1、Designation: D4590 13Standard 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 oforiginal adop
2、tion 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 ofresidual 4-tertia
3、ry-butylcatechol (TBC) in styrene monomer orAMS in the 1 to 100 mg/kg 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 co
4、ncentration 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 uni
5、ts 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 regu
6、latory limitations prior to use. For specificstatements on hazards, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD3437 Practice for Sampling and Handling Liquid CyclicProductsD4790 Terminology of Aromatic Hydrocarbons and RelatedChemicalsD6809 Guide f
7、or Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Oth
8、er Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 See Terminology D4790 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 the pinkcol
9、or 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 qualitycontrol.6
10、. 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 to the sam
11、ple 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 responsibili
12、ty ofSubcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 AromaticHydrocarbons.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 1986. Last previous edition approved in 2009 as D4590 09. DOI:10.1520/D4590-13.2For referenced ASTM standards, visit the ASTM websit
13、e, www.astm.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
14、, Washington, DC 20401, http:/www.access.gpo.gov.*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 States1Sample Pipet,mL0.15 NaOHPipetor,LMethanol Pipetor,L15 300 6005 100 2007.
15、 Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specification of the Committeeon Analytical Reagents of the American Chemical Society,where such specifications are availab
16、le.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.7.2 4-Tertiary-Butylcatechol, Mp 52 to 55C.7.3 Toluene, ACS reagent grade.7.4 Methanol, reagent grade.7.5 n-Octanol, reage
17、nt 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 bottle. Thisre
18、agent 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 StandardThis standard may be purchasedif desired. Prepare a stock solution by weighing 0.500
19、6 0.001g of 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 aconcentration of approximately 1000 mg/kg TBC in tolueneand the exact concentration can be calculated using Eq 1. Thisstandard should have a shelf life of one year or better if s
20、toredin a refrigerator or freezer. Storing standards in amber bottlessignificantly reduces degradation of standards with time.mg TBC/kg toluene 5 g of TBC! 3 Purity of TBC!3 106!#/g of toluene (1)7.9 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean any reagen
21、t conformingto type I as defined in Specification D1193.8. 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 so
22、lution, is very corrosiveto the skin. It is also a systemic poison when taken orally orabsorbed in quantity through the skin.8.3 Flammable HazardsStyrene monomer is flammableand can polymerize exothermally under a variety of conditions,most especially in the presence of peroxides, mineral acids, and
23、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, and 10 mLs of T
24、BC stock standard to 100 mLs withtoluene. Record the actual concentrations generated to thenearest 0.5 mg/kg.NOTE 1Both the stock solution and toluene diluent should be at roomtemperature. Temperature differences will cause dilution errors due tovariations in density.10.2 Determine the absorbance of
25、 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 a straight line. The maximumabsorbance should be within the absorbance range of the spectrometer. Ifnot, repeat the calibratio
26、n 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 container.11.3 Verify that the alcoholic NaOH reagent and pipetor arefree of particulates.NOTE 3The particulates formed in the sod
27、ium hydroxide reagent fromexposure to carbon dioxide in the atmosphere will scatter light and maycause an error in the determination.11.4 Add 300 L of alcoholic NaOH reagent to the con-tainer and mix vigorously with a vortex mixer for 30 s.NOTE 4If a vortex mixer is not available, continuous vigorou
28、sshaking 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 container and shake forabout 15 s, creating a clear solution from the reaction emulsion.11.6 Measure the absorbance at 490 nm as s
29、oon as possibleand within 5 min.11.7 Read the concentration in mg/kg TBC from the graph.Calculate the inhibitor content using Eq 2 for density correc-tion:Inhibitor Content, mg/kg 5 Value from curve!3 toluene density!/sample density!# (2)12. Report12.1 Report the inhibitor content as mg/kg (or ppm)
30、ofp-tert-butylcatechol.4Reagent 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, U.K., and the U
31、nited States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D4590 13213. Precision and Bias13.1 The following criteria should be used to judge theacceptability of results obtained by this test method (95 %confidence level). The precision criteria were de
32、rived from anILS that was conducted using six laboratories analyzing threesample of unknown concentration of TBC with two determi-nations for each sample. Each determination was the result ofone measurement as specified in this standard. Practice E691was followed for the design and analysis of the d
33、ata; the detailsare given in ASTM Research Report RR:D16-1009.513.2 Intermediate Precision (formerly calledRepeatability)Results in the same laboratory should not beconsidered suspect unless they differ by more than the valuesshown in Table 1. Results differing by less than “r”havea95% probability o
34、f being correct.13.3 ReproducibilityResults submitted by two laborato-ries should not be considered suspect unless they differ bymore than the values shown in Table 1. Results differing by lessthan “R” have a 95 % probability of being correct.13.4 BiasThere is a bias associated with running the test
35、method 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 lower than theactual amounts added. However, at the 99 % confidence level,the bias is not statistically significant.14. Quality Gu
36、idelines14.1 Laboratories shall have a quality control system inplace.14.1.1 Confirm the performance of the test instrument ortest method by analyzing a quality control sample followingthe guidelines for standard statistical quality control practices.14.1.2 A quality control sample is a stable mater
37、ial isolatedfrom the production process and representative of the samplebeing analyzed.14.1.3 When QA/QC protocols are already established inthe testing facility, these protocols are acceptable when theyconfirm the validity of test results.14.1.4 When there are no QA/QC protocols established inthe t
38、esting facility, use the guidelines described in GuideD6809 or similar statistical quality control practices.15. Keywords15.1 alpha-methylstyrene; AMS; para-tertiary butyl cat-echol; PTBC; styrene, inhibitor content; styrene, TBC content;TBC in styreneSUMMARY OF CHANGESCommittee D16 has identified t
39、he location of selected changes to this standard since the last issue (D459009)that may impact the use of this standard. (Approved June 1, 2013.)(1) All sections updated to current D16 Editorial Guidelines.ASTM International takes no position respecting the validity of any patent rights asserted in
40、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 responsibility.This standard is subject to revision at any time by the res
41、ponsible 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 International Headquarters. Your comments will receive caref
42、ul 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 shown below.This standard is copyrighted by ASTM International
43、, 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 AS
44、TM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D16-1009.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 9.94D4590 133
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