ASTM D1971-2016 Standard Practices for Digestion of Water Samples for Determination of Metals by Flame Atomic Absorption Graphite Furnace Atomic Absorption Plasma Emission Spectros.pdf

1、Designation: D1971 11D1971 16Standard 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 designation D1971; the number immed

2、iately 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 or reapproval.1. Scope*1.1 Most

3、 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 procedures whereby analyte metals ass

4、ociated 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 ADigestion with Mineral Acids andElevated Pressure8 through 13Practice BDigest

5、ion with Mineral Acids andHeating at Atmospheric Pressure14 through 19Practice BDigestion with Mineral Acids andHeating at Atmospheric Pressure14 through 19Practice CIn-bottle digestion with Mineral Acids 20 through 25Practice CIn-Bottle Digestion with Mineral Acids 20 through 251.2 These practices

6、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 by no means the only digestion proceduresavailable.1.3 The user of these practices should be cautioned that thes

7、e 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 areavailable that will effect complete dissolution of a sample. It is the users responsibility to ensure the valid

8、ity 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 digestion procedures have been selected for their wide application, low cost, and ease of use.1.6 The values state

9、d in SI units are to be regarded as the standard. The values given in parentheses are for informationonly.mathematical conversion to inch-pound units that are provided for information only and are not considered standard.1.7 This standard does not purport to address all of the safety concerns, if an

10、y, 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:2D5

11、11 Test Methods for Calcium and Magnesium In WaterD857 Test Method for Aluminum in Water1 These 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 April 1, 2011June 1,

12、 2016. Published April 2011July 2016. Originally approved in 1991. Last previous edition approved in 20062011 asD1971 02D1971 11.(2006). DOI: 10.1520/D1971-11.10.1520/D1971-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For

13、 Annual Book of ASTM Standardsvolume information, 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 no

14、t 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 standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the en

15、d of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D858 Test Methods for Manganese in WaterD1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1687 Test Methods f

16、or Chromium in WaterD1688 Test Methods for Copper in WaterD1691 Test Methods for Zinc in WaterD1886 Test Methods for Nickel in WaterD1976 Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission SpectroscopyD2972 Test Methods for Arsenic in WaterD3082 Test Method for Bor

17、on in WaterD3370 Practices for Sampling Water from Closed ConduitsD3372 Test Method for Molybdenum in WaterD3373 Test Method for Vanadium in WaterD3557 Test Methods for Cadmium in WaterD3558 Test Methods for Cobalt in WaterD3559 Test Methods for Lead in WaterD3645 Test Methods for Beryllium in Water

18、D3697 Test Method for Antimony in WaterD3859 Test Methods for Selenium in WaterD3856 Guide for Management Systems in Laboratories Engaged in Analysis of WaterD3866 Test Methods for Silver in WaterD3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotom

19、etryD3920 Test Method for Strontium in WaterD4190 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 Pr

20、actice for Sample Digestion Using Closed Vessel Microwave Heating Technique for the Determination of Total Metalsin WaterD4382 Test Method for Barium in Water, Atomic Absorption Spectrophotometry, Graphite FurnaceD4691 Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotom

21、etryD5673 Test Method for Elements in Water by Inductively Coupled PlasmaMass Spectrometry2.2 U.S. EPA Method:3EPA-600/4-79-020 Methods for Chemical Analysis of Water and Wastes, Revised March 1983EPA-600/R-94/111 Methods for the Determination of Metals in Environmental SamplesSupplement 132.3 U.S.

