1、Designation: E1726 16Standard Practice forPreparation of Soil Samples by Hotplate Digestion forSubsequent Lead Analysis1This standard is issued under the fixed designation E1726; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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. Scope1.1 This practice covers drying, homogenization, and aciddigestion of soil samples and associated quality control
3、(QC)samples using a hot plate type method for the determination oflead using laboratory atomic spectrometry analysis techniquessuch as Inductively Coupled Plasma Atomic Emission Spec-trometry (ICP-AES), Flame Atomic Absorption Spectrometry(FAAS), and Graphite Furnace Atomic Absorption Spectrom-etry
4、(GFAAS).1.2 This practice is based on U.S. EPA SW 846, TestMethod 3050.1.3 This practice contains notes that are explanatory and arenot part of the mandatory requirements of this standard.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematica
5、lconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and
6、 health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterE288 Specification for Laboratory Glass Volumetric FlasksE1605 Terminology Relating to Lead in
7、Buildings2.2 U.S. Government Analytical Method:3U.S. EPA SW 846 Test Methods for Evaluating Solid WastePhysical/Chemical Methods2.3 ISO Standards:4ISO Guide 30 Terms and Definitions Used in Connectionwith Reference MaterialsISO 1042 Laboratory glasswareOne-mark volumetricflasksISO 8655 Piston-operat
8、ed volumetric apparatus - Part 1:Terminology, general requirements and user recommen-dations3. Terminology3.1 Definitions: For definitions of terms relating to thepreparation of dried paint samples that are not given here, referto Terminology D1129 or Terminology E1605.3.1.1 batcha group of field or
9、 quality control samples thatare processed together using the same reagents and equipment.3.1.2 digestatethe acidified aqueous solution that resultsfrom digestion of the sample.3.1.3 digestionhigh temperature sample preparation pro-cess that involves chemical breakdown to solubilize targetedanalytes
10、 present in a sample, to result in an acidified aqueoussolution called the digestate.3.1.4 method blanka sample, devoid of analyte, that isanalyzyed to determine its contribution to the total blank(background) reading.3.1.5 non-spiked samplea sample, devoid of analyte, thatis targeted for addition o
11、f analyte but is not fortified with alltarget analytes prior to sample preparation.3.1.5.1 DiscussionAnalysis results for this sample areused to correct for background levels in the blank medium thatis used for spiked and spiked duplicate samples.3.1.6 reagent blanka digestate that reflects the maxi
12、mumtreatment given any one sample within a batch of samples,except that it has no sample placed initially into the digestion1This practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.23 on LeadHazards Associated wi
13、th Buildings.Current edition approved Oct. 1, 2016. Published November 2016. Originallyapproved in 1995. Last previous edition approved in 2009 as E1726 01(2009).DOI: 10.1520/E1726-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm
14、.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Publishing Office, 732 N. Capitol St., NW,Washington, DC 20401-0001, http:/www.gpo.gov.4Available from American National Standards Institute (ANS
15、I), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1vessel. (The same reagents and processing conditions that areapplied to field samples within a batch are also applied
16、 to thereagent blank.)3.1.6.1 DiscussionAnalysis results from this sample pro-vide information on the level of potential contaminationresulting from only laboratory sources that are experienced bysamples processed within the batch.3.1.7 reference material (certified reference material)(CRM)reference
17、 material accompanied by a certificate, oneor more of whose property values are certified by a procedurewhich establishes its traceability to an accurate realization ofthe unit in which the property values are expressed; eachcertified value is accomplished by an uncertainty at a statedlevel of confi
18、dence (ISO Guide 30).3.1.8 spiked sample or spiked duplicate samplea blankmedium that contains no purposely added analyte to which aknown amount of analyte is added before preparation.3.1.8.1 DiscussionAnalysis results for these samples areused to provide information on the precision and accuracy of
