1、Designation: D 4563 02Standard Test Method forDetermination by Atomic Absorption Spectroscopy ofTitanium Dioxide Content of Pigments Recovered FromWhole Paint1This standard is issued under the fixed designation D 4563; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case 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 atomic absorption (AA)analysis of titaniu
3、m dioxide content in pigments recoveredfrom whole paint. It is applicable to quality control situationswhere the same type of product is repeatedly analyzed.1.2 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this
4、standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. Specific hazard statements are given inSection 7.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 1394 Test Methods for Chemical Analy
5、sis of WhiteTitanium Pigments3E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals4E 288 Specification for Laboratory Glass VolumetricFlasks53. Summary of Test Method3.1 The specimen is prepared for analysis by ashing at450C followed by digesti
6、on with sulfuric acid and ammoniumsulfate as in Test Methods D 1394. The titanium content isdetermined by atomic absorption spectroscopy using a speci-men similar to that previously analyzed by the AluminumReduction Method in Test Methods D 1394.3.2 By utilizing the pigment analyzed in Test MethodsD
7、 1394 as an atomic absorption standard, several hundred TiO2determinations can be made. The AA technique is much fasterthan the technique in Test Methods D 1394 for multipledeterminations and uses only acids. This keeps reagents andtime to a minimum.4. Significance and Use4.1 This test method may be
8、 used in quality control labo-ratories when the repeated analysis of titanium dioxide insimilar paints may be required. Reagents and time are kept toa minimum when this test method is used in place of wetchemical analysis such as in Test Methods D 1394. However,reproducibility and repeatability are
9、not as good as in TestMethods D 1394.5. Apparatus5.1 Atomic Absorption Spectrophotometer, consisting of5.1.1 Atomizer and nitrous oxide burner,5.1.2 Gas-pressure regulator and metering devices for ni-trous oxide and acetylene,5.1.3 Titanium hollow cathode lamp with regulatedconstant-current supply,5
10、.1.4 Monochromator and associated optics,5.1.5 Photosensitive detector connected to an electronicamplifier,5.1.6 Readout device.5.2 Muffle Furnace, capable of maintaining 450 6 25 C.5.3 Circulating Oven, maintained at 105 6 2C.5.4 Porcelain Dishes, 90-mm diameter.5.5 Plastic Disposable Syringe, 10-m
11、L capacity.5.6 Agate Mortar and Pestle, 95-mm outside diameter.5.7 Wide-Mouth Erlenmeyer Flask, 500-mL capacity.5.8 Hot Plate, with variable surface temperature controlfrom 10C above ambient to 370C accurate to within 65C.5.9 Burner.5.10 Volumetric Flask, 1000 mL, plastic (see SpecificationE 288).5.
12、11 Paint Shaker.5.12 Weighing Bottles, wide-mouth, with an external-fittingcap, and no larger than necessary for required amount ofsample.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSub
13、committee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 10, 2002. Published March 2002. Originallypublished as D 4563 - 86. Last previous edition D 4563 - 86 (1996).2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 06.03.4Annual B
14、ook of ASTM Standards, Vol 15.05.5Annual Book of ASTM Standards, Vol 14.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.13 Desiccator.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless oth
15、erwise 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.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficient high pur
16、ity to permit its use without reducing 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 Hydroxide (sp gr 0.90)Concentrated am-monium hydroxide (NH4OH)
17、.6.4 Ammonium Sulfate (NH4)2SO4).6.5 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).6.6 Hydrofluoric Acid (HF)Approximately 49 %.6.7 Standard Pigment Solution.6.7.1 Following the procedure in Section 9 recover thepigment from a paint that is similar to the unknown specimen.Analy
18、ze the extracted pigment for TiO2content in accordancewith theAluminum Reduction Method in Test Methods D 1394and record the percent TiO2found in the pigment.6.7.2 Following the procedure in 12.1-12.5 take a specimenof the pigment extracted in 6.7.1 into solution. Store thissolution for no more than
19、 3 months in a plastic bottle markedwith the percent TiO2as determined in 6.7.1.6.8 Sulfuric Acid (sp gr 1.84), concentrated sulfuric acid(H2SO4).6.9 Toluene.7. Hazards7.1 Concentrated Hydrofluoric Acid Make certain to ob-serve manufacturers recommended precautions for handling.7.2 WarningNitrous ox
