ASTM D4590-2006 Standard Test Method for Colorimetric Determination of p-tert-Butylcatechol In Styrene Monomer or AMS (alpha-Methylstyrene) by Spectrophotometry《用分光光度法对乙烯基苯或AMS(α-甲.pdf

1、Designation: D 4590 06Standard Test Method forColorimetric Determination of p-tert-Butylcatechol In StyreneMonomer or AMS (aMethylstyrene) by Spectrophotometry1This standard is issued under the fixed designation D 4590; the number immediately following the designation indicates the year oforiginal a

2、doption 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. Scope*1.1 This test method is applicable to the determination ofresidual 4-te

3、rtiary-butylcatechol (TBC) in styrene monomer orAMS in the 1 to 100 ppm range. Any other compoundproducing color at 490 nm when contacted with aqueoussodium hydroxide solution will interfere. It may be compen-sated for by including it in the preparation of the standardsolutions, if its identity and

4、concentration in the sample areknown.1.2 In determining the conformance of the test results usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.3 The values stated in SI units are to be regarded asstandard. No other u

5、nits 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 applica-bility of re

6、gulatory limitations prior to use. For specificstatements on hazards, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 3437 Practice for Sampling and Handling Liquid CyclicProductsD 4790 Terminology of Aromatic Hydrocarbons and Re-lated ChemicalsD 6809

7、 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Meth

8、od2.2 Other Document:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120033. Terminology3.1 See Terminology D 4790 for definition of terms used inthis standard.4. Summary of Method4.1 Color is developed in the specimen by the addition ofcaustic in a methanol-octanol solvent. The intensity of

9、the pinkcolor is measured with a spectrometer and compared to acalibration curve for quantitation.5. Significance and Use5.1 This test method is suitable for determining the quantityof TBC inhibitor, both for the protection against polymeriza-tion while in transit and storage, and for internal quali

10、tycontrol.6. Apparatus6.1 Visible Range Spectrometer, equipped with absorptioncells providing light paths from 1 to 5 cm for use at approxi-mately 490 nm.6.2 Volumetric Pipets and PipetorsThe sample pipet vol-ume should be sized to fill the spectrometer absorption cell.Pipetor volumes must be scaled

11、 to the sample volume. Thisprocedure is written using a 15 mL sample volume. Thefollowing table shows how reagent pipetor volumes could bescaled to usea5mLsample volume.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct r

12、esponsibility ofSubcommittee D16.07 on Styrene, Ethylbenzene, and C9and C10AromaticHydrocarbons.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1986. Last previous edition approved in 2000 as D 4590 00.2For referenced ASTM standards, visit the ASTM website, www.astm

13、.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.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washingto

14、n, DC 20401.1*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.Sample Pipet,mL0.15 NaOH Pipetor,LMethanol Pipetor,L15 300 6005 100 2007. Reagents and Materials7.1 Purity

15、of ReagentsWhere unspecified, chemicals shallbe reagent grade and conform to recognized specifications ifsuch exist.4If found to have no adverse effect on accuracy,other grades may be used.7.2 4-Tertiary-Butylcatechol, Mp 52 to 55C.7.3 Toluene, ACS reagent grade.7.4 Methanol, reagent grade.7.5 n-Oct

16、anol, reagent grade.7.6 Aqueous Sodium Hydroxide, 10 Normal (10N), reagentgrade.7.7 Alcoholic Sodium Hydroxide, approximately 0.15 N.Mix 0.75 mL of 10N Aqueous Sodium Hydroxide with 25 mLmethanol. With stirring, add 25 mL of n-octanol and then 0.75mL of water. Store the reagent in an amber glass bot

17、tle. Thisreagent can be used immediately after preparation and is stablefor at least 2 months. To reduce exposure of the reagent to theatmosphere, transfer enough for several samples to a smallclean vial.7.8 TBC Stock StandardWeigh 0.500 6 1 g of TBC into500 6 1 g of toluene. This solution will cont

18、ain 1000 ppmTBC. This standard should have a shelf life of one year orbetter if stored in a refrigerator or freezer. Storing standards inamber bottles significantly reduces degradation of standardswith time.7.9 Unless otherwise indicated, references to water shall beunderstood to mean any reagent wa

19、ter as defined in Specifica-tion D 1193.8. Hazards8.1 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.8.2 Handling Precautionsp-tert-butylcatechol, particu-larly when molten or in concentrated solution, is very c

20、orrosiveto the skin. It is also a systemic poison when taken orally orabsorbed in quantity through the skin.8.3 Flammable HazardsStyrene monomer is flammableand polymerizes exothermally in the presence of peroxide,mineral acids, and aluminum chloride.9. Sampling9.1 Collect the samples in accordance

