1、Designation: C872 10 (Reapproved 2015)Standard Test Method forLead and Cadmium Release from Porcelain EnamelSurfaces1This standard is issued under the fixed designation C872; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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.INTRODUCTIONThis test method covers the precise determination of lead or cadmium extracted by acetic acid fromporcelain enamel
3、 surfaces. The procedure of extraction may be expected to accelerate the release oflead or cadmium and to serve, therefore, as a severe test that is unlikely to be matched under actualconditions of usage.1. Scope1.1 This test method covers the precise determination oflead and cadmium extracted by ac
4、etic acid from porcelainenamel surfaces.1.2 Values stated in SI units are to be regarded as thestandard. Inch-pound units are given for information only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of th
5、is standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C738 Test Method for Lead and Cadmium Extracted fromGlazed Ceramic SurfacesD1193 Specification for Reagent Water3. Summ
6、ary of Test Method3.1 The lead and cadmium extracted from the article undertest by acetic acid at 20 to 24C (68 to 75F) after 24 h ofleaching are measured by atomic absorption spectrophotometryusing a specific hollow cathode lamp for lead and cadmiumrespectively.4. Significance and Use4.1 The determ
7、ination of lead and cadmium release fromporcelain enamel surfaces was formerly of interest only tomanufacturers of porcelain enamel cookware and similar foodservice products. Food contact surfaces of these container-typeproducts have been evaluated using a test procedure similar toTest Method C738.
8、Recently, however, there has been a need tomeasure lead and cadmium release from flat or curved porce-lain enamel surfaces that are not capable of being evaluated bya test similar to Test Method C738.5. Interferences5.1 Since a specific hollow cathode lamp for lead andcadmium is used, there are no i
9、nterferences.6. Apparatus6.1 Atomic Absorption Spectrophotometer , equipped with a102-mm (4-in.) single slot or Boling burner head and digitalconcentration readout attachment (DCR) if available.3Thisinstrument should have a sensitivity of about 0.5 mg/L of leadfor 1 % absorption and a sensitivity of
10、 about 0.03 mg/L ofcadmium for 1 % absorption. The operating conditions asspecified in the instrument manufacturers analytical methodsmanual shall be used.NOTE 1ppm, mg/L, and g/mL are equivalent units.6.2 Hollow Cathode Lead Lamp, with wavelength set at283.3 or 217.0 nm.6.3 Hollow Cathode Cadmium L
11、amp, with wavelength setat 228.8 nm.6.4 Glassware of chemically resistant borosilicate glass, tomake reagents and solutions.1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 onMaterials for Porce
12、lain Enamel and Ceramic-Metal Systems.Current edition approved May 1, 2015. Published June 2015. Originallyapproved in 1977. Last previous edition approved in 2010 as C872 10. DOI:10.1520/C0872-10R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servic
13、e at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Perkin-Elmer model 303 and Jarrell-Ash model 82-546 have been foundsuitable for this determination.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
14、700, West Conshohocken, PA 19428-2959. United States16.5 Test Cell, suitable for the containment of the leachingsolution on a flat porcelain enamel surface. A cell that hasproved suitable for this purpose is shown in Fig. 1.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all
15、 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 Society,where such specifications are available.4Other grades may beused provided it is first ascertained that the reagent is ofsu
16、fficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water (seeSpecification D1193).7.3 Acetic Acid (4 % by volume)Mix 1 volume of glacialacetic acid with 24
17、 volumes of water.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United
18、 States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.Metric Equivalents for ApparatusDimensions (Fig. 1)in. mm18 3.214 6.438 9.5114 31.812532 45.2214 57.22.31 58.72.5 63.54 101.64116 103.2418 104.8512 139.7FIG. 1 Suitable Test CellC872 10 (2015)2NOTE
19、2A reagent blank shall be run each time a 4 % acid solution isprepared.7.4 Detergent RinseAdd 15 g of suitable alkaline deter-gent5to 1 gal (3.79 L) of lukewarm tap water.7.5 Lead Nitrate Solution (1000 mg Pb/L)Dissolve 1.598g of lead nitrate (Pb(NO3)2) in 4 % acetic acid and dilute to 1L with 4 % a
