ASTM D1691-2012 Standard Test Methods for Zinc in Water《水中锌的标准试验方法》.pdf

1、Designation: D1691 02 (Reapproved 2007)1D1691 12Standard Test Methods forZinc in Water1This standard is issued under the fixed designation D1691; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number i

2、n parentheses indicates 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 NOTEPractice D2777 98 was editorially changed throughout to D2777 06 in

3、August 2007.1. Scope Scope*1.1 These test methods cover the determination of zinc in water. Two test methods are given as follows:Test Method ConcentrationRangeSectionsAAtomic Absorption, Direct 0.05 to 2 mg/L 8-16BAtomic Absorption,Chelation-Extraction20 to 200 g/L 17-251.2 Either dissolved or tota

4、l recoverable zinc may be determined.1.3 These test methods have been used successfully with reagent grade water. See the specific test method for applicability toother matrices. It is the users responsibility to assure the validity of these test methods in other matrices.1.4 The values stated in ei

5、ther SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem are mathematical conversions and may not be exact equivalents; therefore, each system shall be used independently of theother.1.5 This standard does not purport to address all of the safety c

6、oncerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see Section 6 and Note 56, Note 810, and Note 131

7、6.1.6 Two former colorimetric test methods were discontinued. Refer to Appendix X1 for historical information.2. Referenced Documents2.1 ASTM Standards:2D858 Test Methods for Manganese in WaterD1066 Practice for Sampling SteamD1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD11

8、92 Guide for Equipment for Sampling Water and Steam in Closed Conduits (Withdrawn 2003)3D1193 Specification for Reagent WaterD1687 Test Methods for Chromium in WaterD1688 Test Methods for Copper in WaterD1886 Test Methods for Nickel in WaterD2777 Practice for Determination of Precision and Bias of A

9、pplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3557 Test Methods for Cadmium in WaterD3558 Test Methods for Cobalt in WaterD3559 Test Methods for Lead in WaterD4841 Practice for Estimation of Holding Time for Water Samples Containing Organic a

10、nd Inorganic Constituents1 These test methods are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Aug. 1, 2007Sept. 1, 2012. Published August 2007September 2012. Originally appro

11、ved in 1959. Last previous edition approved in 2002 asD1691 02.D1691 02(2007)E01. DOI: 10.1520/D1691-02R07E01.10.1520/D1691-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,

12、 refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict al

13、l changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 1

14、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis3. Terminology3.1 DefinitionsFor definitions of terms used in these tes

15、t methods, refer to Terminology D1129.3.2 Definitions:3.2.1 total recoverable zinczinc, nan arbitrary analytical term relating to the recoverable form of zinc that is determinableby the digestion method whichthat is included in the Procedure.4. Significance and Use4.1 Zinc is an essential and benefi

16、cial element in body growth. Concentrations above 5 mg/L can cause a bitter astringent tasteand opalescence in alkaline waters. The zinc concentration of U.S. drinking waters varies between 0.06 and 7.0 mg/L with a meanof 1.33 mg/L. Zinc most commonly enters the domestic water supply from deteriorat

17、ion of galvanized iron and dezincification ofbrass. Zinc in water also may result from industrial water pollution.35. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conformto the specifications of the Commi

18、ttee on Analytical Reagents of the American Chemical Society, where such specifications areavailable.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.5.2 Purity of WaterUn

19、less otherwise indicated, references to water shall be understood to mean reagent water conforming toSpecification D1193, Type I. Other reagent water types may be used, provided it is first ascertained that the water is of sufficientlyhigh purity to permit its use without adversely affecting the bia

20、s and precision of the test method. Type II water was specified atthe time of round-robin testing of this test method.6. Hazards6.1 Although zinc is nontoxic to man, these test methods require the use of certain other toxic and hazardous reagents andmaterials. Each should be used with care and exert

21、ing proper precautions.7. Sampling7.1 Collect the sample in accordance with Practice D1066, Specification D1192, and Practices D3370, as applicable.7.2 Samples shall be preserved with nitric acid (HNO3) (sp gr 1.42) to a pH of 2 or less immediately at the time of collection,normally about 2 mL/L of