22、Geological Survey USGS Method:4U.S. Geological Survey USGS Open File Report 96225:96225 Methods of Analysis by the U.S. Geological Survey NationalWater Quality LaboratoryIn-Bottle Acid Digestion of Whole Water Samples3. Terminology3.1 Definitions: For definitions of terms used in these practices, re

23、fer to Terminology D1129.3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 digestion, ntreating a sample with the use of heat or elevated pressures, or both, usually in the presence of chemicaladd

24、itives, to bring analytes of interest into solution or to remove interfering matrix components, or both.3.2.2 total recoverable, nthe amount of a descriptive term relating to the metal forms recovered in the acid-digestionprocedures resulting in a metal analyte measurable by atomic absorption spectr

25、ophotometry, plasma emission spectroscopy orplasma mass spectrometry after applying the digestion procedure in either Practice A, Practice B, or Practice C. The choice ofPractice A, B, or C shall be noted in reporting resultant data.3.2.2.1 Discussion3 Revised March 1983. Published by the United Sta

26、tes Environmental ProtectionAgency.Available from Superintendent of Documents, U.S. Government Printing Office,Washington, DC 20402.Available from United States Environmental Protection Agency (EPA), William Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington,DC 20460, http:/www.epa.gov.

27、4 Available from USGS U.S. Geological Survey (USGS) National Center, 12201 Sunrise Valley Dr., Reston, VA 20192, USA.https:/www.usgs.gov.D1971 162The choice 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 require

28、s the measurement of total (suspended and dissolved) metals as well assoluble (dissolved) metals. In such cases, consistent and dependable digestion procedures 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

29、 types for the purpose of preparing a sample for metalsanalyses by atomic absorption spectrophotometry or plasma emission spectroscopy (see Test MethodsMethod D1976, PracticeD3919, Practice D4691, and Test Method D4190) or plasma-mass spectrometry (See(see Test Method D5673) and have beenshown to gi

30、ve good recovery in the following matrices: industrial effluents; waste water treatment plant influents, sludges,dewatered sludges, and effluents; river and lake waters; and plant and animal tissues. Elements which have shown good recoveryinclude: copper, nickel, lead, zinc, cadmium, iron, manganese

31、, 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 practice for their particular samples.4.3 The analytical results achieved after applying these practices c

32、annot 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 they necessarily give thesame results as achieved using other digestion techniques. An alternate digestion

33、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 bedoubly distilled and checked for purity. Unless otherwise indicated, it is intended that all reagents shall conform to theSpecifications of

34、the Committee on Analytical Reagents of the American Chemical Society.5 Other grades may be used, providedit is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of thedetermination.5.2 Purity of WaterUnless otherwise indicated, refere

35、nces 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 lessening the bias and precision of the determination.6. Ha

36、zards6.1 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 boil unexpectedly.7. Sampling7.1 As with all chemical assay procedures, the user o

37、f 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 samples can be found in other references.7.3 Collect the sample in accordance with Pr

38、acticePractices D3370.PRACTICE ADIGESTION WITH MINERAL ACIDS MINERAL ACIDS ANDELEVATED PRESSURE8. Scope8.1 This practice presents a digestion technique that has broad application and can be performed inexpensively with minimallabor, equipment, and space. In addition, this practice allows for many sa

39、mples to be processed quickly and simultaneously underthe same conditions.9. Summary of Practice9.1 Samples are placed in loosely capped, heat-, and acidresistant containers with selected reagents and subjected to 121C and15 psig (103 kPa gage) 103 kPa (15 psi) for 30 min. After removing any particu

40、late matter remaining, the digestate is ready foranalysis by atomic absorption spectrophotometry, plasma emission spectroscopy, or plasma-mass spectrometry.5 Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of rea

41、gents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.D1971 1639.2 The practice may be found to be more appli

42、cable 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 disposable polypropyle

43、ne 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 Container RackAny rack tha

44、t 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 achieving and hol

45、ding 121C and 15 psig (103 kPa gage) 103 kPa (15 psi) for 30 min., may be employed.An autoclave with automatic cycling is desirable. As the digesting samples release acidic fumes, the portions of the autoclavecoming in contact with these fumes should be constructed of acid resistant materials.NOTE 1

46、Prolonged 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 daily

47、 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 of

48、 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 wat

49、er samples.11.3 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 instances, 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).12. Reagents and Materials12.1 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).12.2 Nitric Acid (sp gr