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2、n American National StandardStandard Practices forDigestion of Water Samples for Determination of Metals by Flame Atomic Absorption, Graphite Furnace Atomic Absorption, Plasma Emission Spectroscopy, or PlasmaMass Spectrometry1This standard is issued under the fixed designation D 1971; the number imm
3、ediately 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 Mo
4、st atomic absorption and plasma emission spectros- copy, and plasma-mass spectrometric test methods require that the metals of interest be dissolved in a liquid phase before being introduced into the spectrophotometer. These practices describe digestion or dissolution procedures whereby analyte meta
5、ls associated with the solid fraction of a sample can be brought into solution for subsequent analysis. The following practices are included:Sections1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the responsibility of the user of this
6、standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. Specific hazard statements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:D 511 Test Methods for Calcium and Magnesium in Water2Practice ADigest
7、ion with Mineral Acids andElevated PressurePractice BDigestion with Mineral Acids andHeating at Atmospheric Pressure8 through 1314 through 19D 857 Test Methods for Aluminum in Water2D 858 Test Methods for Manganese in Water2D 1068 Test Methods for Iron in Water2Practice CIn-bottle digestion with Min
8、eral Acids20 through 251.2 These practices have been demonstrated to be applicable to a wide variety of sample types and sample matrices, and in many cases, will give complete dissolution of the analyte metals of interest. They are by no means the only digestion procedures available.1.3 The user of
9、these practices should be cautioned that these practices may not completely dissolve all portions of a samples solid phase and may not give complete recovery of the desired analyte metals. In these cases, other digestion techniques are available that will effect complete dissolution ofa sample. It i
10、s the users responsibility to ensure the validity of these practices for use on their particular sample matrix, for their metals of interest.1.4 This practice assumes that the criteria established inGuide D 3856 can be met.1.5 These digestion procedures have been selected for their wide application,
11、 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 These practices are under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic C
12、onstituents in Water.D 1129 Terminology Relating to Water2D 1192 Specification for Equipment for Sampling Water and Steam in Closed Conduits2D 1193 Specification for Reagent Water2D 1687 Test Methods for Chromium in Water2D 1688 Test Methods for Copper in Water2D 1691 Test Methods for Zinc in Water2
13、D 1886 Test Methods for Nickel in Water2D 1976 Test Method for Elements in Water by Inductively- Coupled Argon Plasma Atomic Emission Spectroscopy2D 3370 Practices for Sampling Water from Closed Con- duits2D 3372 Test Method for Molybdenum in Water2D 3557 Test Methods for Cadmium in WaterD 3558 Test
14、 Methods for Cobalt in Water2D 3559 Test Method for Lead in Water2D 3645 Test Method for Beryllium in Water2D 3856 Guide for Good Laboratory Practices in Laborato- ries Engaged in Sampling and Analysis of Water2D 3866 Test Methods for Silver in Water2D 3919 Practices for Measuring Trace Elements in
15、Water byGraphite Furnace Atomic Absorption Spectrophotometry2D 4190 Test Method for Elements in Water by Direct- Current Argon Plasma Atomic Emission Spectroscopy2D 4191 Test Method for Sodium in Water by AtomicCurrent edition approved March 10, 2002. Published June 2002. Originally published as D 1
16、971 91. Last previous edition D 1971 95.2 Annual Book of ASTM Standards, Vol 11.01.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1Absorption Spectrophotometry2D 1971 02effluents; river and lake waters; and plant and animal tissues.D
17、 4192 Test Method for Potassium in Water by AtomicAbsorption Spectrophotometry2D 4309 Practice for Sample Digestion Using Closed Vessel Microwave Heating Technique for Determination of Total Recoverable Metals in Water2D 4691 Practice for Measuring Elements in Water by FlameAtomic Absorption Spectro
18、photometry2D 5673 Test Method for Elements in Water by InductivelyCoupled Plasma-Mass Spectrometry32.2 U.S. EPA Method:EPA-600/4-79-020 Methods for Chemical Analysis of Wa- ter and Wastes4EPA-600/R-94/111 Methods for the Determination of Met- als in Environmental SamplesSupplement 142.3 U.S. Geologi
19、cal Survey Method:U.S. Geological Survey Open File Report 96225: Methods of Analysis by the U.S. Geological Survey National Water Quality LaboratoryIn-Bottle Acid Digestion of Whole Water Samples5Quality LaboratoryIn-Bottle Acid Digestion of WholeWater Samples53. Terminology3.1 Definitions: For defi
20、nitions of terms used in these practices, refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 digestiontreating a sample with the use of heat or elevated pressures, or both, usually in the presence of chemical additives, to bring analytes of interest into solution or
21、 to remove interfering matrix components, or both.3.2.2 total recoverablethe amount of a metal analyte measurable by atomic absorption spectrophotometry, plasma emission spectroscopy or plasma mass spectrometry after applying the digestion procedure in either Practice A, Practice B, or Practice C. T
22、he 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 requires the measurement of total (suspended and dissolved) metals as well as soluble (dissolved) metals. In such cases, consistent and dependable digesti
23、on procedures must be used so that data derived for the total 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 metals analyses by atomic absorption spectrophotometry or plasma emission spectroscopy (see Test
