ASTM D4590-2018 Standard Test Method for Colorimetric Determination of p-tert-Butylcatechol In Styrene Monomer or AMS (&x3b1 &x2013 Methylstyrene) by Spectrophotometry.pdf

1、Designation: D4590 13D4590 18Standard Test Method forColorimetric Determination of p-tert-Butylcatechol In StyreneMonomer or AMS (Methylstyrene) by Spectrophotometry1This standard is issued under the fixed designation D4590; the number immediately following the designation indicates the year oforigi

2、nal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is applicable to the determination of residual

3、 4-tertiary-butylcatechol (TBC) in styrene monomer or AMSin the 1 to 100 mg/kg range. Any other compound producing color at 490 nm when contacted with aqueous sodium hydroxidesolution will interfere. It may be compensated for by including it in the preparation of the standard solutions, if its ident

4、ity andconcentration in the sample are known.1.2 In determining the conformance of the test results using this method to applicable specifications, results shall be roundedoff in accordance with the rounding-off method of Practice E29. The limit of detection is 0.2 mg/kg while the limit of quantitat

5、ionis 0.8 mg/kg based on the ILS data in Table 1.1.3 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 responsi

6、bilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. For specific statements on hazards, see Section 8.1.5 This international standard was developed in accordance wi

7、th internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:

8、2D1193 Specification for Reagent WaterD3437 Practice for Sampling and Handling Liquid Cyclic ProductsD4790 Terminology of Aromatic Hydrocarbons and Related ChemicalsD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE29 Practice for Using

9、Significant Digits in Test Data to Determine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200 33. Terminology3.1 See Terminology D4790 for def

10、inition of terms used in this standard.4. Summary of Method4.1 Color is developed in the specimen by the addition of caustic in a methanol-octanol solvent. The intensity of the pink coloris measured with a spectrometer and compared to a calibration curve for quantitation.1 This test method is under

11、the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the directresponsibility of Subcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic Hydrocarbons.Current edition approved June 1, 2013June 1, 2018. Published June

12、 2013June 2018. Originally approved in 1986. Last previous edition approved in 20092013 asD4590 09.D4590 13. DOI: 10.1520/D4590-13.10.1520/D4590-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standar

13、dsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.This document is not an ASTM standard a

14、nd is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only

15、 the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Us

16、e5.1 This test method is suitable for determining the quantity of TBC inhibitor, both for the protection against polymerizationwhile in transit and storage, and for internal quality control.6. Apparatus6.1 Visible Range Spectrometer, equipped with absorption cells providing light paths from 1 to 5 c

17、m for use at approximately490 nm.6.2 Volumetric Pipets and PipetorsThe sample pipet volume should be sized to fill the spectrometer absorption cell. Pipetorvolumes must be scaled to the sample volume. This procedure is written using a 15 mLsample volume. The following table showshow reagent pipetor

18、volumes could be scaled to use a 5 mL sample volume.TABLE 1 Intermediate Precision and ReproducibilityTBC ObservedConcentration Repeatability Reproducibility4.7 0.23 0.9415.2 0.47 5.0824.5 1.55 4.9194.6 3.98 9.94D4590 182Sample Pipet,mL0.15 NaOHPipetor,LMethanol Pipetor,L15 300 6005 100 2007. Reagen

19、ts and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specification of the Committee onAnalytical Reagents of theAmerican Chemical Society, where suchspecifications are available.4 Ot

20、her grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.7.2 4-Tertiary-Butylcatechol, Mp 52 to 55C.7.3 Toluene, ACS reagent grade.7.4 Methanol, reagent grade.7.5 n-Octanol, reagent g

21、rade.7.6 Aqueous Sodium Hydroxide, 10 Normal (10N), reagent grade.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 mLof n-octanol and then 0.75 mLof water. Store the reagent in an amber glass bottle. This reag

22、entcan be used immediately after preparation and is stable for at least 2 months. To reduce exposure of the reagent to the atmosphere,transfer enough for several samples to a small clean vial.7.8 TBC Stock StandardThis standard may be purchased if desired. Prepare a stock solution by weighing 0.500

23、6 0.001 gof TBC to the nearest 0.0001 g into 500 6 1 g of toluene (weighed to the nearest 0.1 g). This solution will have a concentrationof approximately 1000 mg/kg TBC in toluene and the exact concentration can be calculated using Eq 1. This standard should havea shelf life of one year or better if

24、 stored in a refrigerator or freezer. Storing standards in amber bottles significantly reducesdegradation of standards with time.mg TBC/kg toluene5g of TBC! 3Purity of TBC! 3106!#/g of toluene (1)7.9 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean any reage

25、nt conforming totype I as defined in Specification D1193.8. Hazards8.1 Consult current OSHAregulations, suppliers Material suppliers Safety Data Sheets, and local regulations for all materialsused in this test method.8.2 Handling Precautionsp-tert-butylcatechol, particularly when molten or in concen

