1、Designation: D3717 85a (Reapproved 2010)Standard Test Method forLow Concentrations of Antimony in Paint by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D3717; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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.1. Scope1.1 This test method covers the determination of the contentof antimony in the range between 50 a
3、nd 200 ppm (mg/kg)present in the solids of liquid coatings or in dried filmsobtained from previously coated substrates. There is no reasonto believe that higher levels could not be determined by thistest method, provided that appropriate dilutions and adjust-ments in specimen size and reagent quanti
4、ties are made.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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 this standard to
5、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 Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2832 Guide for Determining Volatile and Nonvol
6、atileContent of Paint and Related Coatings3. Summary of Test Method3.1 The sample of liquid coating or dried film is preparedfor analysis by dry ashing at 500C, followed by refluxing withhydrochloric acid and stannous chloride. The antimony contentof the acid extract is determined by atomic absorpti
7、on spec-troscopy.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 fully documented procedure for determininglow concentrations of antimony present in both water- andsolvent-reducible coa
8、tings to determine compliance.5. Apparatus5.1 Atomic Absorption Spectrophotometer, consisting of anatomizer and either a single- or three-slot burner; gas pressureregulating and metering devices for air and acetylene; anantimony source lamp with a regulated constant current supply;a monochromator an
9、d associated optics; a photosensitivedetector connected to an electronic amplifier; and a readoutdevice.5.2 Muffle Furnace, maintained at 500 6 10C.5.3 Oven, maintained at 105 6 2C.5.4 Hot-Plate, with variable surface temperature controlover the range from 70 to 200C.5.5 Reflux Condenser, water-cool
10、ed, and fitted with astandard-taper joint.5.6 Erlenmeyer Flask, 125-mL, with standard-taper joint tofit condenser.5.7 Volumetric Flasks, 100 and 1000-mL.5.8 Dropping Bottles, 8 or 15-mL (14 or12-oz) capacity.5.9 Glass or Disposable Syringes, 10-mL capacity.5.10 Pipets, 1, 5, 10, and 15-mL capacity.5
11、.11 Filter Paper, ashless, medium or slow filtering.5.12 Paint Shaker.5.13 Paint Draw-Down Bar.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Anal
12、ytical 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 lessening theaccuracy of the determination.1This test method is under the juris
13、diction 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 June 1, 2010. Published June 2010. Originallyapproved in 1978. Last previous edit
14、ion approved in 2005 as D3717 85a (2005).DOI: 10.1520/D3717-85AR10.2For 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 onthe ASTM we
15、bsite.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 States Phar
16、macopeiaand 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.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean re
17、agent grade waterconforming to Type II of Specification D1193.6.3 Antimony Standard Stock Solution (0.1 mg/mL)Dissolve 0.1000 g of antimony metal in 40 mL of sulfuric acid(H2SO4, sp gr 1.84) by heating. Cool, carefully transferquantitatively to a 1-L volumetric flask already approximatelyhalf full w
18、ith water, allow to cool to room temperature, anddilute to 1 L.6.4 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).6.5 Stannous Chloride Solution (400 g/L in HCl)Dissolve40 g of tin (II) chloride (SnCl2) in 50 mL of HCl (sp gr 1.19).Transfer to a 100-mL volumetric flask and fill
19、to the mark withconcentrated HCl.7. Hazards7.1 Use care in handling concentrated HCl because it iscorrosive and may cause burns to the skin and eyes and itsvapor is irritating to mucous membranes. Refer to suppliersMaterial Safety Data Sheet.7.2 Use only a rubber bulb aspirator for pipetting liquids
20、.8. Calibration and Standardization8.1 Prepare 100-mL quantities of at least four standardsolutions bracketing the expected antimony concentration inthe sample to be tested. To suitable aliquots of the 0.1 mg/mLstandard antimony solution, add 40 mL of concentrated HCland 8 drops of SnCl2solution. Di
21、lute to 100 mL with water.Prepare a blank solution by diluting 40 mL of concentratedHCl and 8 drops of SnCl2solution to 100 mL with water.8.2 Operational instructions for atomic absorption spectro-photometers vary with different models. Consult the manufac-turers literature for establishing optimum
22、conditions for thespecific instrument used.8.3 Turn the instrument on and set the wavelength to the217.6-nm antimony line. Apply the recommended current tothe antimony source lamp. Allow the instrument to warm upfor about 15 min and set the slit width. Adjust the air andacetylene pressures and ignit
23、e the burner in accordance withinstructions.8.4 Aspirate water to rinse the atomizer chamber. Aspirate astandard solution and make any necessary readjustment ininstrument parameters to obtain maximum absorption.8.5 Aspirate the blank solution. When the recorder, meter,or other readout device reaches
24、 a constant value, it should beimmediately zeroed. Repeat this blank determination until asteady, repeatable zero value is obtained at the maximumresponse.8.6 Aspirate each of the appropriate standard solutions inascending antimony concentrations and record the correspond-ing instrument readings.Asp
