1、Designation: D3804 02 (Reapproved 2014)Standard Test Method forIron in Paint Driers by EDTA Method1This standard is issued under the fixed designation D3804; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. 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 titrimetric determination ofiron in liquid iron driers soluble in isopropyl alcohol andutilizes the dis
3、odium salt of ethylenediaminetetraacetic aciddihydrate (EDTA).1.2 This test method is limited to the determination of theiron content of a liquid drier that does not contain other drierelements. This method is not applicable to drier blends.1.3 The values stated in SI units are to be regarded asstan
4、dard. No other units of measurement are included in thisstandard.1.4 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 establish appro-priate safety and health practices and determine the appl
5、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D600 Specification for Liquid Paint DriersD1193 Specification for Reagent WaterE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals (With
6、drawn 2009)3E300 Practice for Sampling Industrial Chemicals3. Summary of Test Method3.1 The liquid iron drier is diluted with isopropyl alcoholand the iron chelated with excess standard EDTA. The solutionis buffered and the excess EDTA is titrated with standard zincchloride solution to the Eriochrom
7、e Black T end point.4. Significance and Use4.1 This test method may be used to confirm the statedcontent of a liquid iron drier soluble in isopropyl alcohol andmanufactured for use in the coatings industry. The contentdetermines activity level.5. Interferences5.1 All cations that can be titrated wit
8、h EDTA in alkalinemedia interfere and must not be present in the sample or mustbe masked.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 Analytical
9、 Reagents of the American Chemical Society,where such specifications are available.4Other 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.6.2 Purity of WaterUnless otherwise indica
10、ted, referencesto water shall be understood to mean reagent water conformingto Type II of Specification D1193.6.3 Ammonium Hydroxide (1+3)Add 10 mL of concen-trated ammonium hydroxide (NH4OH, sp gr 0.90) to 30 mLwater.6.4 Buffer SolutionAdd 350 mL of concentrated ammo-nium hydroxide (NH4OH) to 54 g
11、of ammonium chloride(NH4Cl) and dilute to 1 L with water.6.5 EDTA, Standard Solution (0.01 M)Weigh to 10 mgabout 3.73 g of the disodium salt of ethylenediaminetetraaceticacid dihydrate (EDTA), dissolve in water, and dilute toapproximately 1 L in a polyethylene or borosilicate glassbottle.6.6 Hydroch
12、loric Acid (1+3)Add 3 mL of concentratedhydrochloric acid (HCl, sp gr 1.19) to 9 mL of water.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paint
13、s and Paint Materials.Current edition approved July 1, 2014. Published July 2014. Originally approvedin 1979. Last previous edition approved in 2008 as D3804 02 (2008). DOI:10.1520/D3804-02R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
14、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Socie
15、ty, 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. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.C
16、opyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.7 Eriochrome Black-T IndicatorTitrate 0.20 g of theconcentrated dye with 100 g of NaCl and store in a tightlystoppered jar. This mixture remains stable for several years.6.8 Isopropyl A
17、lcohol (99.5 %).6.9 Zinc Chloride, Standard Solution (0.01 M)Weigh to0.5 mg about 0.65 g of zinc (Note 1) onto a glazed paper.Transfer to a 1-L volumetric flask and add 25 mL of dilute HCl(7+18) (add 7 mL of concentrated acid (sp gr 1.19) to 18 mLof water). Warm if necessary on a steam bath to disso
18、lvecompletely. Cool, dilute to the mark with water and mixthoroughly. Calculate the exact molarity of this approximately0.01-M solution as follows:M25 W/65.4 (1)where:M2= molarity of ZnCl2solution, andW = zinc used, g.65.4 = atomic weight of zinc.NOTE 1Zinc ribbon cut into small pieces with clean sc
19、issors ispreferred. Granular (20 mesh) zinc requires several hours of heating on asteam bath for complete solution. Store the zinc ribbon in a tightly sealedcontainer to prevent the surface of the zinc from oxidizing.7. Sampling7.1 Take a small sample of liquid drier from bulk using theprocedures in
20、 Practice E300 appropriate for the size ofcontainer, tanks and tank cars or drums and cans.NOTE 2Liquid driers are normally homogeneous so that only simplephysical tests, such as specific gravity or solids content, on top and bottomsamples from tanks are required to confirm that separation has notoc
