1、Designation: D 3618 05Standard Test Method forDetection of Lead in Paint and Dried Paint Films1This standard is issued under the fixed designation D 3618; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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 test method is intended as a screening test todetermine if the solids in a paint contain more than 0.5 % lead.The test described
3、 barely detects the presence of 0.4 % butgives a definite positive result at the 0.5 % level.NOTE 1This test method may be used to detect the presence of leadat concentrations higher or lower than 0.5 % by making appropriatechanges in the specimen size and reagent quantities specified.1.2 The values
4、 stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 Paints giving an unexpected positive or questionableresult should be analyzed quantitatively for lead, using TestMethod D 3335.1.4 This standard does not purport to address all of thesa
5、fety 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 applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7.2. Referenced Documents
6、2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 2832 Guide for Determining Volatile and NonvolatileContent of Paint and Related CoatingsD 3335 Test Method for Low Concentrations of Lead,Cadmium, and Cobalt in Paint by Atomic AbsorptionSpectroscopy3. Summary of Test Method3.1 The sample o
7、f liquid paint or dried film is prepared bydry ashing a weighed specimen at 475 to 500C. The ash isextracted with hot sodium hydroxide solution and a drop of theextract is transferred to filter paper. Lead present is oxidized tolead peroxide with bromine water, then treated with “tetrabase”to produc
8、e a blue quinoidal salt. Known amounts of lead areadded to standard paints that are concurrently tested to providea base for comparison.4. Significance and Use4.1 The permissible level of heavy metals in certain coat-ings is specified by governmental regulatory agencies. This testmethod provides a f
9、ully documented procedure for determininglow concentrations of lead present in both water and solvent-reducible coatings to determine compliance.5. Apparatus5.1 Burner, Meker-type.5.2 Crucibles, porcelain, high-form, 15-mL, with covers.5.3 Filter Paper, ashless, medium texture.5.4 Hot Plate, with va
10、riable surface temperature controlover the range from 70 to 200C.5.5 Muffle Furnace, maintained at 475 6 25C.5.6 Syringe, glass, 2-mL.5.7 Volumetric Flasks, 50, 100, 1000-mL.5.8 Paint Shaker.5.9 Paint Draw-Down Bar.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests un
11、less otherwise specified. Unless otherwiseindicated, it is intended that all reagents shall conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable.3Other grades may be used, provided it is firstascertained that the
12、 reagent is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent grade waterconforming to Type II of Specification D 1193.6.3 Acetic Acid, glacial.1This
13、test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published February 2005. Originallyap
14、proved in 1977. Last previous edition approved in 1999 as D 3618 85a (1999).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 onth
15、e ASTM website.3Reagent 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 St
16、ates Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Ammonium Hydroxide (1 + 1)Mix 1 volume of con-centrated ammonium hydroxide (NH4OH,
17、sp gr 0.90) with 1volume of water.6.5 Bromine Water, saturated.6.6 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).6.7 Lead Standard Stock Solution, Aqueous (1 mg/mL)Dissolve 1.600 g of lead nitrate (Pb(NO3)2) in 100 mL ofwater, add 2 mL of nitric acid (sp gr 1.42), and dilute to 1 L.6.8 Lead
18、 Standard Working Solution, Aqueous (0.2 mg/mL)Pipet 10 mL of the aqueous lead standard stock solutioninto a 50-mL volumetric flask and dilute to volume with water.6.9 Toluene, technical grade.6.10 Lead Standard Stock Solution, Solvent-Based (1 mg/mL)Dissolve 4.2 g of lead naphthenate (containing 24
19、 %lead) in 100 mL of toluene and dilute to 1 L.NOTE 2Other toluene-soluble lead driers such as lead tallate, leadlinoleate, and lead octoate may also be used provided that the lead contentis accurately known and the appropriate weight is diluted to 100 mL toprovide a toluene solution containing 1 mg
20、/mL of lead.6.11 Lead Standard Working Solution, Solvent-Based (0.2mg/mL)Pipet 10 mL of the solvent-based standard stocksolution into a 50-mL volumetric flask and dilute to volumewith toluene.6.12 Sodium Hydroxide Solution (12 % w/v)Carefullydissolve 12 g of sodium hydroxide in 100 mL of water.6.13
21、Paint, Standard Solvent-Reducible, any solvent-reducible paint known to contain less than 100 ppm of lead.6.14 Paint, Standard Water-Reducible, any water-reduciblepaint known to contain less than 100 ppm of lead.6.15 Tetrabase Reagent (4,48-Methylenebis (N,N-dimethylaniline), 1 % in 10 % Acetic Acid
22、Dissolve1goftetrabase4in 50 mL of water to which 10 mL of glacial aceticacid has been added. Dilute to 100 mL with water.7. Hazards7.1 Glacial acetic and concentrated nitric acids will causeburns of the skin and eyes. Sodium hydroxide is corrosive. Usecare in handling these materials.Avoid contact w
23、ith skin. Referto suppliers Material Safety Data Sheets. Bromine watershould be prepared and used in a laboratory hood.57.2 Use only a rubber bulb aspirator for pipetting liquids.8. Procedure8.1 If the sample is a liquid coating, mix it until homoge-neous, preferably on a mechanical shaker. Determin