19、the overall process.4. Summary of Practice4.1 A representative soil sample is dried and homogenized,and then digested (in a batch mode with other samples) on a hotplate using nitric acid and hydrogen peroxide. The digestate isdiluted for final volume prior to lead measurement.5. Significance and Use
20、5.1 There is a need to monitor the lead content in andaround buildings and related structures in order to determinethe potential lead hazard. Hence, effective and efficient meth-ods are required for the preparation of soil samples fordetermination of their lead content.5.2 This practice may be used
21、for the digestion of soilsamples that are collected during various construction andrenovation activities associated with lead abatement in andaround buildings and related structures. The practice is alsosuitable for the digestion of soil samples for lead analysescollected from other locations, such
22、as near roads and steelstructures.5.3 This practice is intended to be used to prepare samplesthat have been collected for hazard assessment purposes.5.4 This practice is not capable of determining lead boundwithin matrices, such as silica, that are not soluble in nitricacid.5.5 This practice include
23、s drying and homogenization stepsin order to help assure that reported lead results are represen-tative of the sample and are independent of potential differ-ences in soil moisture levels among different sampling loca-tions or changing weather conditions.6. Apparatus6.1 Equipment:6.1.1 Analytical Ba
24、lance, capable of accurately determiningthe mass to the nearest 0.001 g.6.1.2 Drying Oven, capable of maintaining a temperature of100 to 120C.6.1.3 Electric Hot Plate, capable of maintaining a tempera-ture of 80 to 100C as measured with a thermometer placedinto a beaker or flask filled with water si
25、tting on the hot platehead. When required to reduce the presence of hot spots in theelectrical hot plate, placea2to2.5cm(0.75 to 1 in.) thickaluminum plate on the burner head.6.1.4 Grinding ApparatusMortar and pestle (porcelain oragate), shatter box, or mixer mill.6.1.5 Micropipettors with Disposabl
26、e Plastic Tips conform-ing to ISO 8655, sizes needed to make reagent additions, andspiking standards (see Note 1).NOTE 1In general, the following sizes should be readily available: 1to 5 mL adjustable, 1000, 500, 250, and 100 L.6.1.6 Sieves, 4.75 mm (U.S. Standard No. 4), 2 mm (No.10), and 500 m (No
27、. 35), plastic or stainless steel (see Note 2).When sieves containing soldered joints are used, then all solderjoints shall be coated with epoxy resin prior to use to protectsamples from potential lead contamination originating in thesolder. Visually inspect prior to use for the presence of baremeta
28、l.NOTE 2Plastic or stainless steel sieves are better for use instead ofbrass sieves to alleviate possible lead contamination of the soil samplesfrom contact with lead solder common to brass sieves.6.1.7 Thermometers, red alcohol, that cover a range from 0to 110C.6.2 Glassware and Supplies:6.2.1 Boro
29、silicate GlasswareVolumetric flasks with stop-pers meeting Specification E288 or conforming to ISO 1042,100 mL; Griffin beakers, 100, 150 or 250 mL; watch glassessized to cover Griffin beakers.6.2.2 Plastic Gloves, powderless.6.2.3 Air-Tight Sample Containers1 L (1 qt) or 4 L (1 gal)re-sealable plas
30、tic bags, or plastic 50 mL centrifuge tubes.6.2.4 Volumetric Flasksmeeting Specification E288 orconforming to ISO 1042, 100 mL and other sizes as needed tomake dilutions of sample digests or lead standards used forfortification of spiked samples.6.2.5 Tongs, metal.6.2.6 Spoon, stainless steel.7. Rea
31、gents7.1 Purity of ReagentsReagent grade chemicals shall beused in this practice. Unless otherwise indicated, all reagentsshall conform to the specifications for the Committee onAnalytical Reagents of the American Chemical Society, wheresuch specifications are available.5Other grades shall not beuse
32、d unless it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lesseningaccuracy of the determination.7.2 Nitric AcidConcentrated, suitable for atomic spec-trometry analysis, such as spectroscopic grade.5Reagent Chemicals, American Chemical Society Specific
33、ations, AmericanChemical Society, Washington, DC, www.chemistry.org. For suggestions on thetesting of reagents not listed by the American Chemical Society, see the UnitedStates Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention,Inc. (USP), Rockville, MD, http:/www.usp.org.E1726 1627.
