ASTM D516-2007 Standard Test Method for Sulfate Ion in Water《水中硫酸盐离子的标准试验方法》.pdf

1、Designation: D 516 07Standard Test Method forSulfate Ion in Water1This standard is issued under the fixed designation D 516; 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 (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. Scope1.1 This turbidimetric test method covers the determinationof sulfate in water in the

3、range from 5 to 40 mg/Lof sulfate ion(SO4).1.2 This test method was used successfully with drinking,ground, and surface waters. It is the users responsibility toensure the validity of this test method for waters of untestedmatrices.1.3 Former gravimetric and volumetric test methods havebeen disconti

4、nued. Refer to Appendix X1 for historical infor-mation.1.4 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regula

5、torylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1066 Practice for Sampling SteamD 1129 Terminology Relating to WaterD 1192 Guide for Equipment for Sampling Water andSteam in Closed Conduits3D 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision

6、 and Bias ofApplicable Test 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 AnalysisE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by Molecular Abso

7、rption SpectrometryE 275 Practice for Describing and Measuring Performanceof Ultraviolet, Visible, and Near-Infrared Spectrophotom-eters3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129.4. Summary of Test Method4.1 Sulfate ion is converted to

8、a barium sulfate suspensionunder controlled conditions.Asolution containing glycerin andsodium chloride is added to stabilize the suspension andminimize interferences. The resulting turbidity is determinedby a nephelometer, spectrophotometer, or photoelectric colo-rimeter and compared to a curve pre

9、pared from standard sulfatesolutions.5. Significance and Use5.1 The determination of sulfate is important because it hasbeen reported that when this ion is present in excess of about250 mg/L in drinking water, it causes a cathartic action(especially in children) in the presence of sodium and magne-s

10、ium, and gives a bad taste to the water.6. Interferences6.1 Insoluble suspended matter in the sample must beremoved. Dark colors that can not be compensated for in theprocedure interfere with the measurement of suspended bariumsulfate (BaSO4).6.2 Polyphosphates as low as 1 mg/L will inhibit bariumsu

11、lfate precipitation causing a negative interference. Phospho-nates present in low concentrations, depending on the type ofphosphonate, will also cause a negative interference. Silica inexcess of 500 mg/L may precipitate along with the bariumsulfate causing a positive interference. Chloride in excess

12、 of5000 mg/L will cause a negative interference. Aluminum,polymers, and large quantities of organic material present inthe test sample may cause the barium sulfate to precipitatenonuniformly. In the presence of organic matter certain bacte-ria may reduce sulfate to sulfide. To minimize the action of

13、sulfate reducing bacteria, samples should be refrigerated at 4Cwhen the presence of such bacteria is suspected.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved

14、Aug. 1, 2007. Published September 2007. Originallyapproved in 1938. Last previous edition approved in 2002 as D 516 02.2For 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

15、to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.3 Although other ions normally found in water do notappear to interfere, the formation of the barium sulfate suspe

16、n-sion is very critical. Determinations that are in doubt may bechecked by a gravimetric method in some cases, or by theprocedure suggested in Note 2.7. Apparatus7.1 PhotometerOne of the following which are given inorder of preference.7.1.1 Nephelometer or turbidimeter;7.1.2 Spectrophotometer for us

17、e at 420 nm with light path of4to5cm;7.1.3 Filter photometer with a violet filter having a maxi-mum near 420 nm and a light path of 4 to 5 cm.7.2 Stopwatch, if the magnetic stirrer is not equipped withan accurate timer.7.3 Measuring Spoon, capacity 0.2 to 0.3 mL.7.4 Filter photometers and photometri

18、c practices prescribedin this test method shall conform to Practice E60; spectropho-tometer practices shall conform to Practice E 275.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the s

19、pecifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society.4Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise in

20、dicated, referenceto water shall be understood to mean reagent water conformingto Specification D 1193, 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 precision and bias of th

21、e test method. Type IIwater was specified at the time of round robin testing of thistest method.8.3 Barium ChlorideCrystals of barium chloride(BaCl22H2O) screened to 20 to 30 mesh. To prepare in thelaboratory, spread crystals over a large watch glass, desiccatefor 24 h, screen to remove any crystals