22、HNO3. If only dissolved zinc is to be determined, the sample, shall be filtered through a 0.45-mmembrane filter before acidification. The holding time for samples may be calculated in accordance with Practice D4841.NOTE 1Alternatively, the pH may be adjusted in the laboratory if the sample is return

23、ed within 14 days. This could reduce hazards of working withacids in the field when appropriate.TEST METHOD AATOMIC ABSORPTION, DIRECT8. Scope8.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and wastewaters.8.2 This test method is applicable in the

24、 range from 0.05 to 2.0 mg/L of zinc. The range may be extended to concentrationsgreater than 2.0 mg/L by dilution of the sample.8.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water, lakewater, refinery effluent. The information o

25、n precision and bias may not apply to other waters.9. Summary of Test Method9.1 Zinc is determined by atomic absorption spectrophotometry. Dissolved zinc is determined by aspirating a portion of thefiltered and preserved sample directly with no pretreatment. Total recoverable zinc is determined by a

26、spirating the samplefollowing hydrochloric-nitric acid digestion and filtration. The same digestion procedure is used to determine total recoverablecadmium (Test Methods D3557), chromium, (Test Methods D1687), cobalt (Test Methods D3558), copper (Test Methods D1688),iron (Test Methods D1068), lead (

27、Test Methods D3559), manganese (Test Methods D858), and nickel (Test Methods D1886).3 “Standard Methods for the Examination of Water and Wastewater,” 16th edition, 1985, APHA, AWWA-WPCF.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Sugg

28、estions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D1691 12210. Interferences1

29、0.1 Sodium, potassium, sulfate, and chloride (9000 mg/L each), calcium and magnesium (4000 mg/L each), nitrate (2000mg/L), and cadmium, lead, copper, nickel, cobalt, and chromium (10 mg/L each) do not interfere.10.2 Background correction or a chelation-extraction procedure (see Test Method B) may be

30、 necessary to determine low levelsof zinc in some waters.NOTE 2Instrument manufacturers instructions for use of the specific correction technique should be followed.11. Apparatus11.1 Atomic Absorption Spectrophotometer , for use at 213.9 nm.NOTE 3The manufacturers instructions should be followed for

31、 all instrumental parameters. Wavelengths other than 213.9 nm may be used if theyhave been determined to be equally suitable.11.1.1 Zinc Light SourceHollow-cathode lamps or electrodeless discharge lamps have been found satisfactory.11.2 OxidantSee 12.6.11.3 FuelSee 12.7.11.4 Pressure-Reducing Valves

32、The supplies of fuel and oxidant shall be maintained at pressures somewhat higher than thecontrolled operating pressure of the instrument by suitable valves.12. Reagents and Materials12.1 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).NOTE 4If the reagent blank concentration is g

33、reater than the method detection limit, distill the HCl or use a spectrograde acid. WarningWhen HClis distilled an azeotropic mixture is obtained (approximately 6 N HCl). Therefore, whenever concentrated HCl is specified in the preparation of a reagentor in the procedure, use double the amount speci

34、fied if a distilled acid is used.12.2 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).NOTE 5If the reagent blank concentration is greater than the method detection limit, distill the HNO3 or use a trace metal grade acid.12.3 Nitric Acid (1 +499)Add 1 volume of HNO3 (sp gr 1.42) to 499 volume

35、s of water.12.4 Zinc Solution, Stock (1 mL = 1.0 mg Zn)Dissolve 1.245 g of zinc oxide (ZnO) in a mixture of 10 mL of HNO3 (sp gr1.42) and 10 mLof water. Dilute to 1 Lwith water.Apurchased zinc stock solution of appropriate known purity is also acceptable.12.5 Zinc Solution, Standard (1 mL = 0.1 mg Z

