ASTM D1971-2011 Standard Practices for Digestion of Water Samples for Determination of Metals by Flame Atomic Absorption Graphite Furnace Atomic Absorption Plasma Emission Spectros.pdf

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1、Designation:D197102 (Reapproved 2006) Designation: D1971 11Standard Practices forDigestion of Water Samples for Determination of Metals byFlame Atomic Absorption, Graphite Furnace AtomicAbsorption, Plasma Emission Spectroscopy, or PlasmaMass Spectrometry1This standard is issued under the fixed desig

2、nation D1971; 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 indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision o

3、r reapproval.1. Scope*1.1 Most atomic absorption and plasma emission spectroscopy, and plasma-mass spectrometric test methods require that themetals of interest be dissolved in a liquid phase before being introduced into the spectrophotometer. These practices describedigestion or dissolution procedu

4、res whereby analyte metals associated with the solid fraction of a sample can be brought intosolution for subsequent analysis. The following practices are included:SectionsPractice ADigestion with Mineral Acids andElevated Pressure8 through 13Practice BDigestion with Mineral Acids andHeating at Atmo

5、spheric Pressure14 through 19Practice CIn-bottle digestion with Mineral Acids 20 through 251.2 These practices have been demonstrated to be applicable to a wide variety of sample types and sample matrices, and in manycases, will give complete dissolution of the analyte metals of interest. They are b

6、y no means the only digestion proceduresavailable.1.3 The user of these practices should be cautioned that these practices may not completely dissolve all portions of a samplessolid phase and may not give complete recovery of the desired analyte metals. In these cases, other digestion techniques are

7、available that will effect complete dissolution of a sample. It is the users responsibility to ensure the validity of these practicesfor use on their particular sample matrix, for their metals of interest.1.4 This practice assumes that the criteria established in Guide D3856 can be met.1.5 These dig

8、estion procedures have been selected for their wide application, low cost, and ease of use.1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.7 This standard does not purport to address all of the safety concerns, if any,

9、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. Specific hazard statements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2D511

10、Test Methods for Calcium and Magnesium In WaterD857 Test Method for Aluminum in WaterD858 Test Methods for Manganese in WaterD1068 Test Methods for Iron in WaterD1129 Terminology Relating to Water D1192Guide for Equipment for Sampling Water and Steam in Closed ConduitsD1193 Specification for Reagent

11、 WaterD1687 Test Methods for Chromium in WaterD1688 Test Methods for Copper in Water1These practices are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.05 on Inorganic Constituents inWater.Current edition approved Dec. 15, 2006. Published

12、February 2007. Originally approved in 1991. Last previous edition approved in 2002 as D197102. DOI:10.1520/D1971-02R06.Current edition approved April 1, 2011. Published April 2011. Originally approved in 1991. Last previous edition approved in 2006 as D1971 02(2006). DOI:10.1520/D1971-11.2For refere

13、ncedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide th

14、e 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 all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standa

15、rd as published by ASTM is to be considered the official document.*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.D1691 Test Methods for Zinc in WaterD1886 Test Methods

16、 for Nickel in WaterD1976 Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission SpectroscopyD3370 Practices for Sampling Water from Closed ConduitsD3372 Test Method for Molybdenum in WaterD3557 Test Methods for Cadmium in WaterD3558 Test Methods for Cobalt in WaterD35

17、59 Test Methods for Lead in WaterD3645 Test Methods for Beryllium in WaterD3856 Guide for Good Laboratory Practices in Laboratories Engaged in Sampling and Analysis of WaterD3866 Test Methods for Silver in WaterD3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorptio

18、n SpectrophotometryD4190 Test Method for Elements in Water by Direct-Current Plasma Atomic Emission SpectroscopyD4191 Test Method for Sodium in Water by Atomic Absorption SpectrophotometryD4192 Test Method for Potassium in Water by Atomic Absorption SpectrophotometryD4309 Practice for Sample Digesti

