1、Designation: D 5258 02 (Reapproved 2007)Standard Practice forAcid-Extraction of Elements from Sediments Using ClosedVessel Microwave Heating1This standard is issued under the fixed designation D 5258; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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 This practice covers the digestion of soils and sedimentsfor subsequent determination o
3、f acid-extractable concentra-tions of certain elements by such techniques as atomic absorp-tion and atomic emission spectroscopy.1.1.1 Concentrations of arsenic, cadmium, copper, lead,magnesium, manganese, nickel, and zinc can be extracted fromthe preceding materials. Other elements may be determine
4、dusing this practice.1.2 The analytical sample is arbitrarily defined as that whichpasses a 10-mesh (approximately 2-mm openings) screen andis prepared according to Practice D 3974.1.3 Actual element quantitation can be accomplished byfollowing the various test methods under other appropriateASTM st
5、andards for element(s) of interest.1.4 The detection limit and linear concentration range foreach element is dependent on the atomic absorption or emis-sion spectrophotometric technique employed and may be foundin the manual accompanying the instrument used.1.5 Before selecting a digestion technique
6、, the user shouldconsult the appropriate quantitation standard(s) for any specialanalytical considerations, and Practice D 3974 for any specialpreparatory considerations.1.6 The extent of extraction of elements from soils andsediments by this method is dependent upon the physical andmineralogic char
7、acteristics of the prepared sample.1.7 The values stated in both inch-pound and SI units are tobe regarded separately as the standard. The values given inparentheses are for information only.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
8、is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent Wa
9、terD 3974 Practices for Extraction of Trace Elements fromSediments2.2 Code of Federal Regulations:3CFR Title 21, Part 1030, and Title 47, Part 183. Summary of Practice3.1 The chemical portion of this practice involves aciddigestion to dissociate the elements not interstitially bound insilicate latti
10、ces.3.2 The sample is digested with nitric acid in a closedfluoropolymer vessel using microwave heating to an internalpressure of 100 psi (6.89 3 106dynes/cm2).3.3 This practice provides a sample suitable for analysis byatomic absorption or emission spectrophotometry.4. Significance and Use4.1 Parti
11、al extraction of soils and sediments can provideinformation on the availability of elements to leeching, waterquality changes, or other site conditions.4.2 Rapid heating, in combination with temperatures inexcess of the atmospheric boiling point of nitric acid, reducessample preparation or reaction
12、times.4.3 Little or no acids are lost to boiling or evaporation in theclosed digestion vessel so additional portions of acid may notbe required. Increased blank corrections from trace impuritiesin acid are minimized.5. Interferences5.1 No interferences to the digestion of soils and sedimentsusing mi
13、crowave heating have been observed.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology,and Open-Channel Flow.Current edition approved June 15, 2007. Published July 2007. Originallyapproved in 1992.
14、 Last previous edition approved in 2002 as D 5258 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 to the standards Document Summary page onthe ASTM website.3Availab
15、le from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Precautions should be exercised to
16、avoid those interfer-ences normally associated with the final determination ofelements using atomic absorption or emission spectroscopy.6. Apparatus6.1 Microwave Heating SystemA laboratory microwaveheating system capable of delivering a minimum of 570 W ofmicrowave energy. The system should be capab
17、le of 1 %power adjustments and 1 s time adjustment. The microwavecavity should be fluoropolymer coated and equipped withexhaust ventilation sufficient to provide ten chamber exchangesper minute. The cavity must have a 360 oscillating turntable toensure even sample heating, and be capable of holding
18、diges-tion vessels. Safety interlocks, to shut off magnetron poweroutput, must be contained in the cavity door opening mecha-nism. The system must comply with Department of Health andHuman Services Standards under Code of Federal Regulations,Part 1030.10, Subparts (C) (1), (C) (2), and (C) (3), form
19、icrowave leakage. The system should have Federal Commu-nications Commission (FCC) type approval for operationsunder FCC Rule Part 18.6.2 Digestion VesselsA vessel of 100-mL capacity. Thevessel must be transparent to microwave energy and be capableof withstanding a minimum internal pressure of 120 ps
20、i(8.27 3 106dynes/cm2), and a temperature of 200C. Thevessel must contain a safety pressure relief valve, a rupturedisc, pressure venting system, or be connected to an externalsafety relief valve that will prevent possible vessel rupture orejection of the vessel cap.6.3 Pressure Control VesselA vess
21、el of 100 mL capacity,transparent to microwave energy, with a port for connection toa pressure control device and capable of withstanding aminimum internal pressure of 120 psi and temperature of200C.6.4 Pressure Control DeviceAn externally or internallyoperated device to control the pressure within
22、the digestionvessels. The controller must be capable of 1 psi(6.89 3 104dynes/cm2) adjustments, controlling up to 100 psiand be equipped with an external pressure relief valve if anon-venting control vessel is used.6.5 Filtration ApparatusA gravity filter fitted with What-man No. 414filter paper, or
23、 equivalent.6.6 Volumetric Flask, 100-mL capacity.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the commit-tee on Analytical Reagents of the American Chemical Soci
24、ety,where such specifications are available.5Other grades may beused provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be underst