36、n)Dilute 100.0 mL of the zinc stock solution and 1 mL of HNO3 (sp gr 1.42)to 1 L with water.12.6 Oxidant:12.6.1 Air, which has been passed through a suitable filter to remove oil, water, and other foreign substances, is the usualoxidant.12.7 Fuel:12.7.1 AcetyleneStandard, commercially available acet

37、ylene is the usual fuel.Acetone, always present in acetylene cylinders,can affect analytical results. The cylinder should be replaced at 50 psig (345 kPa).345 kPa (50 psi).NOTE 6Warning: “Purified” grade acetylene containing a special proprietary solvent rather than acetone should not be used with p

38、oly(vinyl chloride)tubing as weakening of the tubing walls can cause a potentially hazardous situation.13. Standardization13.1 Prepare 100 mL each of a blank and at least four standard solutions to bracket the expected zinc concentration range ofthe samples to be analyzed by diluting the standard zi

39、nc solution (12.5) with HNO3 (1 +499). Prepare the standards each time thetest is to be performed and select so as to give zero, middle, and maximum points for an analytical curve.13.2 When determining total recoverable zinc, add 0.5 mL of HNO3 (sp gr 1.42) to each blank and standard solution andpro

40、ceed as directed in 14.2-14.4.After the digestion of the blank and standard solutions has been completed in 14.4, return to 13.3to complete the standardization for total recoverable determinations. To determine dissolved zinc, proceed with 13.3.13.3 Aspirate the blank and standards, and record the a

41、bsorbance of each at 213.9 nm. Aspirate HNO3 (1 +499) between eachstandard.13.4 Prepare an analytical curve by plotting the absorbance versus concentration for each standard. Alternatively, read directlyin concentration from the instrument.D1691 12314. Procedure14.1 Measure 100.0 mL of a well-mixed

42、acidified sample into a 125-mL beaker or flask.NOTE 7If only dissolved zinc is to be determined, start with 14.5.14.2 Add 5 mL of HCl (sp gr 1.19) to each sample.14.3 Heat the samples on a steam bath or hotplate in a well-ventilated hood until the volume has been reduced to 15 to 20 mL,making certai

43、n that the samples do not boil.NOTE 8For samples with appreciable amounts of suspended matter or dissolved solids, the amount of reduction in the volume is left to the discretionof the analyst.NOTE 9Many laboratories have found block digestion systems a useful way to digest samples for trace metals

44、analysis. Systems typically consist ofeither a metal or graphite block with wells to hold digestion tubes. The block temperature controller must be able to maintain uniformity of temperatureacross all positions of the block. For trace metals analysis, the digestion tubes should be constructed of pol

45、ypropylene and have a volume accuracy ofat least 0.5%. All lots of tubes should come with a certificate of analysis to demonstrate suitability for their intended purpose.14.4 Cool and filter the samples through a suitable filter, such as fine-textured, acid-washed, ashless paper, into 100-mLvolumetr

46、ic flasks. Wash the filter paper two or three times with water and adjust to volume.14.5 Aspirate each filtered and acidified sample and standard and determine its absorbance or concentration at 213.9 nm.Atomize HNO3 (1 +499) between each sample and standard.15. Calculation15.1 Calculate the concent

47、ration of zinc in each sample, in milligrams per litre, using the analytical curve prepared in 13.4 orread directly in concentration.16. Precision and Bias516.1 The overall precision and bias of this test method, within its designated range, is shown in Table 1.16.2 These collaborative test data wer

48、e obtained from eleven laboratories on reagent grade, river, lake, ground and effluentwaters. For other waters these data may not apply.16.3 Precision and bias for this test method conform to Practice D2777 77, which was in place at the time of collaborativetesting. Under the allowances made in 1.4

49、of Practice D2777 06, 08, these precision and bias data do meet existingrequirements for interlaboratory studies of Committee D19 test methods.TEST METHOD BATOMIC ABSORPTION, CHELATIONEXTRACTION17. Scope17.1 This test method covers the determination of dissolved and total recoverable zinc in most waters and brines.17.2 This test method is applicable in the range from 20 to 200 g/L of zinc.17.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water,lake water, refiner