19、on Using Closed Vessel Microwave Heating Technique for the Determination of Total Metalsin WaterD4691 Practice for Measuring Elements in Water by Flame Atomic Absorption SpectrophotometryD5673 Test Method for Elements in Water by Inductively Coupled PlasmaMass Spectrometry2.2 U.S. EPA Method:EPA-600

20、/4-79-020 Methods for Chemical Analysis of Water and Wastes3EPA-600/R-94/111 Methods for the Determination of Metals in Environmental SamplesSupplement 132.3 U.S. Geological Survey Method:U.S. Geological Survey Open File Report 96225: Methods of Analysis by the U.S. Geological Survey National Water

21、QualityLaboratoryIn-Bottle Acid Digestion of Whole Water SamplesQuality LaboratoryIn-Bottle Acid Digestion of Whole Water Samples443. Terminology3.1 Definitions: For definitions of terms used in these practices, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 dige

22、stiondigestion, ntreating a sample with the use of heat or elevated pressures, or both, usually in the presence ofchemical additives, to bring analytes of interest into solution or to remove interfering matrix components, or both.3.2.2 total recoverabletotal recoverable, nthe amount of a metal analy

23、te measurable by atomic absorption spectrophotometry,plasma emission spectroscopy or plasma mass spectrometry after applying the digestion procedure in either Practice A, PracticeB, or Practice C. The choice of Practice A, B, or C shall be noted in reporting resultant data.3.2.2.1 DiscussionThe choi

24、ce of Practice A, B, or C shall be noted in reporting resultant data.4. Significance and Use4.1 The determination of metals in water often requires the measurement of total (suspended and dissolved) metals as well assoluble (dissolved) metals. In such cases, consistent and dependable digestion proce

25、dures must be used so that data derived for thetotal metals content is reliable.4.2 The practices given are applicable to a wide variety of sample types for the purpose of preparing a sample for metalsanalyses by atomic absorption spectrophotometry or plasma emission spectroscopy (see Test Methods D

26、1976, D3919, D4691, andD4190) or plasma-mass spectrometry (See Test Method D5673) and have been shown to give good recovery in the followingmatrices: industrial effluents; waste water treatment plant influents, sludges, dewatered sludges, and effluents; river and lake waters;and plant and animal tis

27、sues. Elements which have shown good recovery include: copper, nickel, lead, zinc, cadmium, iron,manganese, magnesium, and calcium.4.2.1 Good recovery for the indicated sample types and metals may not be achieved at all times due to each samples uniquecharacteristics. Users must always validate the

28、practice for their particular samples.4.3 The analytical results achieved after applying these practices cannot necessarily be deemed as a measure of bioavailable orenvironmentally available elements.4.4 These three practices may not give the same recovery when applied to the same sample, nor will t

29、hey necessarily give thesame results as achieved using other digestion techniques. An alternate digestion technique is Practice D4309.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall be used throughout. Acids shall have a low-metal content or should be3Revised March 1983. Published by

30、the United States Environmental Protection Agency. Available from Superintendent of Documents, U.S. Government Printing Office,Washington, DC 20402.4Available from USGS National Center, 12201 Sunrise Valley Dr., Reston, VA 20192, USA.D1971 112doubly distilled and checked for purity. Unless otherwise

31、 indicated, it is intended that all reagents shall conform to theSpecifications of the Committee on Analytical Reagents of the American Chemical Society.5Other grades may be used, providedit is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the

32、accuracy of thedetermination.5.2 Purity of WaterUnless 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

33、permit its use without lessening the bias and precision of the determination.6. Hazards6.1 These practices involve the heating of solutions of mineral acids. Appropriate precautions shall be taken to protect theanalyst from these acids and heated containers. Heated samples and acids may splatter or

34、boil unexpectedly.7. Sampling7.1 As with all chemical assay procedures, the user of this practice shall ensure that all sample aliquot used are adequatelyrepresentative of the environmental situation being monitored.7.2 Appropriate sampling and subsampling techniques for particular environmental sam