24、 Methods D 1976, D 3919, D4691, and D 4190) or plasma-mass spectrometry (See Test Method D 5673) and have been shown to give good recovery in the following matrices: industrial effluents; waste water treatment plant influents, sludges, dewatered sludges, andElements which have shown good recovery in
25、clude: 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 unique characteristics. Users must always validate the practice for their particular samples.4.3 The a
26、nalytical results achieved after applying these practices cannot necessarily be deemed as a measure of bioavailable or environmentally available elements.4.4 These three practices may not give the same recovery when applied to the same sample, nor will they necessarily give the same results as achie
27、ved using other digestion techniques. An alternate digestion technique is Practice D 4309.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall be used throughout. Acids shall have a low-metal content or should be doubly distilled and checked for purity. Unless otherwise indicated, it is in
28、tended that all reagents shall conform to the Specifications of the Committee on Analytical Reagents of the American Chemical Society.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the d
29、etermination.5.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming to Specification D 1193, Type I. Other reagent water types may be used, provided it is first ascertained that the water is of sufficiently high purity to permit its us
30、e 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 the analyst from these acids and heated containers. Heated samples and acids may splatter or boil unexpec
31、tedly.7. Sampling7.1 As with all chemical assay procedures, the user of this practice shall ensure that all sample aliquot used are adequately representative of the environmental situation being monitored.7.2 Appropriate sampling and subsampling techniques for particular environmental samples can be
32、 found in other refer- ences.7.3 Collect the sample in accordance with SpecificationD 1192 and Practices D 3370.3 Annual Book of ASTM Standards, Vol 11.02.4 Revised March 1983. Published by the United States Environmental Protection Agency. Available from Superintendent of Documents, U.S. Government
33、 Printing Office, Washington, DC 20402.5 Available from USGS National Center, 12201 Sunrise Valley Dr., Reston, VA20192, USA.6 Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American
34、Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.2D 1971 02PRACTICE ADIGESTION WITH MINERALACIDS AND ELEVATED PRESSURE8. Scope8.1 This
35、practice presents a digestion technique that has broad application and can be performed inexpensively with minimal labor, equipment, and space. In addition, this practice allows for many samples to be processed quickly and simul- taneously under the same conditions.9. Summary of Practice9.1 Samples
36、are placed in loosely capped, heat-, and aci- dresistant containers with selected reagents and subjected to121C and 15 psig (103 kPa gage) for 30 min. After removing any particulate matter remaining, the digestate is ready for analysis by atomic absorption spectrophotometry, plasma emission spectros
37、copy, or plasma-mass spectrometry.9.2 The practice may be found to be more applicable to a particular sample or analytical scheme after appropriate modi- fications of reagent addition, temperature, pressure, digestion time, or container selection. Any such modifications to this practice must be vali
38、dated by the user.10. Apparatus10.1 Digestion Containers50 mL disposable polypropy- lene centrifuge tubes and 125 mL polypropylene reagent bottles with screw caps have been used successfully. Any container that is not attacked by the digestion conditions, is sufficiently free of the analyte(s) of in
39、terest, and can be loosely capped, may be used.10.2 Digestion Container RackAny rack that will fit inside the autoclave, will hold the digestion containers se- curely, and is not attacked by the conditions in the autoclave, may be used.10.3 AutoclaveAny autoclave or similar apparatus with a pressure
40、 chamber large enough to hold the desired number of samples and capable of achieving and holding 121C and 15 psig (103 kPa gage) for 30 min., may be employed. An autoclave with automatic cycling is desirable. As the digesting samples release acidic fumes, the portions of the autoclave coming in cont
41、act with these fumes should be constructed of acid resistant materials.NOTE 1Prolonged use of an autoclave with a stainless steel interior for this practice may result in discoloration of the autoclave walls. This discoloration has not been shown to cause any problems with autoclave operation. A com
42、mercially available autoclave with a stainless steel interior has been in daily 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 inabi
43、lity of the described procedure to quantitatively dissolve the analyte metals of interest in certain situations. These interfer- ences 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 to dissolu
44、tion by the acids. This is most frequently encountered in geological and boiler water samples.11.3 Chemical InterferencesThe complete dissolution ofa metal of interest may not occur due to the digestion conditions being insufficiently rigorous for that particular metal. In other instances, the chemi
45、cal makeup of the sample may render the digestion acids ineffective.12. Reagents12.1 Hydrochloric Acid (sp gr 1.19)Concentrated hydro- chloric 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 described: on
46、e for liquid samples (see 13.2) and one for solid and semi-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 digestion container in the following ratio: 100 volumes sample to 5 volumes HCl (sp gr 1.19) to 1 volume HNO3(sp gr 1.42).13.2.2 Swirl digestion