1、Designation: D 3717 85a (Reapproved 2005)Standard Test Method forLow Concentrations of Antimony in Paint by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D 3717; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year of last revision. A 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 covers the determination of the contentof antimony in the range between 5
3、0 and 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 qua
4、ntities are made.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.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
5、 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 Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 2832 Guide for Determining Volatile and
6、NonvolatileContent 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 ab
7、sorption 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-reducib
8、le coatings 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 monochroma
9、tor and 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, wate
10、r-cooled, 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 capa
11、city.5.11 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 o
12、n 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 lessening theaccuracy of the determination.1This test method is under the
13、 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. Originallyapproved in 1978. Last pre
14、vious edition approved in 1999 as D 3717 84 (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 onthe ASTM website.3Reagent C
15、hemicals, 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 Pharmacopeiaand Nati
16、onal 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 reagent grade wate
17、rconforming to Type II of Specification D 1193.6.3 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 with water, allo
18、w 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 to the mark wit
19、hconcentrated 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.8. Calibration
20、 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. Dilute to 100 mL
21、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 conditions for
22、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 ignite the burner in
23、 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 a constant val
24、ue, 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.Aspirate water bet
25、ween 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 the high conce
26、ntration 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 linear graph p
27、aper 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 in accordance wi
28、th Guide D 2832.9.2 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 specimen size call
29、ed 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 content.NOTE
30、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 paint draw-dow
31、n 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 the hotplate and
32、 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 and ash at 500C
33、. 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 reflux for 1 h.9.7
34、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 times with water
35、. 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 curve. If the ab
36、sorbance 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 analysisusing a larger s
37、pecimen size.NOTE 5Increased sensitivity may be obtained with instruments pos-sessing scale expansion and concentration readout capability.D 3717 85a (2005)2NOTE 6The method of standard additions may be used to improve theaccuracy of the analysis. This method is particularly recommended for usewith
38、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 manufacturer.10. Ca
39、lculation10.1 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 diluted to/volume
40、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 Bias412.1 The p
41、recision 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-laboratory coeff
42、icient 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 % confidence
43、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, obtained by operator
44、s 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 International
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48、t the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4Supporting data are available from ASTM International Headquarters. RequestRR: D01-1011.D 3717 85a (2005)3
