1、Designation: D 2374 05Standard Test Method forLead in Paint Driers by EDTA Method1This standard is issued under the fixed designation D 2374; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a titrimetric determination oflead in liquid paint driers that can be dissolved in glacial aceticacid and utilizes the dis
3、odium salt of ethylenediaminetetraace-tic acid dihydrate (EDTA).1.2 This test method is not applicable to drier blends. Ifdriers other than cobalt are present, they may interfere byreacting with EDTA under the conditions used for analysis.1.3 All cations that can be titrated with EDTA in alkalinemed
4、ia interfere and must not be present in the sample.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
5、ility 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.2. Referenced Documents2.1 ASTM Standards:2D 600 Specification for Liquid Paint DriersD 1193 Specification for Reagent WaterE 180 Practice
6、for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial ChemicalsE 300 Practice for Sampling Industrial Chemicals3. Summary of Test Method3.1 The liquid drier is dissolved in glacial acetic acid,diluted with isopropyl alcohol and water, and treated with anexcess of standa
7、rd EDTA solution. The excess is titrated withstandard cupric sulfate solution using PAN as the metalindicator.4. Significance and Use4.1 The amount of lead drier used in oxidizing-type coatingssignificantly affects their drying properties. This test methodmay be used to confirm the stated lead conte
8、nt of pure liquidlead drier soluble in glacial acetic acid and manufactured foruse by the coatings industry.5. Apparatus5.1 Centrifuge, capable of developing 1000 to 2000 g.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended
9、thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without l
10、essening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type II of Specification D 1193.6.3 Ammonium Chloride (NH4Cl).6.4 Ammonium Hydroxide (sp gr 0.90)Concentrated am-monium hydroxide (NH4OH)
11、.6.5 Buffer Solution (pH 10.0)Dissolve 67.5 g of NH4Cl inwater, add 570 mL of concentrated NH4OH (sp gr 0.90), anddilute to 1 L.6.6 Cupric Sulfate, Standard Solution (0.05 M)Dissolve12.5 g of cupric sulfate pentahydrate (CuSO45H2O) in waterand dilute to 1 L.6.7 Eriochrome Black-T IndicatorTriturate
12、0.20 g of theconcentrated dye with 100 g of NaCl and store in a tightlystoppered jar. This mixture remains stable for several years.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommitt
13、ee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published February 2005. Originallyapproved in 1965. Last previous approved in 1999 as edition D 2374 85 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cus
14、tomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents no
15、tlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、 West Conshohocken, PA 19428-2959, United States.6.8 EDTA, Standard Solution (0.05 M)Dissolve 18.62 gof EDTA in water and dilute to 1 L. Store in a polyethylene orborosilicate glass bottle.6.9 Glacial Acetic Acid (sp gr 1.06).6.10 Isopropyl Alcohol (99.5 %).6.11 Methyl Red IndicatorDissolve 0.2 g of
17、 methyl red in100 mL of methanol, ethanol, or isopropanol.6.12 PAN Indicator (1(2-Pyridylazo)-2-Naphthol)Preparea dilute solution of the indicator by dissolving 0.10 g in 100mL of ethanol or isopropanol.6.13 Sodium Acetate SolutionPrepare a saturated aqueoussolution of sodium acetate (NaC2H3O2) in w
18、ater.6.14 Sodium Chloride (NaCl).6.15 Sodium Hydroxide Solution (80 g/L)Dissolve 80 g ofsodium hydroxide (NaOH) in water and dilute to 1 L.6.16 Sulfuric Acid (5+1)Carefully mix 8 volumes ofconcentrated sulfuric acid (H2SO4, sp gr 1.84) with 1 volumeof water.6.17 Zinc Oxide (ZnO).7. Sampling7.1 Take
