D2193-06乙烯基醋酸盐中氢醌的测定

Designation: D 2193 – 06 Standard Test Method for Hydroquinone in Vinyl Acetate1 This standard is issued under the fixed designation D 2193; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript 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, commercially available, vinyl acetate. 1.2 For purposes of determining conformance of an ob- served or a calculated value using this test method to relevant specifications, test result(s) shall be rounded off “to the nearest unit” in the last right-hand digit used in expressing the specification limit, in accordance with Practice E 29. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 1.5 For hazard information and guidance, see the supplier’s Material Safety Data Sheet. 2. Referenced Documents 2.1 ASTM Standards: 2 D 1193 Specification for Reagent Water E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 3. Summary of Test Method 3.1 The vinyl acetate is evaporated at room temperature in a stream of inert gas or clean air to minimize the loss of hydroquinone by evaporation. The hydroquinone is dissolved in water and titrated with dilute standardized ceric acid sulfate using diphenylamine as indicator. 4. Significance and Use 4.1 This test method provides a measurement of inhibitor level in vinyl acetate. The results of these measurements can be used for specification acceptance. 5. Apparatus 5.1 Buret, 25-mL, graduated in 0.1-mL subdivisions. 5.2 Beakers, 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. Reagents 6.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Commit- tee on Analytical Reagents of the American Chemical Society, where such specifications are available.3 Other grades may be used provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 6.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type IV of Specification D 1193. 6.3 Ceric Acid Sulfate, Standard Solution (0.002 N)— Dissolve 1.096 g of ceric ammonium nitrate ((NH4)2- Ce(NO3)6) in 28.0 mL of concentrated sulfuric acid (H2SO4, sp gr 1.84) contained in a 50-mL beaker. Slowly pour the ceric solution, while stirring, into 200 mL of water contained in a 600-mL beaker. When solution is complete, transfer this mixture to a 1000-mL volumetric flask and dilute to the mark with water. 1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates. Current edition approved June 1, 2006. Published June 2006. Originally approved in 1963. Last previous edition approved in 2001 as D 2193 – 97 (2001). 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 3 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and 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 States. Copyright ASTM International, 100 Barr Harbo Drive, West Conshohocken, Pennsylvania 19428, USA Distributed under ASTM license agreement by Shanghai Institute of Standardization(SIS) Tel:86-21-64370807 ASTM International 版权所有, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428, USA 由上海市化研究院（SIS）根据ASTM授权进行销售 地址：上海市长乐路1219/1227号 邮编：200031 联系电话：86-21-64370807 6.4 Diphenylamine Indicator Solution—Dissolve 0.1 g of diphenylamine in 100 mL of H2SO4(sp gr 1.84) and store this solution in a brown glass bottle. 6.5 Hydroquinone Standard—Dissolve 200.0 mg of hydro- quinone, weighed to the nearest 0.1 mg, in water and dilute to 1000.0 mL in a volumetric flask. This solution is unstable and should be discarded after 1 week of normal use. 7. Standardization 7.1 Pipet 10-mL portions of the hydroquinone standard (see 6.5) into each of two 100-mL Erlenmeyer flasks. Add 3 drops of diphenylamine indicator solution to each flask. Using a 25-mL buret, titrate the contents of each flask with ceric acid sulfate solution to a faint blue end point that is permanent for 15 s. The titrations should be approximately 20 mL and should agree within 0.5 mL. Average the two values and use in the calculations (Section 9). 8. Procedure 8.1 Pipet 50 mL of the vinyl acetate sample into each of two 250-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 filter before entering the specimen flasks. Maintain the flow of gas just short of a level causing splattering of the specimen. That part of the delivery tube in the flask must be of metal, glass, or an inert plastic, such as polyethylene or polytetrafluoroethylene (PTFE). 8.3 After complete evaporation, which requires 45 to 60 min, remove the gas stream and dissolve the hydroquinone in 25 mL of water. 8.4 Add 3 drops of diphenylamine indicator solution to each flask using the same dropper as in the reagent standardization. Titrate each solution with the ceric acid sulfate reagent to a light blue end point that is permanent for 15 s. 9. Calculation 9.1 Calculate the parts per million of hydroquinone, H, in the sample as follows: H 5 [~V 3 F!/S] 3 1000 (1) where: V = millilitres of ceric acid sulfate reagent required for titration of the specimen, (see 8.4), F = factor (Section 7) = milligrams of hydroquinone in 10-mL aliquot/average millilitres of ceric acid sulfate reagent, and S = grams of sample used = 50 3 specific gravity. 10. Report 10.1 Report the concentration of hydroquinone to the near- est 0.1 ppm. 11. Precision and Bias 11.1 The following criteria should be used for judging the acceptability of results at the 95 % confidence level: 11.1.1 Repeatability—Two results, each the mean of dupli- cate determinations, obtained by the same analyst should be considered suspect if they differ by more than 0.3 ppm. 11.1.2 Reproducibility—Two results, each the mean of du- plicate determinations, obtained by analysts in different labo- ratories should be considered suspect if they differ by more than 1.0 ppm. NOTE 1—The preceding precision statements are based upon an inter- laboratory study on two samples of vinyl acetate containing 4.6 and 15.3 ppm hydroquinone. Each sample was analyzed in duplicate on two different days by one analyst in each of five different laboratories. 11.2 Bias—This bias of this test method has not been determined because there is no appropriate standard available. 12. Keywords 12.1 HQ; hydroquinone; vinyl acetate SUMMARY OF CHANGES Committee 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. (Approved June 1, 2006.) (1) Added reference to Practice E 29 in the Scope section. (2) Added Practice E 29 to list of Referenced Documents. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of 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 and if not revised, either reapproved or withdrawn. 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D 2193 – 06 2 Copyright ASTM International, 100 Barr Harbo Drive, West Conshohocken, Pennsylvania 19428, USA Distributed under ASTM license agreement by Shanghai Institute of Standardization(SIS) Tel:86-21-64370807 ASTM International 版权所有, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428, USA 由上海市标准化研究院（SIS）根据ASTM授权协议进行销售 地址：上海市长乐路1219/1227号 邮编：200031 联系电话：86-21-64370807 Scope Referenced Documents Summary of Test Method Significance and Use Apparatus Reagents Standardization Procedure Calculation Report Precision and Bias Keywords