1、Designation: E1645 01 (Reapproved 2016)1Standard Practice forPreparation of Dried Paint Samples by Hotplate orMicrowave Digestion for Subsequent Lead Analysis1This standard is issued under the fixed designation E1645; the number immediately following the designation indicates the year oforiginal ado
2、ption 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.1NOTECaution statements in 6.1.2, 6.1.2.1, 6.1.2.2, 6.2.4.4, 7.2.1, and 7.2.2 were
3、changed to Warning statementseditorially in January 2016.1. Scope1.1 This practice covers the sample preparation proceduresfor paint samples that are collected during the assessment,management or control of lead hazards.1.2 This practice describes the digestion procedures using ahot plate or microwa
4、ve oven or apparatus for paint samples thatare to be analyzed for lead content.1.3 This practice covers the general considerations forquantitative sample extraction for total recoverable lead indried paint samples (either bulk paint or paint powder) usinghot plate or microwave heating techniques, or
5、 both.1.4 This practice contains notes that are explanatory and notpart of the mandatory requirements of the standard.1.5 This practice is based on two NIOSH Methods, 7082and 7105, and on an EPA standard operating procedure for leadin paint.1.6 The values stated in SI units are to be regarded asstan
6、dard. No other units of measurement are included in thisstandard.1.7 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 health practices and determine the appl
7、ica-bility of regulatory limitations prior to use. For specificprecautionary statements, see 6.1.2, 6.1.2.1, 6.1.2.2, 6.2.4.4,7.2.1, and 7.2.2.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterE1605 Terminology Relating to Lead in Buil
8、dingsE1729 Practice for Field Collection of Dried Paint Samplesfor Subsequent Lead Determination (Withdrawn 2014)32.2 Other Documents:Environmental Protection Agency, Standard Operating Pro-cedures for Lead in Paint by Hotplate- or Microwave-based Acid Digestions and Atomic Absorption or Induc-tivel
9、y Coupled Plasma Emission Spectrometry ; U.S. EPA,Research Triangle Park, NC (1991).4(NTIS No.PB92114172)NIOSH Manual of Analytical Methods, P.M. Eller and M.E.Cassinelli, Eds., 4th ed., Methods 7082 and 7105; Na-tional Institute for Occupational Safety http:/www.cdc.gov/niosh.Copyright ASTM Interna
10、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 digestionthe sample preparation process that solubi-lizes (extracts) targeted analytes present in the sample, andresults in an acidified aqueous solution called the digestate.3.1.4 extractionthe dissolu
11、tion of target analytes from asolid matrix into a liquid form. During sample digestion, targetanalytes are extracted (solubilized) into an acid solution.3.1.5 method blanka sample, devoid of analyte, that isanalyzed to determine its contribution to the total blank(background) reading.3.1.6 non-spike
12、d samplea sample, devoid of analyte, thatis targeted for addition of analyte but is not fortified with alltarget analytes prior to sample preparation.3.1.6.1 DiscussionAnalysis results for this sample areused to correct for background levels in the blank medium thatis used for spiked and spiked dupl
13、icate samples.3.1.7 reagent blanka digestate that reflects the maximumtreatment given any one sample within a batch of samples,except that it has no sample placed initially into the digestionvessel. (The same reagents and processing conditions that areapplied to field samples within a batch are also
14、 applied to thereagent blank.)3.1.7.1 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.3.1.8 reference material (certified reference material)(CRM)a
15、 material of known composition where the lead levelis certified by the manufacturer.3.1.9 sample seta group of samples (one or more).3.1.10 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
16、.10.1 DiscussionAnalysis results for these samples areused to provide information on the precision and accuracy ofthe overall process.4. Summary of Practice4.1 Lead in dried paint samples (chips, powder, etc.) issolubilized (extracted) by digestion with nitric acid and hydro-gen peroxide facilitated
17、 by heat, or by a mixture of nitric acidand hydrochloric acid facilitated by microwave energy. (It isassumed that the paint samples were collected in accordancewith Practice E1729; however, this practice can be used for anycollected paint sample.) The lead content of the digestedsample is then in a
18、form ready for measurement.5. Significance and Use5.1 Paint in buildings and related structures needs to bemonitored for lead content in order to determine the potentiallead hazard. Hence, effective and efficient methods are requiredfor the preparation of paint samples that may contain lead.5.2 This