25、irate water between each standard.NOTE 1A deuterium background corrector, if available, should beused to correct for background absorption. If not available, it is necessaryto reaspirate each standard solution and measure the background at anearby nonabsorbing region of the spectrum.NOTE 2Because of
26、 the high concentration and corrosive nature of theacids used for the analysis, it is essential that the burner assembly bedisassembled and thoroughly cleaned out immediately after the analysesare completed. Consult the instrument manual for cleaning instructions.8.7 Construct a calibration curve on
27、 linear graph paper byplotting the absorbance (corrected for background) versusconcentration (micrograms per millilitre) for each standardsolution.9. Procedure9.1 If the sample is a liquid coating, mix it until homoge-neous, preferably on a mechanical paint shaker. Determine thenonvolatile content i
28、n accordance with Guide D2832.9.2 Prepare at least two replicate samples by weighing bydifference from a dropping bottle or syringe, 5 to 10 g of themixed liquid coating, or by directly weighing approximately 2to6gofdried film, into 125-mL Erlenmeyer flasks. Weigh tothe nearest 0.1 mg.NOTE 3The spec
29、imen size called for will have a concentration ofapproximately 4 to 12 g/mL antimony in the final diluted solution forpaints containing approximately 200 ppm (mg/kg) antimony based on thenonvolatile content, and 1 to 3 g/mL for paints containing approximately50 ppm antimony, based on the nonvolatile
30、 content.NOTE 4Recover 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-mixed sample onto a clean glass plate.The use of a
31、paint draw-down bar is recommended to obtain a uniformfilm thickness not exceeding 2 mils (50 m). Allow the film to dry in anoven at 105C for a minimum of 1 h. Scrape the dried film off the glassplate, preferably with a single-edge razor blade.9.3 Place the flasks containing the liquid coating on th
32、e hotplate and slowly increase the temperature until the material isdried.9.4 When the sample appears to be dry, or when startingwith a dried film, gradually increase the temperature of the hotplate until the material chars.9.5 After charring appears complete, place the flasks in themuffle furnace a
33、nd ash at 500C. When the ashing appears tobe complete (approximately 1 to 2 h), remove the flasks fromthe muffle furnace and allow to cool to room temperature.9.6 Carefully add 40 mL of concentrated HCl and 8 drops ofSnCl2solution to each flask. Connect the flasks to water-cooledcondensers and reflu
34、x for 1 h.9.7 Filter each digested specimen through medium-porosityfilter paper into a 100-mL volumetric flask. If the filtrate is notclear, refilter through fine-porosity filter paper. Rinse each flaskseveral times with water, adding the rinsings to the filter paper.Wash the filter paper several ti
35、mes with water. Adjust thevolume to 100 mL with water and mix.9.8 Aspirate each test solution and determine the absor-bance in the same manner in which the instrument wascalibrated (see Note 1 and Note 2). Determine the concentra-tion of antimony in micrograms per millilitre from the calibra-tion cu
36、rve. If the absorbance is above the range covered by thecalibration curve, dilute an aliquot of the test solution to asuitable volume with water containing 40 mL of HCl and 8drops of SnCl2solution per 100 mL. If the absorbance is belowthe range covered by the calibration curve, repeat the analysisus
37、ing a larger specimen size.NOTE 5Increased sensitivity may be obtained with instruments pos-sessing scale expansion and concentration readout capability.D3717 85a (2010)2NOTE 6The method of standard additions may be used to improve theaccuracy of the analysis. This method is particularly recommended
38、 for usewith unknown samples where matrix effects may be potentially signifi-cant. For a detailed description of the procedure and calculations used inthe method of standard additions, consult a standard text on atomicabsorption spectroscopy or the instruction manual provided by theinstrument manufa
39、cturer.10. Calculation10.1 Calculate the mean concentration of antimony in thenonvolatile portion of the sample as follows:Antimony, ppm mg/kg! in nonvolatile 5 C 3 F 3 104!/NV 3 S!(1)where:C = concentration of antimony in the aspirated test solu-tion, g/mL,F = dilution factor from 9.8 (volume dilut
40、ed to/volume ofaliquot),NV = percent nonvolatile of paint sample (use 100 ifsample was dried film), andS = grams of sample.11. Report11.1 Report the antimony content of the nonvolatile contentof the sample and whether the analysis was conducted on aliquid coating or a dried film.12. Precision and Bi
41、as412.1 The precision estimates are based on an inter-laboratory study in which eight different laboratories analyzedin duplicate, on two different days, three samples of water-reducible paints and three samples of solvent-reducible paintscontaining from 50 to 200 ppm (mg/kg) antimony. Thewithin-lab
42、oratory coefficient of variation was found to be4.8 % relative at 31 degrees of freedom and the between-laboratory coefficient of variation was 8.8 % relative at 25degrees of freedom. Based on these coefficients, the followingcriteria should be used for judging the acceptability of resultsat the 95
43、% confidence level:12.1.1 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 than14 % relative.12.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtaine
44、d by operators in different labo-ratories, should be considered suspect if they differ by morethan 26 % relative.12.2 BiasThe mean of duplicate determinations withinany laboratory should be within 18 % relative of true value.13. Keywords13.1 AAS, antimony; low concentration of antimony inpaintsASTM
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