1、Designation: D 2193 06Standard Test Method forHydroquinone in Vinyl Acetate1This standard is issued under the fixed designation D 2193; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of hydro-quinone in the range from 1 to 20 ppm in refined, commerciallyavailable, vinyl acetate.1.2 For purpo
3、ses of determining conformance of an ob-served or a calculated value using this test method to relevantspecifications, test result(s) shall be rounded off “to the nearestunit” in the last right-hand digit used in expressing thespecification limit, in accordance with Practice E 29.1.3 The values stat
4、ed in SI units are to be regarded asstandard. 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
5、 health practices and determine the applica-bility of regulatory limitations prior to use.1.5 For hazard information and guidance, see the suppliersMaterial Safety Data Sheet.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in
6、 Test Data toDetermine Conformance with Specifications3. Summary of Test Method3.1 The vinyl acetate is evaporated at room temperature in astream of inert gas or clean air to minimize the loss ofhydroquinone by evaporation. The hydroquinone is dissolvedin water and titrated with dilute standardized
7、ceric acid sulfateusing diphenylamine as indicator.4. Significance and Use4.1 This test method provides a measurement of inhibitorlevel in vinyl acetate. The results of these measurements can beused for specification acceptance.5. Apparatus5.1 Buret, 25-mL, graduated in 0.1-mL subdivisions.5.2 Beake
8、rs, 50 and 600-mL capacity.5.3 Volumetric Flask, 1000-mL capacity.5.4 Erlenmeyer Flasks, 100 and 250-mL capacity.5.5 Nitrogen Cylinder, or source of clean air.5.6 Pipets, 10 and 50-mL capacity.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indica
9、ted, 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.3Other grades may beused provided it is first ascertained that the reagent is ofsufficiently high purity to permi
10、t its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D 1193.6.3 Ceric Acid Sulfate, Standard Solution (0.002 N)Dissolve 1.096 g of ceric ammonium
11、nitrate (NH4)2-Ce(NO3)6) in 28.0 mL of concentrated sulfuric acid (H2SO4,spgr 1.84) contained in a 50-mL beaker. Slowly pour the cericsolution, while stirring, into 200 mL of water contained in a600-mL beaker. When solution is complete, transfer thismixture to a 1000-mL volumetric flask and dilute t
12、o the markwith water.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates.Current edition approved June 1, 2006. Publish
13、ed June 2006. Originallyapproved in 1963. Last previous edition approved in 2001 as D 2193 97 (2001).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 D
14、ocument Summary page onthe 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
15、, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sta
16、tes.6.4 Diphenylamine Indicator SolutionDissolve 0.1 g ofdiphenylamine in 100 mL of H2SO4(sp gr 1.84) and store thissolution in a brown glass bottle.6.5 Hydroquinone StandardDissolve 200.0 mg of hydro-quinone, weighed to the nearest 0.1 mg, in water and dilute to1000.0 mL in a volumetric flask. This
17、 solution is unstable andshould be discarded after 1 week of normal use.7. Standardization7.1 Pipet 10-mL portions of the hydroquinone standard (see6.5) into each of two 100-mL Erlenmeyer flasks. Add 3 dropsof diphenylamine indicator solution to each flask. Using a25-mL buret, titrate the contents o
18、f each flask with ceric acidsulfate solution to a faint blue end point that is permanent for15 s. The titrations should be approximately 20 mL and shouldagree within 0.5 mL. Average the two values and use in thecalculations (Section 9).8. Procedure8.1 Pipet 50 mL of the vinyl acetate sample into eac
19、h of two250-mL flasks.8.2 Evaporate the specimens at room temperature by pass-ing a stream of cylinder nitrogen gas or clean air into the flasks.Bench-line air should be passed through a fiberglass filterbefore entering the specimen flasks. Maintain the flow of gasjust short of a level causing splat
20、tering of the specimen. Thatpart of the delivery tube in the flask must be of metal, glass, oran inert plastic, such as polyethylene or polytetrafluoroethylene(PTFE).8.3 After complete evaporation, which requires 45 to 60min, remove the gas stream and dissolve the hydroquinone in25 mL of water.8.4 A
21、dd 3 drops of diphenylamine indicator solution to eachflask using the same dropper as in the reagent standardization.Titrate each solution with the ceric acid sulfate reagent to alight blue end point that is permanent for 15 s.9. Calculation9.1 Calculate the parts per million of hydroquinone, H,inth
22、e sample as follows:H 5 V 3 F!/S 3 1000 (1)where:V = millilitres of ceric acid sulfate reagent required fortitration of the specimen, (see 8.4),F = factor (Section 7) = milligrams of hydroquinone in10-mL aliquot/average millilitres of ceric acid sulfatereagent, andS = grams of sample used = 50 3 spe
23、cific gravity.10. Report10.1 Report the concentration of hydroquinone to the near-est 0.1 ppm.11. Precision and Bias11.1 The following criteria should be used for judging theacceptability of results at the 95 % confidence level:11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinati
24、ons, obtained by the same analyst should beconsidered suspect if they differ by more than 0.3 ppm.11.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtained by analysts in different labo-ratories should be considered suspect if they differ by morethan 1.0 ppm.NOTE 1The p
25、receding precision statements are based upon an inter-laboratory study on two samples of vinyl acetate containing 4.6 and 15.3ppm hydroquinone. Each sample was analyzed in duplicate on twodifferent days by one analyst in each of five different laboratories.11.2 BiasThis bias of this test method has
26、not beendetermined because there is no appropriate standard available.12. Keywords12.1 HQ; hydroquinone; vinyl acetateSUMMARY OF CHANGESCommittee D01.35 has identified the location of selected changes to this standard since the last issue(D 2193 - 97 (2001) that may impact the use of this standard.
27、(Approved June 1, 2006.)(1) Added reference to Practice E29in the Scope section. (2) Added Practice E29to list of Referenced Documents.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this stand
28、ard are expressly advised that determination 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 andi
29、f not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, wh
30、ich you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at 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).D2193062