34、3 Hydrogen Peroxide, 30 % (w/w), suitable for atomicspectrometry analysis such as spectroscopic grade.7.4 Acetone, reagent, spectroscopic grade.7.5 WaterUnless otherwise indicated, references to watershall mean reagent water as defined by Type I of SpecificationD1193. (ASTM Type I Water: minimum res
35、istance of 16.7megohmcm, or equivalent.)7.6 Calibration Stock Solution, 100 g/mL of lead (Pb)CRM in dilute (typically 2 %) nitric acid.8. Sample Preparation Procedure8.1 Sample Pre-Treatment:8.1.1 Treat each sample in a processing batch equally.8.1.2 If possible before removal, break up the soil sam
36、plewithin the original containers containing the samples (see Note3).NOTE 3This will not be possible for wet soil samples.8.1.3 Label an acid-cleaned 100, 150, or 250 mL Griffinbeaker (or other vessel suitable for oven drying of soils thatwill not contaminate the sample with lead) with a hightempera
37、ture wax pen or any other marker that will be visibleafter exposure to the drying oven.8.1.4 Transfer the entire soil sample to the labeled Griffinbeaker. Cover with a watch glass (tip to one side to permitmoisture removal), and place in a drying oven for a minimumof6hatatemperature of 110 6 10C. Sa
38、mples that cake orplug the sieve require additional drying (see Note 4).NOTE 4Soil samples should not cake or exhibit packing characteristicof moisture, but should flow freely through the sieve (see 8.1.7) whenbroken apart.8.1.5 If the received soil sample is excessively large, thenany attempts to s
39、ub-sample prior to drying and sieving arelikely to cause bias. If possible, use a larger beaker to containthe entire sample. If not, then use multiple beakers followed byre-combining after drying. Samples that cake or plug the sieverequire additional drying (see Note 4).8.1.6 Using tongs, remove the
40、 beakers containing thesamples and allow them to cool to room temperature.8.1.7 Don a pair of plastic gloves and push the soil samplethrough a clean 4.75 mm sieve (U.S. Standard No. 4) to removeany large objects or root material, or both. Discard materialretained on the sieve (see Notes 5 and 6). Cl
41、ean the sievebetween samples by tapping or using forced air or other drymethod to prevent cross-contamination. Perform this step in alocation well removed from other samples in process and in anarea where soil dust will not contaminate the laboratoryoperations such as in front of a fume hood.NOTE 5I
42、f the samples do not appear to contain any large objects orroot material, it is not necessary to perform this step with the 4.75 mmsieve.NOTE 6In order to minimize small particle size soil losses, this stepshould not be performed inside a fume hood.8.1.8 Don a pair of plastic gloves and push the soi
43、l samplethrough a clean 2 mm sieve (U.S. Standard No. 10) to removecoarse material (see Note 6). Discard material retained on thesieve. Clean the sieve between samples by tapping or usingforced air or other dry method to prevent cross-contamination.Perform this step in a location well removed from o
44、thersamples in process, and in an area where soil dust will notcontaminate the laboratory operations, such as in front of afume hood.8.1.9 Grind the sample using a porcelain mortar and pestleor other appropriate homogenization apparatus such as ashatter-box or mixer mill. Clean the grinding apparatu
45、s be-tween samples to prevent cross-contamination betweensamples by rinsing with water and drying. When any materialis retained from 8.1.10, delay cleaning until this retainedmaterial for the sample is re-ground as described in 8.1.11.Anacetone rinse will facilitate drying (see Note 7).NOTE 7Acetone
46、 should not be used on sieves since it can damageepoxy coatings which may be present to seal lead solder joints.8.1.10 Place the ground up sample on a clean 500 m sieve(U.S. Standard No. 35). Use a stainless steel spoon to helpmove material around until no more sample will pass throughthe sieve. Do
47、not discard the retained material (see Note 8).Return any retained material for one more grinding as de-scribed in 8.1.9.NOTE 8A second re-grinding step is included for retained material toavoid inadvertent loss of larger pieces of material that can remain as aresult of inadequate grinding.8.1.11 Pl
48、ace the ground up retained sample material back onthe clean U.S. Standard No. 35 (500 m sieve) (see Note 6).Using a stainless steel spoon, help move material around untilno more sample will pass through the sieve, adding the passedmaterial to the previous sample material that passed throughthe sieve
49、. Discard any retained material. Clean the sievebetween samples by tapping or using forced air or other drymethod to prevent cross-contamination. Perform this step in alocation well removed from the samples in process.8.1.12 Label acid-cleaned 100, 150, or 250 mL Griffinbeakers and watch glasses for performing the digestion of eachsoil sample and associated QC samples.8.1.13 Transfer sieved portion to a labeled Griffin beakerand place in a drying oven overnight or for a minimum of 12 h,or to constant mass at a temperature of 110 6 10C (see N