35、ples can be found in other references.7.3Collect the sample in accordance with Specification D1192 and Practices7.3 Collect the sample in accordance with Practice D3370.PRACTICE ADIGESTION WITH MINERAL ACIDS ANDELEVATED PRESSURE8. Scope8.1 This practice presents a digestion technique that has broad

36、application and can be performed inexpensively with minimallabor, equipment, and space. In addition, this practice allows for many samples to be processed quickly and simultaneously underthe same conditions.9. Summary of Practice9.1 Samples are placed in loosely capped, heat-, and acidresistant cont

37、ainers with selected reagents and subjected to 121C and15 psig (103 kPa gage) for 30 min. After removing any particulate matter remaining, the digestate is ready for analysis by atomicabsorption spectrophotometry, plasma emission spectroscopy, or plasma-mass spectrometry.9.2 The practice may be foun

38、d to be more applicable to a particular sample or analytical scheme after appropriate modificationsof reagent addition, temperature, pressure, digestion time, or container selection. Any such modifications to this practice must bevalidated by the user.10. Apparatus10.1 Digestion Containers50 mL disp

39、osable polypropylene centrifuge tubes and 125 mL polypropylene reagent bottles withscrew caps have been used successfully. Any container that is not attacked by the digestion conditions, is sufficiently free of theanalyte(s) of interest, and can be loosely capped, may be used.10.2 Digestion Containe

40、r RackAny rack that will fit inside the autoclave, will hold the digestion containers securely, and isnot attacked by the conditions in the autoclave, may be used.10.3 AutoclaveAny autoclave or similar apparatus with a pressure chamber large enough to hold the desired number ofsamples and capable of

41、 achieving and holding 121C and 15 psig (103 kPa gage) for 30 min., may be employed. An autoclavewith automatic cycling is desirable. As the digesting samples release acidic fumes, the portions of the autoclave coming in contactwith these fumes should be constructed of acid resistant materials.NOTE

42、1Prolonged use of an autoclave with a stainless steel interior for this practice may result in discoloration of the autoclave walls. Thisdiscoloration has not been shown to cause any problems with autoclave operation. A commercially available autoclave with a stainless steel interior hasbeen in dail

43、y use for this practice, as well as for routine sterilization purposes, for ten years without any degradation of the autoclave or its performance.11. Interferences11.1 The interferences of this practice relate to the inability of the described procedure to quantitatively dissolve the analytemetals o

44、f interest in certain situations. These interferences can be either physical or chemical.11.2 Physical InterferencesIn some samples, the metals of interest are bound or occluded in a matrix that is impervious todissolution by the acids. This is most frequently encountered in geological and boiler wa

45、ter samples.5Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United St

46、ates Pharmacopeia and NationalFormulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.D1971 11311.3 Chemical InterferencesThe complete dissolution of a metal of interest may not occur due to the digestion conditionsbeing insufficiently rigorous for that particular metal. In other insta

47、nces, the chemical makeup of the sample may render thedigestion acids ineffective.12. Reagents12.1 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).12.2 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).13. Procedures13.1 In this section two types of digestion procedures are

48、described: one for liquid samples (see 13.2) and one for solid andsemi-solid samples (see 13.3).13.2 Liquid Samples:13.2.1 Using a sample volume from 40 to 100 mL, pipet an aliquot of sample, hydrochloric acid, and nitric acid into a digestioncontainer in the following ratio: 100 volumes sample to 5

49、 volumes HCl (sp gr 1.19) to 1 volume HNO3(sp gr 1.42).13.2.2 Swirl digestion container gently to mix contents.13.2.3 Loosely place caps on digestion containers and place digestion containers in rack.NOTE 2Caps should be attached securely enough so that they are not thrown off during autoclaving, but not so securely that gas is unable to movefreely in and out of the container.13.2.4 Place rack of digestion containers in autoclave and process for 30 min. at 121C and 15 psig (103 kPa gage).13.2.5 Remove digestion containers from autoclave; allow to cool