24、e thenonvolatile content in accordance with Guide D 2832.NOTE 3Recover dried paint films from previously coated substrates(being careful not to remove any underlying material from the substrate)or prepare in the laboratory from liquid samples. For the laboratorypreparation, flow some of the well-mix
25、ed sample onto a clean glass plate.The use of a paint draw-down bar is recommended to obtain a uniformfilm thickness not exceeding 2 mils (50 m). Allow to dry in an oven at105C for a minimum of 1 h. Scrape the dried film off the glass plate,preferably with a single edge razor blade.8.2 Weigh to 0.1
26、mg, 50 mg of paint solids into a porcelaincrucible or 50-mL glass beaker. For a liquid coating, determinethe specimen weight to be taken by the following equation:S 55C(1)where:S = specimen weight, g, andC = nonvolatile content, %NOTE 4Crucibles or beakers used in this test method should be newor in
27、 very good condition. Otherwise, it is possible that some lead may belost and a false negative obtained.8.3 Weigh 50 mg of solids from the appropriate standardpaint (solvent-reducible or water-reducible) into each of twoadditional porcelain crucibles or 50-mL glass beakers. Using a2-mL glass syringe
28、, add 1.0 mL of the appropriate 200-ppmstandard working solution (solvent-reducible or water-reducible) to one of the crucibles or beakers, and 1.8 mL to theother.NOTE 5The standard paint to which has been added 1.0 mL ofstandard working solution contains approximately 0.4 % lead based on thepaint s
29、olids, and the one to which has been added 1.8 mL of standardworking solution will contain approximately 0.72 % lead based on thepaint solids.8.4 Place all three crucibles or beakers on a cold hot plateand slowly increase the temperature until the material is dried.With some types of coatings, an in
30、itial oven-drying at 105Cmay be necessary to remove solvents without incurring lossesdue to spattering.8.5 When the specimens appear to be dry, or when startingwith a dried film, gradually increase the temperature of the hotplate until the material chars.8.6 After charring is complete, place the cru
31、cibles or bea-kers in a preheated muffle furnace and ash at 475 to 500C.8.7 When the ashing appears to be complete, (approxi-mately 1 to 2 h) remove the crucibles or beakers from themuffle furnace and allow them to cool to room temperature.Add5mLof3 N sodium hydroxide solution to each crucibleor bea
32、ker and mix thoroughly with a stirring rod. Scrape anyadhering residue from the sides or bottom of the container andbreak up any particles, using a separate stirring rod for eachspecimen.8.8 Place covers on the crucibles or watch glasses on thebeakers, and boil gently for approximately 5 min. Remove
33、from the hot plate and allow the contents to settle. Do not filter.8.9 With the tip of the stirring rod, transfer 1 to 2 drops ofeach extract to the center of a piece of filter paper. Usingseparate droppers, successively apply directly on each speci-men spot a drop of bromine water and a drop of NH4
34、OHsolution. Remove excess ammonia by holding each filter paperover a hot plate until no odor is detectable, but do not take tocomplete dryness. Place 2 drops of tetrabase reagent on eachspot and compare the color developed on the specimen spotwith those on the standard paint spots. To ensure that ma
35、ximumcolor development has been achieved, add 1 or 2 more drops of4The sole source of supply of tetrabase, Eastman-244, known to the committeeat this time is Eastman Organic Chemicals, Rochester, NY 14650. If you are awareof alternative suppliers, please provide this information to ASTM Internationa
36、lHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5Saturated bromine water may be purchased from chemical supply houses.D3618052tetrabase reagent on the center of each spot after the firstaddition has almost-dried
37、 (if still wet, the color may diffuse).NOTE 6Although the color is stable, it is barely visible in the rangefrom 0.4 to 0.5 %. Comparing results with those obtained on the twostandard paints helps to orient the observer to the color intensity to beexpected.NOTE 7Certain iron-based pigments have high
38、 natural manganeselevels. The ash extract of products containing high manganese mayproduce a diffuse blue ring on the filter paper. With experience, this iseasily distinguished from the small blue spot produced by lead.9. Report9.1 Report a positive test (lead content equal to or in excessof 0.5 % o
39、f paint solids) when a blue color forms and persistsfor several seconds.10. Precision and Bias610.1 An interlaboratory test was conducted in which ana-lysts from eight laboratories tested water and solvent-basedcoatings having lead contents slightly lower and slightly higherthan 0.5 % based on the s
40、olids. All analysts made correctjudgments for greater than 0.5 % lead (positive) and less than0.5 % lead (negative), with only one analyst reporting a singleresult as “questionable.”10.2 BiasBias cannot be determined for this methodbecause there are no accepted standards for lead in paint anddried p
41、aint films.11. Keywords11.1 lead; lead in paints and dry paint films; spat test forleadASTM 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
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