22、 that are not 20 to 30mesh, and store in a clean, dry jar.8.4 Conditioning ReagentPlace 30 mL of concentratedhydrochloric acid (HCl, sp gr 1.19), 300 mLreagent water, 100mL 95 % ethanol or isopropanol and 75 g sodium chloride(NaCl) in a container. Add 50 mL glycerol and mix.8.5 Sulfate Solution, Sta

23、ndard (1 mL = 0.100 mg SO4)Dissolve 0.1479 g of anhydrous sodium sulfate (Na2SO4)inwater, and dilute with water to 1 L in a volumetric flask. Apurchased stock solution of adequate purity is also acceptable.9. Sampling9.1 Collect the sample in accordance with Practice D 1066,Specification D 1192, and

24、 Practices D 3370, as applicable.10. Calibration10.1 Follow the procedure given in Section 11, usingappropriate amounts of the standard sulfate solution preparedin accordance with 8.5 and prepare a calibration curve showingsulfate ion content in milligrams per litre plotted against thecorresponding

25、photometer readings (Note 1). Prepare standardsby diluting with water 0.0, 5.0, 10.0, 15.0, 20.0, 30.0, and 40.0mL of standard sulfate solution to 100-mL volumes in volu-metric flasks. These solutions will have sulfate ion concentra-tions of 0.0, 5.0, 10.0, 15.0, 20.0, 30.0, and 40.0 mg/L (ppm),resp

26、ectively.NOTE 1A separate calibration curve must be prepared for eachphotometer and a new curve must be prepared if it is necessary to changethe cell, lamp, or filter, or if any other alterations of instrument or reagentsare made. Check the curve with each series of tests by running two ormore solut

27、ions of known sulfate concentrations.11. Procedure11.1 Filter the sample if it is turbid through a 0.45-mmembrane and adjust the temperature to between 15 and 30C.11.2 Pipette into a 250-mL beaker 100 mL or less of theclear sample containing between 0.5 and 4 mg of sulfate ion(Note 2). Dilute to 100

28、 mL with water if required, and add 5.0mL of conditioning reagent (Note 1).NOTE 2The solubility of BaSO4is such that difficulty may beexperienced in the determination of sulfate concentrations below about 5mg/L (ppm). This can be overcome by concentrating the sample or byadding 5 mL of standard sulf

29、ate solution (1 mL = 0.100 mg SO4)tothesample before diluting to 100 mL. This will add 0.5 mg SO4to the sample,which must be subtracted from the final result.11.3 Mix in the stirring apparatus.11.4 While the solution is being stirred, add a measuredspoonful of BaCl2crystals (0.3 g) and begin timing

30、immedi-ately.11.5 Stir exactly 1.0 min at constant speed.NOTE 3The stirring should be at a constant rate in all determinations.The use of a magnetic stirrer has been found satisfactory for this purpose.11.6 Immediately after the stirring period has ended, poursolution into the cell and measure the t

31、urbidity at 30-s intervalsfor 4 min. Record the maximum reading obtained in the 4-minperiod.11.7 If the sample contains color or turbidity, run a sampleblank using the procedure 11.2 through 11.6 without theaddition of the barium chloride.11.8 If interferences are suspected, dilute the sample with a

32、nequal volume of water, and determine the sulfate concentrationagain. If the value so determined is one half that in theundiluted sample, interferences may be assumed to be absent.12. Calculation12.1 Convert the photometer readings obtained with thesample to milligrams per litre sulfate ion (SO4) by

33、 use of thecalibration curve described in Section 10.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd.,

34、Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D51607213. Precision and Bias513.1 The precision and bias data presented in this testmethod meet the requirements of Practice D 2777 86.13.2 The overall and single-

35、operator precision of the testmethod, within its designated range, varies with the quantitybeing tested according to Table 1 for reagent water and Table2 for drinking, ground, and surface waters.13.2.1 Seven laboratories participated in the round robin atthree levels in triplicate, making a total of

36、 21 observations ateach level for reagent water and for matrix water (drinking,ground, and surface water).13.3 Recoveries of known amounts of sulfate from reagentwater and drinking, ground, and surface waters are as shown inTable 3.13.3.1 A table for estimating the bias of the test methodthrough its

37、 applicable concentration range can be found inTable 4.13.3.2 These collaborative test data were obtained on re-agent grade water and natural waters. For other matrices, thesedata may not apply.13.4 Precision and bias for this test method conforms toPractice D 2777 86, which was in place at the time