20、cetic acid. Commercially available standard leadsolutions may also be used.7.6 Hydrochloric Acid (1 % by weight)Mix 1 volume ofconcentrated hydrochloric acid (HCl sp gr 1.19) with 37volumes of water.7.7 Cadmium (1000 mg Cd/L)Dissolve 0.500 g of cad-mium metal in 250 mL of hot 1 % HCl (see 7.6), cool
21、, anddilute to 500 mL with 1 % HCl. Commercially availablestandard cadmium solutions may also be used.8. Samples8.1 Test SpecimensSpecimens may be cut from productionparts or may be prepared on metal blanks under productionconditions. Tests may be made on finished parts where flathorizontal surfaces
22、 are available.8.2 SizeThe size of the test area shall be approximately 26cm2(4 in.2).9. Procedure9.1 Preparation of SampleTake, at random, three identicalunits and cleanse each with the detergent rinse. Then rinse withtap water followed by distilled water. Dry the specimens and fitinto a suitable t
23、est cell similar to that shown in Fig. 1, or placea weighted cell onto a flat surface of a production part. Filleach unit with 4 % acetic acid, with a maximum of 40 mL foreach 6.45 cm2(1 in.2) of exposed surface. Record the volumeof acid for each unit in the sample. Cover each unit with clear,colorl
24、ess glass plate to prevent evaporation of the solution,avoiding contact between the cover and surface of the leachingsolution, and expose to normal laboratory light for 8 to 10 hduring the leaching period. Let the solution stand for 24 h atroom temperature (20 to 24C (68 to 75F).9.2 Preparation of S
25、tandards:9.2.1 Lead StandardsDilute lead nitrate solution (see 7.5)with acetic acid (see 7.3) to obtain working standards havingfinal concentrations of 0, 5, 10, 15, and 20 mg Pb/L.9.2.2 Cadmium StandardsDilute cadmium stock solution(see 7.7) with acetic acid (see 7.3) to obtain working standardshav
26、ing final concentrations of 0.0, 0.3, 0.5, 1, 1.5, and 2.0 gCd/mL.9.3 Determination of Lead by Atomic AbsorptionStir thesample (leaching) solution and pour off a portion into a cleanflask. Using the atomic absorption spectrophotometer (6.1) andhollow cathode lamp (6.2), concomitantly determine the a
27、b-sorbance of the lead working standards (9.2.1) and sample(leaching) solutions, diluting the latter with 4 % acetic acid ifrequired (if solution contains over 20 mg/L). Concentratesamples containing less than 1 ppm lead by accurately trans-ferring a minimum of 50.0 mL of solution to a 250-mL beaker
28、and evaporating to dryness on a steam bath. Dissolve theresidue in 4 % acetic acid by adding exactly 0.1 volume ofsolution taken for concentration, cover with a watch glass, andswirl to complete dissolution. Prepare a standard curve ofabsorbance versus concentration (mg/L). Determine the leadcontent
29、 (mg Pb/L) of sample (leaching) solution from thestandard curve.NOTE 3If a digital concentration readout is used, the standard curveis not necessary. However, standards bracketing the solution under testshould be used.9.4 Determination of Cadmium by Atomic AbsorptionSpectrophotometryProceed as in 9.
30、3 using the cadmiumhollow-cathode lamp (see 6.3) and cadmium standards (see9.2.2). If the sample (leaching) solutions contain more than 2mg Cd/L, dilute with 4 % acetic acid. Concentrate samplescontaining less than 0.1 mg/L as in 9.3.10. Report10.1 Report the type of units tested, the volume of acid
31、used, and the lead and cadmium, respectively, leached inmicrograms per millilitre for each unit tested.NOTE 4As indicated in Section 1, this procedure covers the extractionand measurement of lead and cadmium. It is general in that it does notrecommend specific sample unit types. For special end uses
32、, as forexample, process control or interlaboratory testing, a specific size and typeof sample unit should be used.11. Precision and Bias11.1 Precision of the analytical method for a single ormultiple operator within a single laboratory is within thesensitivity of the atomic absorption spectrophotom
33、eter.11.2 The precision and bias between laboratories is depen-dent upon the ability to obtain representative samples of thestatistical universe being sampled.5Asuitable detergent is Calgonite, manufactured by the Calgon Corp., Box 1436,Pittsburgh, PA 15230, and is available in most supermarkets.C87
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