19、 practice may be used for the digestion of paintsamples that are collected during various lead-hazard controland risk assessment activities associated with lead abatement inand around buildings and related structures. This practice isalso suitable for the digestion of paint samples collected fromloc
20、ations such as commercial buildings.5.3 This practice may be used to prepare samples that havebeen obtained in order to ensure compliance with laws thatgovern lead content in paints.5.4 This practice may be used to prepare samples that havebeen collected for risk assessment purposes.5.5 This practic
21、e is intended for use with paint samples thatare prepared for subsequent analysis by laboratory-basedquantitative analytical methods.6. Apparatus6.1 Heating Equipment:6.1.1 Electric Hot Platesuitable for operation at surfacetemperatures up to at least 140C. A temperature of at least100C, as measured
22、 by a thermometer placed inside a boro-silicate glass container (on the hot plate) filled with digestionsolution, should be attainable. (See Note 1.)NOTE 1Provided that the hot plate is capable of handling the extraheating required, use of a 12 to 25-mm (approximately 0.5 to 1-in.) thickaluminum pla
23、te placed on the burner head can help reduce the presence ofhot spots common to electric hot plates.6.1.2 Microwave Extraction Apparatus:WarningEnsure that manufacturers safety recommenda-tions are followed.NOTE 2The procedure described is for microwave digestion systemswith a temperature control sy
24、stem. Microwave digestion systems that areequipped only with a pressure control system or lower pressure vessels, orboth, may be used, provided that a prior assessment of the dissolutionefficiency is carried out.6.1.2.1 Microwave Digestion Systemdesigned for closedvessel digestion, with power output
25、 regulation, fitted with atemperature control system capable of sensing the temperatureto within 62C, and automatically adjusting the microwavepower output within 2 s. The microwave cavity shall beresistant to chemical attack, and equipped with exhaust venti-lation for acid vapor protection of the u
26、nit and operator. Allelectronics shall be protected against corrosion to ensure safeoperation. Safety interlocks, to shut off magnetron poweroutput, shall be contained within the oven door openingmechanism.WarningDomestic (kitchen) microwave ovens shall notbe used, since there are very significant h
27、azards associated withtheir use for the procedure described in this standard. Forexample, acid vapors released into the cavity can corrodesafety devices that prevent the magnetron from shutting offwhen the door is opened, potentially exposing the operator tomicrowave energy.Also, the fumes generated
28、 can be extremelyhazardous.NOTE 3Apressure control system is also very useful, since it providesa safeguard against the possibility of sample loss due to excessive pressurebuildup and partial venting of the sample vessels.6.1.2.2 Lined Sample Vesselsclosed, designed for carryingout microwave digesti
29、ons, capable of withstanding a tempera-ture of at least 180C and with an internal volume of at least 50mL. The vessels must be transparent to microwave energy, andvessel liners shall be chemically inert. The vessels must beE1645 01 (2016)12capable of withstanding high internal pressures (up to at le
30、ast3000 kPa) and temperatures (up to at least 180C). Vesselsshall also be equipped with a safety relief valve or disc that willprevent vessel rupture or ejection of the vessel cap. Suchvessels consist of an inner liner and cover made of a micro-wave transparent and chemically resistant material (usu
31、ally afluorocarbon polymer such as tetra-fluoromethoxil polymer(TFM), which contains and isolates the sample solution from ahigh strength, outer pressure structure. Other types of samplevessels designed to operate at equivalent or higher tempera-tures or pressures, or both, may be used.WarningFor cl
32、osed vessel designs, the material fromwhich the outer vessels are made is usually not as chemicallyinert as the liner material. Since the outer vessels provide thestrength required to withstand the high pressures within theinner liners, they must be inspected regularly to check for anychemical or ph
33、ysical degradation.6.2 Reagents, Glassware and Supplies:6.2.1 Apparatus-Hot Plate Digestion:6.2.1.1 Borosilicate glass beakers, 125-mL or 50-mL withwatchglass covers,6.2.1.2 Class A borosilicate volumetric flasks, 100mL and200mL,6.2.1.3 Class A borosilicate volumetric pipets, volume asneeded,6.2.1.4
34、 Linear polyethylene bottles with caps, 100mL,6.2.1.5 Analytical balance, accurate to 60.1 mg,6.2.1.6 Glass funnels,6.2.1.7 Filter paper, and6.2.1.8 Weighing Paper or Weighing Boat.6.2.2 Apparatus-Microwave Digestion:6.2.2.1 Centrifuge, with 30 mL polysulfone centrifuge tubesand polypropylene screw