20、ide and acetylene can cause ex-plosions, if not used properly. See the suppliers manual ofinstructions for the atomic absorption instrument for properoperation with these gases.8. Calibration and Standardization8.1 Operational instructions for atomic absorption spectro-photometers vary with differen
21、t models. Consult the manufac-turers literature for establishing optimum conditions for thespecific instrument used.8.2 Turn the instrument on and set the wavelength to the365.3-nm titanium line. Apply the recommended current to thetitanium hollow cathode lamp. Allow the instrument to warmup for abo
22、ut 15 min and set the proper slit width.Adjust the gaspressures and ignite the burner in accordance with instructionsfor using nitrous oxide and acetylene.8.3 Aspirate the water to rinse the atomizer chamber from10 to 15 min until the burner head achieves temperatureequilibrium. Set the instrument r
23、eading to zero while doingthis. While aspirating the working standard from 6.7.2 set theinstrument to the percent TiO2(determined in 6.7.1). Reaspi-rate the water and reset the instrument to ZERO. Repeat thisprocedure until the readings become stable.8.3.1 Expanding the scale of a spectrophotometer
24、increasesthe noise level of the readout system. Therefore, if expandingthe scale to make the readout indicate 60 % TiO2has thiseffect, do not use any expansion. For instance, it is notnecessary to make the instrument read 60 for 60 % TiO2standard. It may read 30. If 60 % equals 30, a pigment givinga
25、 reading of 25 would have a TiO2content of 50 %.PIGMENT CONTENT9. Procedure9.1 Mix the samples until homogenous, preferably on amechanical shaker. If air bubbles become entrapped in thesample, stir by hand.9.2 Draw approximately5gofthepaint under test into a10-mL syringe and weigh to 1 mg. Transfer,
26、 by dropwiseaddition, between 2.0 and 4.0 g of the specimen to a taredporcelain dish containing either 2 mL of water (for water-bornepaint) or 2 mL of toluene (for solvent-borne paint). Reweighthe syringe to 1 mg. Swirl the dish during the addition of thepaint and continue to swirl until the specime
27、n is completelydispersed. If a water-borne paint tends to agglomerate or formlumps that cannot be dispersed, a drop or two of concentratedNH4OH may help the dispersement. If the lumps persist,discard the specimen, and prepare a new one. Prepare aduplicate specimen in the same manner.9.3 Dry the spec
28、imens at 110C for 30 min and then driveoff the remaining solvent or water at the lowest temperaturepossible using a Meker burner (under a hood). Do not leave thedishes on the burners after the flames have subsided.9.4 Transfer the dried specimens to a muffle furnace andheat at 450 6 25C for at least
29、 1 h and until no further char isevident. Leave the furnace door slightly open after firstinserting the dishes to allow smoke and possibly flames toescape making certain the furnace is well vented.9.5 Remove the dishes from the muffle furnace, cool in adesiccator, and weigh.9.6 Grind the pigment to
30、pass through an 80-mesh screen.10. Calculation10.1 Calculate the percent pigment content as follows:P 5C 2 W1W23 100 (1)where:P = pigment content, %C = weight of the dish and specimen after ignition, g,W1= weight of the dish alone, g,W2= specimen weight used, g.6Reagent Chemicals, American Chemical
31、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 National Formulary, U.S. Pharmac
32、opeial Convention, Inc. (USPC), Rockville,MD.D456302211. Precision and Bias (see Practice E 180)711.1 In an interlaboratory study of this test method in whichoperators in each of seven laboratories made duplicate analyseson different days and one operator in one laboratory madeduplicate analyses on
33、one day and a single analysis on thesecond day on a water-borne flat wall paint, a solvent-bornesemi-gloss enamel and a solvent-borne house paint containing33, 38.5, and 37 % pigment, respectively, the pooled within-laboratory standard deviation was found to be 0.07 % absolutewith 21 df. The pooled
34、between-laboratories standard deviationwas 0.22 % absolute with 21 df. One laboratorys results forone day were discarded because the duplicates differed signifi-cantly and another laboratorys results for one day because therange differed significantly from all other ranges for Coating 1and a third l
35、aboratorys results for one day because it differedsignificantly from the other days results and those from allother laboratories for Coating 2. Based on these standarddeviations the following criteria should be used for judging theacceptability of results at the 95 % confidence level:11.1.1 Repeatab