19、a small sample of liquid drier from bulk using theprocedures in Practice E 300 appropriate for the size of thecontainer: section on Bottle Sampling for tanks and tank cars,or section on Tube Sampling for drums and cans.NOTE 1Liquid driers are normally homogeneous so that only simplephysical tests, s
20、uch as specific gravity or solids content, on top and bottomsamples from tanks are required to confirm that separation has notoccurred.Agitate drums in accordance with the section on Tube Samplingof Practice E 300.7.2 Examine the sample of drier for sediment or suspendedmatter which if present is ev
21、idence of noncompliance withSpecification D 600.7.3 If the sample is homogeneous keep it in a stopperedvessel to prevent solvent evaporation prior to analysis.8. Standardization8.1 Weigh to the nearest 0.1 mg approximately 1.5 g of ZnOinto a 100-mLbeaker and add 10 mLof H2SO4(8 + 1). Transferthe sol
22、ution to a 500-mL volumetric flask and dilute to themark with water. Pipet a 50-mL aliquot into a 500-mLErlenmeyer flask, add 100 mL of distilled water, 2 or 3 dropsof methyl red solution, and neutralize with NaOH solution (80g/L).Add 5 mLof buffer solution, 0.2 g of Eriochrome Black-Tindicator, and
23、 titrate with EDTA until the color changes fromred to blue, where the last red shade just disappears.8.1.1 Calculate the molarity, M1, of the EDTA solution asfollows:M15WV13 0.0814!(1)where:W = ZnO used, g,V1= EDTA solution, mL, and0.0814 = molecular weight of ZnO 3 103= millimolar weight of ZnO.8.2
24、 CuSO4, Standard Solution (0.05 M)Determine thetiter of the CuSO4solution by titrating 50 mL of the standardEDTA solution with CuSO4as described in 9.4 using the PANindicator.8.2.1 Calculate the molarity, M2, of the CuSO4solution asfollows:M25M13 V2!V3(2)where:M1= molarity of EDTA solution,V2= EDTA
25、solution, mL, andV3= CuSO4solution, mL.9. Procedure9.1 Check the clarity of the drier. If not clear, centrifuge aportion of the sample until it is clear. Keep the centrifuge tubestoppered so that solvent will not evaporate.9.2 Weigh the following specimen amounts into a 500-mLErlenmeyer flask and ad
26、d 5 mL of glacial acetic acid: (1) for24 % lead, 1.0 to 1.5 g, (2) for 30 and 32 % lead, 0.7 to 0.9 gand (3) for more or less lead use proportionate specimen sizes.Warm on a hot plate at low heat, swirling the flask until thespecimen is completely dissolved.9.3 In a second flask (blank) put the same
27、 amount of glacialacetic acid but no specimen.Add 200 mL of isopropyl alcohol,100 mL of water, 6 mL of concentrated NH4OH, 10 mL ofNa2C2H3O2, and 50 mL of EDTA solution to each flask. Swirlto ensure complete mixing and warm both flasks at steam bathtemperature for 5 min.9.4 To each of the flasks add
28、 2 mL of PAN indicator andtitrate with the standard CuSO4solution to a blue end point.NOTE 2Because of the color of metal indicators (and some of theircomplexes) being affected by pH changes, the pH must be kept constantduring titration by the recommended buffer during titration.10. Calculation10.1
29、Calculate the percent of lead, A, present as follows:A 5FB 2 V4! 3 M23 FSG3 100 (3)where:B = CuSO4solution required for titration of the blank,mL,V4= CuSO4solution required for the specimen, mL,M2= molarity of CuSO4solution,F = millimolecular weight of the metal in the sample= 0.2072 for lead, andS
30、= specimen used, g.11. Precision and Bias (see Practice E 180)11.1 Precision:11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays should be considered suspect if they differ by more than0.10 % lead.11.1.2 ReproducibilityTwo resul
31、ts, each the mean of du-plicate determinations, obtained by operators in different labo-ratories, should be considered suspect if they differ by morethan 0.50 % lead.D237405211.2 BiasBias cannot be determined for this methodbecause there are no accepted standards for lead in paint driers.12. Keyword
32、s12.1 drier analysis; EDTA method; leadASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the
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