26、trated solution, is very corrosive to theskin. It is also a systemic poison when taken orally or absorbed in quantity through the skin.8.3 Flammable HazardsStyrene monomer is flammable and can polymerize exothermally under a variety of conditions, mostespecially in the presence of peroxides, mineral

27、 acids, and Lewis acids such as aluminum chloride.9. Sampling and Handling9.1 Sample the material in accordance with Practice D3437.10. Preparation of Calibration Curve10.1 Prepare standards of approximately 5, 10, 20, 30, 40, 50, 70, and 100 mg/kg TBC in toluene by diluting 0.5, 1, 2, 3, 4,5, 7, an

28、d 10 mLsmL of TBC stock standard to 100 mLsmL with toluene. Record the actual concentrations generated to the nearest0.5 mg/kg.NOTE 1Both the stock solution and toluene diluent should be at room temperature. Temperature differences will cause dilution errors due to variationsin density.10.2 Determin

29、e the absorbance of each standard solution and one reagent blank in accordance with Section 11.10.3 Plot absorbance versus concentration on standard graph paper.NOTE 2The plot should be close to a straight line. The maximum absorbance should be within the absorbance range of the spectrometer. If not

30、, repeatthe calibration with a spectrometer cell that has less path length.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laborat

31、ory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D4590 18311. Procedure11.1 Zero the spectrometer with the specimen to be analyzed.11.2 Add 15 mL of specimen to a clean round container.11

32、.3 Verify that the alcoholic NaOH reagent and pipetor are free of particulates.NOTE 3The particulates formed in the sodium hydroxide reagent from exposure to carbon dioxide in the atmosphere will scatter light and may causean error in the determination.11.4 Add 300 L of alcoholic NaOH reagent to the

33、 container and mix vigorously with a vortex mixer for 30 s.NOTE 4If a vortex mixer is not available, continuous vigorous shaking for 30 s is required. Rapid reaction completion depends on the formulationof an emulsion of aqueous NaOH in the sample mixture.11.5 Add 600 L of methanol to the container

34、and shake for about 15 s, creating a clear solution from the reaction emulsion.11.6 Measure the absorbance at 490 nm as soon as possible and within 5 min.11.7 Read the concentration in mg/kg TBC from the graph. Calculate the inhibitor content using Eq 2 for density correction:Inhibitor Content,mg/kg

35、5Value from curve! 3toluene density!/sample density!# (2)12. Report12.1 Report the inhibitor content as mg/kg (or ppm) of p-tert-butylcatechol.-butylcatechol to the nearest 0.1 mg/kg12.2 Results less than the LOD should be reported as 0.2 mg/kg.13. Precision and Bias513.1 The following criteria shou

36、ld be used to judge the acceptability of results obtained by this test method (95 % confidencelevel). The precision criteria were derived from an ILS that was conducted using six laboratories analyzing three sample ofunknown concentration of TBC with two determinations for each sample. Each determin

37、ation was the result of one measurementas specified in this standard. Practice E691 was followed for the design and analysis of the data; the details are given in ASTMResearch Report RR:D16-1009.13.2 Intermediate Precision (formerly called Repeatability)Results in the same laboratory should not be c

38、onsidered suspectunless they differ by more than the values shown in Table 1. Results differing by less than “r” have a 95 % probability of beingcorrect.13.3 ReproducibilityResults submitted by two laboratories should not be considered suspect unless they differ by more thanthe values shown in Table

39、 1. Results differing by less than “R” have a 95 % probability of being correct.13.4 BiasThere is a bias associated with running the test method that is statistically significant at the 95 % confidence level.The bias for the unknown samples is an average absolute value of 0.6 mg/kg with the observed

40、 results lower than the actualamounts added. However, at the 99 % confidence level, the bias is not statistically significant.14. Quality Guidelines14.1 Laboratories shall have a quality control system in place.14.1.1 Confirm the performance of the test instrument or test method by analyzing a quali

41、ty control sample following theguidelines for standard statistical quality control practices.14.1.2 Aquality control sample is a stable material isolated from the production process and representative of the sample beinganalyzed.14.1.3 When QA/QC protocols are already established in the testing faci

42、lity, these protocols are acceptable when they confirmthe validity of test results.14.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 orsimilar statistical quality control practices.15. Keywords15.1 alpha-methylstyrene; AMS; para

43、-tertiary butyl catechol; PTBC; styrene, inhibitor content; styrene, TBC content; TBC instyrene5 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D16-1009. Contact ASTM CustomerService at serviceastm.org.D4590 184SUMMARY OF CHANG

44、ESCommittee D16 has identified the location of selected changes to this standard since the last issue(D459009)13) that may impact the use of this standard. (Approved June 1, 2013.)2018.)(1) All sections updated to current D16 Editorial Guidelines.Minor changes to sections 1, 8, and 12.ASTM Internati

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47、 addressed to ASTM 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

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