36、ilityTwo results, each the mean of dupli-cates, obtained by the same operator should be consideredsuspect if they differ by more than 0.21 % absolute at pigmentcontents of 33 to 39 wt %.11.1.2 ReproducibilityTwo results, each the mean of du-plicates obtained by operators in different laboratories, s
37、houldbe considered suspect if they differ by more than 0.66 %absolute at the same pigment content levels.TITANIUM DIOXIDE CONTENT12. Procedure12.1 Determine the dry weight of two weighing bottles withcaps. In accordance with Table 1 select the appropriatespecimen weight and place the approximate amo
38、unt of recov-ered pigment in each weighing bottle.12.2 Dry the specimens in the open weighing bottles for 2 hat 105C. Cool in a desiccator. After cooling, cap the weighingbottles and weigh as rapidly as possible.12.3 Transfer the dry specimens to 500-mL wide-mouthErlenmeyer flasks. Reweigh bottles a
39、nd caps and recordweights of specimens transferred (W4in equation in 13.1 and13.2).12.4 To the 500-mL flasks, which now contain the speci-mens, add 8 g 6 0.001 g of (NH4)2SO4, 50 mL of concentratedH2SO4and 5 drops of concentrated HNO3. Mix well byswirling the flasks. Heat on a hot plate until dense
40、white fumesare evolved. Continue heating over a hot flame until solutionsare complete (usually requires not more than 5 min of boiling),or until it is apparent that the residues are composed of SiO2orsiliceous matter. Cool and add 100 mL of water with extremecaution.12.5 Quantitatively transfer the
41、contents of the flasks in-cluding any insoluble matter to 1000-mL plastic volumetricflasks (see Specification E 288). Add 50 mL of HCl and 30 mLof HF. Allow to cool to room temperature and then fill to themark with water. Stopper and mix well. Transfer the solutionsto plastic bottles (because of the
42、 HF) and store for no more than3 months for analysis by AA. Solutions must be filteredthrough a Whatman 42 paper before being aspirated.12.6 Calibrate the instrument in accordance with Section 8and aspirate the solutions in the following order:1water (set to ZERO)2working standard (set to percent Ti
43、O2)3specimen (read)1water (set to ZERO)2working standard (set to percent TiO2)3specimen (read)This MUST be repeated until the readings are stable.13. Calculation13.1 Calculate the percent TiO2in the pigment as follows:TiO2,%5C 3 W3W4(2)where:C = reading of specimen (number 3 in 12.6),W3= standard pi
44、gment weight in 6.7.1,g,andW4= specimen pigment weight in 12.3,g.13.2 Calculate the percent TiO2in the whole paint asfollows:TiO2%, 5P 3 W33 AW4(3)where:A = pigment calculated in 10.1, %, andP, W3, and W4= same as in 13.1.14. Precision and Bias (see Practice E 180)714.1 In an interlaboratory study o
45、f this test method in whichoperators in each of eight laboratories analyzed on differentdays a water-borne flat wall paint, a solvent-borne semi-glossenamel and a solvent-borne house paint, respectively contain-ing 28.8, 56.8, and 42.8 weight % titanium dioxide in thepigment, the pooled within-labor
46、atory standard deviation wasfound to be 0.65 % absolute with 22 degrees of freedom. Thepooled between-laboratories standard deviation was 1.31 %absolute with 20 degrees of freedom. One duplicate value fromone laboratory was discarded because the range differedsignificantly from all other duplicate r
47、anges for Coating 1, onedays result from another laboratory because the range differed7Supporting data are available from ASTM International Headquarters. RequestRR: D01-1046.TABLE 1 Specimen Weight RequirementExpected TiO2onpigment, %Specimen Weight,mgA0 to 19 100020 to 29 50030 to 39 33040 to 49 2
48、5050 to 59 20060 to 69 16070 to 79 14080 to 89 13090 to 100 110AEquivalent to about 60 ppm Ti in the final solution.D4563023significantly from all other ranges and both days results froma third laboratory were discarded because the mean differedsignificantly from all other laboratory means for Coati
49、ng 2, andone duplicate value was discarded from the same laboratory aswith Coating 1 because the range differed significantly from allother duplicate ranges for Coating 3. Based on these standarddeviations, the following criteria should be used for judging theacceptability of results at the 95 % confidence level:14.1.1 RepeatabilityTwo results, each the mean of dupli-cates obtained by the same operator, should be consideredsuspect if they differ by more than 1.91 % absolute at TiO2contents of 28 to 57 weight % of the pigment.14.1.2 ReproducibilityTwo re