21、with Practice D 3437.10. Preparation of Calibration Curve10.1 Prepare standards of 5, 10, 20, 30, 40, 50, 70, and 100ppm (mg/kg) TBC in toluene by diluting 0.5, 1, 2, 3, 4, 5, 7,and 10 mLs of TBC stock standard to 100 mLs with toluene.NOTE 1Both the stock solution and toluene diluent should be at ro

22、omtemperature. Temperature differences will cause dilution errors due tovariations in density.10.2 Determine the absorbance of each standard solutionand one reagent blank in accordance with Section 11.10.3 Plot absorbance versus concentration on standardgraph paper.NOTE 2The plot should be close to

23、a straight line. The maximumabsorbance should be within the absorbance range of the spectrometer. Ifnot, repeat the calibration with a spectrometer cell that has less pathlength.11. Procedure11.1 Zero the spectrometer with the specimen to be ana-lyzed.11.2 Add 15 mL of specimen to a clean round cont

24、ainer.11.3 Verify that the alcoholic NaOH reagent and pipetor arefree of particulates.NOTE 3The particulates formed in the sodium hydroxide reagentfrom exposure to carbon dioxide in the atmosphere will scatter light andmay cause an error in the determination.11.4 Add 300 L of alcoholic NaOH reagent

25、to the con-tainer and mix vigorously with a vortex mixer for 30 s.NOTE 4If a vortex mixer is not available, continuous vigorousshaking for 30 s is required. Rapid reaction completion depends on theformulation of an emulsion of aqueous NaOH in the sample mixture.11.5 Add 600 L of methanol to the cont

26、ainer and shake forabout 15 s, creating a clear solution from the reaction emulsion.11.6 Measure the absorbance at 490 nm as soon as possibleand within 5 min.11.7 Read the concentration in parts per million TBC fromthe graph. Calculate the inhibitor content using Eq 1 for densitycorrection:Inhibitor

27、 Content, mg/kg 5 Value from curve!3 toluene density!/sample density!#(1)12. Report12.1 Report the inhibitor content as parts per million (mg/kg) of p-tert-butylcatechol.13. Precision and Bias513.1 The interlaboratory study included six laboratoriesanalyzing three samples of unknown concentration of

28、 TBC andtwo determinations for each sample. Each determination wasthe result of one measurement as specified in this standard.Results of the interlaboratory study were calculated usingPractice E 691.13.2 RepeatabilityResults in the same laboratory shouldnot be considered suspect unless they differ b

29、y more than thevalues shown in Table 1.13.3 ReproducibilityResults submitted by two laborato-ries should not be considered suspect unless they differ bymore than the values shown in Table 1.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For su

30、ggestions 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.5Supporting data are availa

31、ble from ASTM International Headquarters. RequestRR: D161009.D459006213.4 BiasThere is a bias associated with running the testmethod that is statistically significant at the 95 % confidencelevel. The bias for the unknown samples is an average absolutevalue of 0.6 mg/kg with the observed results lowe

32、r than theactual amounts added. However, at the 99 % confidence level,the bias is not statistically significant.14. Quality Guidelines14.1 Refer to Guide D 6809 for suggested QA/QC activitiesthat can be used as a part of this test method. It is recom-mended that the operator of this test method sele

33、ct and performrelevant QA/QC activities like the ones in Guide D 6809 tohelp ensure the quality of data generated by this test method.15. Keywords15.1 alpha-methylstyrene; AMS; para-tertiary butyl cat-echol; PTBC; styrene, inhibitor content; styrene, TBC content;TBC in styreneSUMMARY OF CHANGESCommi

34、ttee D16 has identified the location of selected changes to this standard since the last issue(D 4590 - 00) that may impact the use of this standard. (Approved June 1, 2006.)(1) 6.2 Allows for pipetors and adjusting volumes toaccommodate alternative sample cells.(2) 7.7 New recipe for alcoholic sodi

35、um hydroxide. Allowsfor use of solution immediately and has a longer shelf life.(3) Section 11 Sample size and reagents are increasedthreefold.(4) 11.7 Density correction applied to Inhibitor Contentcalculation.(5) Section 13 A new precision statement has been added.ASTM International takes no posit

36、ion respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibilit

37、y.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 withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM

38、 International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which 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 s

39、hown 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).TABLE 1 Intermediate Precision and ReproducibilityTBC ObservedConcentrationRepeatability Reproducibility4.7 0.23 0.9415.2 0.47 5.0824.5 1.55 4.9194.6 3.98 9.94D4590063