21、curred. Agitate drums in accordance with Practice E300.7.2 Examine the sample of drier for sediment or suspendedmatter which if present is evidence of noncompliance withSpecification D600.7.3 If the sample is homogeneous keep it in a stopperedvessel to prevent solvent evaporation prior to analysis.8
22、. Standardization8.1 EDTA, Standard Solution (0.01 M)Transfer 40.0 mLof this solution from a buret into a 250-mL assay beaker orwide-mouthed flask.Add 50 mLof isopropyl alcohol, 10 mLofbuffer solution, and 0.2 g of indicator (6.7). Mix thoroughly byswirling. Titrate with standard ZnCl2solution (6.9)
23、 to the firstpermanent tinge of red. Calculate the exact molarity of thisapproximately 0.01 M solution as follows:M15 V2M2/V1(2)where:M1= molarity of EDTA solution,V2= ZnCl2solution, mL,M2= molarity of ZnCl2solution, andV1= EDTA solution, mL.9. Procedure9.1 Check the clarity of the drier. If not cle
24、ar, centrifuge aportion of the sample until it is clear, keeping the centrifugetube stoppered to prevent solvent evaporation.9.2 Place a few grams of the drier in a 50-mL Erlenmeyerflask fitted with a cork through which passes a dropping tubeand rubber bulb (or medicine dropper) and obtain the total
25、weight. Weigh by difference to 0.5 mg, 0.18 to 0.22-g speci-mens (8 to 12 drops), into 400-mL beakers. This specimen sizeis for driers of 6 % iron content; adjust the size according toexpected percent iron to contain about 0.2 mM of iron. Add100 mL of isopropyl alcohol and 3 mL 1 + 3 HCl to eachspec
26、imen and swirl to mix.Add a few boiling aids and heat thesolution just to boiling on a hot plate; remove and cool to roomtemperature in a water bath.9.3 From a buret measure 40.0 mL of standard EDTAsolution into each beaker. Neutralize with dilute NH4OH(1 + 3), as indicated by a change in the color
27、of the solutionfrom yellow to reddish. Add 10 mL of the buffer solution and0.3 g of the Eriochrome Black-T indicator mixture. Thisaddition should result in a blue-colored solution. Immediatelyback-titrate the excess EDTA with the standard ZnCl2solution(Note 3) to the first permanent tinge of red (No
28、te 4). Theback-titration must be completed within 2 min (Note 5 andNote 6).NOTE 3During the titration stir the solution manually or by means ofa magnetic stirrer.NOTE 4To some observers, this color change appears as a change topurple. However, the transition is sharp and, with a little practice, eas
29、ilynoted.NOTE 5The time used in the titration step with ZnCl2solution affectsthe results. A titration time of less than 2 min gives consistently goodresults. Longer times give higher results.NOTE 6If the end point is overstepped, add 1.0 mL of the EDTAsolution to the mixture and titrate again with s
30、tandard ZnCl2solution. Usetotal volume of each solution for the calculation.10. Calculation10.1 Calculate the percent of iron present as follows:Iron, % 5 V3M12 V4M2! 5.59/S (3)where:V3= EDTA solution, mL,M1= molarity of EDTA solution,V4= ZnCl2solution, required for specimen, mL,M2= molarity of ZnCl
31、2solution,S = sample used, g, and5.59 = millimolar weight of Fe 10011. Precision and Bias511.1 The precision estimates are based on an interlaboratorystudy in which one operator in seven different laboratoriesanalyzed in duplicate on two different days two samples of irondrier containing 6 % and 3 %
32、 iron. The 6 % iron drier was acommercially supplied sample and the 3 % drier was obtainedby quantitative dilution of the 6 % drier. The results wereanalyzed statistically in accordance with Practice E180 and thewithin-laboratory coefficient of variation was found to be0.26 % relative at 12 degrees
33、of freedom and the between-laboratories coefficient of variation was 1.46 % relative at 105Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1021. ContactASTM CustomerService at serviceastm.org.D3804 02 (2014)2degrees of freedo
34、m. Based on these coefficients, the followingcriteria should be used for judging the acceptability of resultsat the 95 % confidence level: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 d
35、iffer by more than0.8 % relative.11.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtained by operators in different labo-ratories should be considered suspect if they differ by morethan 4.6 % relative.11.2 BiasBias cannot be determined because there is noaccepted stand
36、ard for iron in paint driers.12. Keywords12.1 driers; EDTA methods; iron driers; paint driersASTM 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 determinati
37、on of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdr
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