38、 ofcollaborative testing. Under the allowances made in 1.4 ofD 2777 06, these precision and bias data do meet existingrequirements for interlaboratory studies of Committee D19 testmethods.14. Quality Control (QC)14.1 The following quality control information is recom-mended for the determination of

39、sulfate ion in water.14.1.1 The instrument should be calibrated using a mini-mum of four calibration standards and a calibration blank. Thecalibration correlation coefficient shall be equal to or greaterthan 0.990. In addition to the initial calibration blank, acalibration blank should be analyzed a

40、t the end of the batch runto ensure contamination ws not a problem during the batchanalysis.14.1.2 An instrument check standard should be analyzed ata minimum frequency of 10 % throughout the batch analysis.The value of the instrument check standard should fall between80 and 120 % of the true value.

41、14.1.3 Two method blanks should be prepared ensuring thatan adequate method blank volume is present for a minimum ofseven repetitive analysis. The standard deviation of the methodblank is used to determine the minimum detectable concentra-tion of each sample and control in the batch.14.1.4 A laborat

42、ory control sample should be analyzed witheach batch of samples at a minimum frequency of 10 %.14.1.5 If the QC for the sample batch is not within theestablished control limits, reanalyze the samples or qualify theresults with the appropriate flags, or both (See PracticeD 5847).14.1.6 Blind control

43、samples should be submitted by anoutside agency in order to determine the laboratory perfor-mance capabilities.15. Keywords15.1 drinking water; ground water; sulfate; surface water;turbidimetric5Supporting data are available from ASTM. Request RR:D-19-1145.TABLE 1 Overall (ST) and Single-Operator (S

44、O) StandardDeviations Against Mean Concentration for InterlaboratoryRecovery of Sulfate from Reagent WaterAMean Concentration (x),mg/LStandard Deviation, mg/LSTSO6.6 0.5 0.120.4 1.0 0.463.7 2.5 1.3AThe test method is linear to 40 mg/L. Testing at the 63.9 level wasaccomplished through dilution as de

45、scribed in 11.2.TABLE 2 Overall (ST) and Single-Operator (SO) StandardDeviations Against Mean Concentration for InterlaboratoryRecovery of Sulfate from Drinking, Ground, and Surface WaterAMean Concentration (x),mg/LStandard Deviation, mg/LSTSO6.9 0.7 0.520.2 2.2 1.863.3 4.5 1.6AThe test method is li

46、near to 40 mg/L. Testing at the 63.9 level wasaccomplished through dilution as described in 11.2.TABLE 3 Determination of BiasAAmountAdded,mg/LAmountFound,mg/L6Bias 6% BiasStatisticallySignificantat 5 %Level (at60.05)Reagent water 20.863.9A7.020.463.7A6.60.40.20.41.9 %0.2 %5.3 %nononoDrinking, groun

47、dand surface water20.863.9A7.020.263.3A6.90.60.60.12.7 %0.9 %1.8 %nononoAThe test method is linear to 40 mg/L. Testing at the 63.9 level wasaccomplished through dilution as described in 11.2.TABLE 4 Mean Sulfate Recovery Against Concentration Addedwith Overall Standard Deviation Shown for Interlabor

48、atoryExperimental Recovery of Sulfate from Reagent Waterand Drinking, Ground, and Surface WaterASulfate Added,mg/LMean Sulfate Recovery (x), mg/LReagent Water ( ST) Matrix Water ( SO)7.0 6.6 (0.5) 6.9 (0.7)20.8 20.4 (1.0) 20.2 (2.2)63.9 63.7 (2.5) 63.3 (4.5)AThe test method is linear to 40 mg/L. Tes

49、ting at the 63.9 level wasaccomplished through dilution as described in 11.2.D516073APPENDIX(Nonmandatory Information)X1. RATIONALE FOR DISCONTINUATION OF METHODSX1.1 Gravimetric:X1.1.1 This test method was discontinued in 1988. The testmethod may be found in the 1988 Annual Book of ASTMStandards, Vol 11.01. The test method was originally issued in1938.X1.1.2 This test method covers the determination of sulfatein water and wastewater. Samples containing from 20 to 100mg/L of sulfate may be analyzed.X1.1.3 Sulfate is precipitated and weighte