35、closure,6.2.2.2 Class A volumetric and graduated pipets,6.2.2.3 Mechanical shaker, and6.2.2.4 Analytical balance, accurate to 60.1 mg.6.2.3 Reagents-Hot Plate Digestion:6.2.3.1 Concentrated nitric acid, ACS reagent grade orspectrographic grade 16.0 M HNO3,6.2.3.2 Nitric acid, 10 % (w/v): Add 100 mL
36、concentratedHNO3to 500 mL ASTM Type I water (see SpecificationD1193). Dilute to 1 L with ASTM Type I water,6.2.3.3 Hydrogen peroxide, 30 % H2O2(w/w); ACS reagentgrade, and6.2.3.4 ASTM Type I water (see Specification D1193).6.2.4 Reagents-Microwave Digestion:6.2.4.1 Concentrated nitric acid, ACS reag
37、ent grade orspectrographic grade 16.0 M HNO3,6.2.4.2 Concentrated hydrochloric acid, ACS reagent grade12.3 M HCl,6.2.4.3 ASTM Type I water (see Specification D1193), and6.2.4.4 Extraction SolutionIn a 1-Lvolumetric flask, com-bine the following in order and mix well: 500 mLASTM TypeI water, 60 mL co
38、ncentrated HNO3and 180 mL concentratedHCl. Cool to room temperature and dilute to 1 L with ASTMType I water. (WarningNitric and hydrochloric acid fumesare toxic. Prepare in a well-ventilated fume hood.)7. Sample Treatment7.1 Sample Preparation:7.1.1 Sample Mass and AreaAfter analysis, report thefina
39、l results in area concentration (mg Pb/cm2) or massconcentration (ppm Pb, percent Pb by mass, or alternativeunits). If area concentration is desired, sample areas must beprovided (by the person submitting the samples) for each paintsample (chip, powder, etc.). The total mass of area concentra-tion s
40、amples must be determined. Samples may be subsampled(after grinding and homogenization), depending on the samplemass.7.1.2 Area SamplesFor each field sample, homogenize thedried paint sample (inside the original sample container, ifpossible) as described in the following:7.1.2.1 Don a new clean pair
41、 of vinyl gloves to performsample handling.7.1.2.2 Remove any large amounts of substrate present inthe sample. Exercise care when removing substrate to avoidany losses of paint. If required, use a clean safety razor bladeor equivalent tool to aid in substrate removal.7.1.2.3 Determination of Total C
42、ollected Sample MassAccurate determination of the collected sample mass is re-quired to report lead analysis results in terms of area concen-tration (mass per unit area of paint sample). A completetransfer of the sample is required to whatever preweighedcontainer is used to hold the sample during ma
43、ss determination(for example, weighing boat or weighing paper). Total massshall be made to the nearest 0.1 mg.The following precautions shall be observed during deter-mination of total mass:(1) Total sample mass can be determined either before orafter sample homogenization. Determination of total sa
44、mplemass is generally advisable prior to homogenization whensamples consist of large intact chips that can be easilytransferred without incurring losses. Determination of totalsample mass is generally advisable after homogenization whensamples can be homogenized in the original sample collectioncont
45、ainer and the samples are not large intact chips.NOTE 4In this case, the sample container should be weighed afterhomogenization.(2) Any visible traces of paint left in the original containeror container used for homogenization (if different from originalcontainer) may result in bias of the final lea
46、d analysis results.Therefore, such traces shall be minimized.Any visible materialthat cannot be transferred shall be documented in samplepreparation records.(3) For sample transfers following homogenization, mostlosses caused by the presence of fine powder remaining in theoriginal container or conta
47、iner used for homogenization (ifdifferent from original container) will not result in any signifi-cant bias (particularly with respect to the large samplingvariability that normally accompanies the field collectionpractice.)(4) For sample transfers prior to homogenization (that is,when homogenizatio
48、n cannot be performed in the originalcontainer used in sample collection), any losses caused by finepowder remaining in the original container may result in asignificant bias. Therefore, sample transfers conducted prior toE1645 01 (2016)13sample homogenization shall be performed with extra attention
49、to avoiding visible traces of paint left in the original container.NOTE 5If sample mass is determined after homogenization in thecollection container, the container should be weighed (clean) either beforesampling, or after sample homogenization, reweighing (immediatelyfollowing sample transfer), and recleaning.7.1.2.4 Homogenization of SamplesSamples shall be ho-mogenized as finely as possible, regardless of whether areaconcentration or mass concentration results are desired. Thehomogenization of the sample serves two purposes: (a) toensure