25、ood to mean reagent water conformingto Type III of Specification D 1193.7.3 Cleaning SolutionMix one volume of technical gradenitric acid (sp gr 1.42) with one volume water.7.4 Nitric Acid (1 + 1)Mix one volume nitric acid (sp gr1.42) with one volume water.8. Hazards8.1 Operate and maintain the micr
26、owave system in accor-dance with the manufacturers recommended safety precau-tions. Do not operate the microwave system in a fume hoodwhere it is surrounded by acid fumes that can cause corrosionof the equipment. Vent acid fumes generated inside the cavityfrom the cavity to a fume hood. Place the di
27、gestion vessels ina fume hood to remove vapors released when a vessel isopened.8.2 Perform the digestion in accordance with the manufac-turers recommended safety precautions.9. Sampling9.1 Collect a sediment sample using an appropriate sam-pling technique.9.2 Prepare the sediment sample in accordanc
28、e with Sec-tions 10 and 12 of Practice D 3974.10. Vessel Cleaning10.1 The manufacturers recommended cleaning proceduremay be followed or the procedure in 10.2 through 10.4 may beused.10.2 Soak the fluoropolymer vessel parts in cleaning solu-tion at 60C for 10 min.10.3 Remove the vessel parts from th
29、e cleaning solution andthoroughly rinse the parts with tap water and then with reagentwater.10.4 Allow the vessel parts to air-dry or wipe dry using aclean, soft cloth.11. Procedure11.1 Determine the power output of the microwave usingthe procedure described in the annex to ensure that the unitmeets
30、 the minimum power requirement.11.2 Obtaina1gportion of the sample prepared in 9.2,weighed to the nearest 0.1 mg, and transfer into digestionvessels. Include an empty digestion vessel in each set as amethod blank.NOTE 1The pressure control vessel must contain1gofsamplematerial.11.3 Add 20 mL of HNO3
31、(1 + 1) to each sample and blankdigestion vessel.11.4 Close each digestion vessel according to the manufac-turers recommended procedures.11.5 Place the closed digestion and pressure control vesselinto the instrument turntable and assemble following themanufacturers suggested procedure.4Whatman No. 4
32、1 filter paper, available from Whatman Specialty Products, 6Just Rd., Fairfield, NJ 07004, has been found suitable for this purpose.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the Amer
33、ican Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D 5258 02 (2007)2NOTE 2The pressure control vessel is connected to the pressurecontr
34、ol device and may be assembled into the turntable differently than thestandard digestion vessels. Refer to the manufacturers suggested proce-dure.11.6 Set the pressure control device to control the digestionvessel pressure at 100 psi (6.89 3 106dynes/cm2).11.7 Heat the vessels to obtain an internal
35、pressure 100 psi(6.89 3 106dynes/cm2) and maintain for 30 min. Refer to themanufacturers suggested procedure.11.8 Allow the vessels to cool to room temperature, andthen vent excess pressure from the vessels. Refer to themanufacturers recommended venting procedure.11.9 Remove the vessels from the tur
36、ntable, place in a fumehood, and open the vessel.11.10 Transfer the contents of the digestion vessel to afiltration device and filter. Wash the vessel and filter thoroughlywith small portions of water. Alternatively, separate the solidand liquid phases by centrifugation.11.11 Transfer the filtered s
37、olution and washes, or centrate,to a 100-mL volumetric flask and dilute to volume with water.12. Precision and Bias12.1 This practice was tested by digesting a single sampleby one laboratory. Table 1 summarizes precision and bias of thetrace element analyses conducted on six portions of NISTRiver Se
38、diment (SRM 1645)6digested by this practice. Alltrace element concentrations were determined by flame orgraphite furnace atomic absorption techniques.13. Keywords13.1 digestion; microwave; sediments; soils; vesselANNEX(Mandatory Information)A1. PROCEDURE TO DETERMINE DELIVERED POWER OF MICROWAVE OVE
39、N AT 100 %INSTRUMENT POWERA1.1 Remove the turntable, drive lug, and all vessels fromthe instrument cavity.A1.2 Adjust the instrument cavity exhaust to minimumairflow.A1.3 Program the instrument for 4 min time and 100 %power.A1.4 Transfer 20006 2 mL of room temperature (19 to25C) water into a 2-L pol
40、ypropylene beaker.A1.5 Measure and record the initial water temperature, Ti,to the nearest 0.1C.A1.6 Place the beaker in the right front corner of theinstrument cavity.A1.7 Heat the water for the programmed time.A1.8 When the heating cycle is complete, immediatelyremove the beaker from the cavity, t
41、horoughly stir the water toensure even heat distribution, and measure the final tempera-ture, Tf, to the nearest 0.1C.A1.9 Calculate the delivered power as follows:P 5 Tf2 Ti! 3 35where:P = delivered power, watts,Tf= final water temperature, C,Ti= initial water temperature, Cand:35 54.2 3 1.0 3 Mtwh
42、ere:4.2 = conversion factor for thermochemical calories towatts,6NIST Standard Reference Materials, Office of Standard Reference Materials,U.S. Department of Commerce, Gaithersburg, MD 20899.TABLE 1 Recovery Data for Six Digestions of NIST River Sediment (SRM 1645)AElement Amount Present (g/g) Amoun
43、t Recovered(g/g)Number of Digestions Standard Deviation Bias (g/g)Arsenic 66 (not cert.) 72 6 4 6Cadmium 10.2 6 1.5 12 6 5 0Copper 109 6 19 121 6 2 12Lead 714 6 28 726 6 8 12Magnesium 7400 6 200 7200 6 70 200Manganese 785 6 97 750 6 10 35Nickel 45.8 6 2.9 49 6 1 3Zinc 1720 6 170 1720 6 10 0ASee Foot
44、note 7 for availability information.D 5258 02 (2007)31.0 = heat capacity of water, calories/g per C,M = mass of water, g, andt = heating time, s.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
45、this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five
46、years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical com
47、mittee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 5258 02 (2007)4
