volume correc-tions are incorporated into the calibratio

28、n, so that samplesanalyzed according to Section 11 of this test method can beread directly. Direct reading instruments may be used.11. Procedure11.1 To any sample containing sulfide or cyanide ion, add0.1 mL nickel sulfate solution to 100 mL sample.NOTE 1This concentration of nickel sulfate will rea

29、ct with 58 mg/Lsulfide and 117 mg/L cyanide.11.2 Transfer 100 mL sample to a 150 mL beaker and add 2mL ionic strength adjustor. Stir thoroughly for 1 min using themagnetic mixer.11.3 Immerse the electrodes in the sample-ISA mixture andwait 2 min for the potential to stabilize. Record the value.11.4

30、Read bromide concentration of the sample, in mg/L,directly from the calibration curve. Note that volume correc-tions are incorporated into the calibration.12. Precision and Bias412.1 PrecisionThe overall and single-operator precisionof this test method may be expressed as follows:12.1.1 For Reagent

31、Water:ST5 0.077X 1 1.10, coefficient of correlation 5 1.0SO5 0.067X 1 0.79, coefficient of correlation 5 1.012.1.2 For Water Matrices:ST5 0.064X 1 0.84, coefficient of correlation 5 1.0SO5 0.049X 1 0.09, coefficient of correlation 5 1.03Reagent Chemicals, American Chemical Society Specifications, Am

32、ericanChemical Society, 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. Pharmaceutical Convention, Inc. (

33、USPC), Rockville,MD.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1078.D1246 102where:ST= overall precision, mg/L,SO= single-operator precision, mg/L, andX = concentration of bromide determined.12.2 The selected water matr

34、ices included natural waters,ground waters, and tap water. These data on precision and biasmay not apply to waters of other matrices.12.3 BiasRecoveries of known amounts of bromide fromreagent water and selected water matrices were as shown inTable 1.12.4 This information is derived from round-robin

35、 testing,in which five laboratories, including eight operators, partici-pated. Of the eight sets of data ranked, as described in PracticeD2777, none was rejected. One operator submitted reagentwater data only. One outlier data point within each set was alsorejected. Four sample levels were run on th

36、ree days and blankswere obtained for the water used.12.5 This section on precision and bias conforms to PracticeD2777 77, which was in place at the time of collaborativetesting. Under the allowances made in 1.4 of PracticeD2777 08, these precision and bias data do meet existingrequirements for inter

37、laboratory studies of Committee D19 testmethods.13. Quality Control13.1 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 bromide.13.2 Calibration a

38、nd Calibration Verification13.2.1 Analyze at least three working standards containingconcentrations of bromide that bracket the expected sampleconcentration prior to analysis of samples to calibrate theinstrument.13.2.2 Verify instrument calibration after standardization byanalyzing a standard at th

39、e concentration of one of thecalibration standards. Alternately, the concentration of a mid-range standard should fall within 6 15 % of the knownconcentration.13.2.3 If calibration cannot be verified, recalibrate theinstrument.13.3 Initial Demonstration of Laboratory Capability13.3.1 If a laboratory

40、 has not performed the test before, or ifthere has been a major change in the measurement system, forexample, new analyst, new instrument, and so forth, a precisionand bias study must be performed to demonstrate laboratorycapability.13.3.2 Analyze seven replicates of a standard solutionprepared from

41、 an Independent Reference Material containing amid-range concentration of bromide. The matrix and chemistryof the solution should be equivalent to the solution used in thecollaborative study. Each replicate must be taken through thecomplete analytical test method including any sample preser-vation a

42、nd pretreatment steps.13.3.3 Calculate the mean and standard deviation of theseven values and compare to the acceptable ranges of bias insection 12.1. This study should be repeated until the recoveriesare within the limits given in section 12.1. If a concentrationother than the recommended concentra

43、tion is used, refer toPractice D5847 for information on applying the F test and t testin evaluating the acceptability of the mean and standarddeviation.13.4 Laboratory Control Sample (LCS)13.4.1 To ensure that the test method is in control, analyzea LCS containing a mid-range concentration of bromid

44、e witheach batch or 10 samples. If large numbers of samples areanalyzed in the batch, analyze the LCS after every 10 samples.The LCS must be taken through all of the steps of the analyticalmethod including sample preservation and pretreatment. Theresult obtained for the LCS shall fall within 6 15%of

45、theknown concentration.13.4.2 If the result is not within these limits, analysis ofsamples is halted until the problem is corrected, and either allthe samples in the batch must be reanalyzed, or the results mustbe qualified with an indication that they do not fall within theperformance criteria of t

46、he test method.13.5 Method Blank13.5.1 Analyze a reagent water test blank with each batch.The concentration of bromide found in the blank should be lessthan 0.5 times the lowest calibration standard. If the concen-tration of bromide is found above this level, analysis ofsamples is halted until the c

47、ontamination is eliminated, and ablank shows no contamination at or above this level, or theresults must be qualified with an indication that they do not fallwithin the performance criteria of the test method.13.6 Matrix Spike (MS)13.6.1 To check for interferences in the specific matrixbeing tested,

48、 perform a MS on at least one sample from eachbatch by spiking an aliquot of the sample with a knownconcentration of bromide and taking it through the analyticalmethod.13.6.2 The spike concentration plus the background concen-tration of bromide must not exceed the high calibrationstandard. The spike

49、 must produce a concentration in the spikedsample that is 2 to 5 times the bromide concentration in theunspiked sample, or 10 to 50 times the detection limit of thetest method, whichever is greater.13.6.3 Calculate the percent recovery of the spike (P) usingthe following formula:P 5 100 AVs1 V! BVs# / CVwhere:TABLE 1 Recoveries of Known Amounts of Bromide fromReagent Water and Selected Water MatricesAmountadded,mg/LAmountfound,mg/L6Bias,%StatisticallySignificant(95 % Con-fidenceLevel)Reagent 0.65 0.77 + 18.5 yesWater 1.00 1.19 + 19.0 no92.7 96.4 + 3.99 no864 85