1、Designation: D6144 08 D6144 12Standard Test Method forAnalysis of AMS (-Methylstyrene) by Capillary GasChromatography1This standard is issued under the fixed designation D6144; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 covers the determination of the purity of AMS (-methylstyrene) by gas chromatography. Calibrat
3、ion ofthe gas chromatography system is done by the external standard calibration technique.1.2 This test method has been found applicable to the measurement of impurities such as cumene, 3-methyl-2-cyclopentene-1-one, n-propylbenzene, tert-butylbenzene, sec-butylbenzene, cis-2-phenyl-2-butene, aceto
4、phenone, 1-phenyl-1-butene, 2-phenyl-2-propanol, trans-2-phenyl-2-butene, m-cymene, p-cymene, and phenol, which are common to the manufacturing process of AMS.The method has also been found applicable for the determination of para-tertiary-butylcatechol typically added as a stabilizer toAMS. The imp
5、urities in AMS can be analyzed over a range of 5 to 800 mg/kg by this method. (See Table 1.) The limit of detectionfor these impurities is typically in the range of 5 to 10 mg/kg. (See Table 1.)1.3 In determining the conformance of the test results using this method to applicable specifications, res
6、ults shall be roundedoff in accordance with the rounding-off method of Practice E29.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all the safety concerns, if any, associated
7、with its use. It is the responsibility ofthe user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see Section 8.2. Referenced Documents2.1 ASTM Standards:2D3437 Practice for S
8、ampling and Handling Liquid Cyclic ProductsD4307 Practice for Preparation of Liquid Blends for Use as Analytical StandardsD4790 Terminology of Aromatic Hydrocarbons and Related ChemicalsD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE2
9、9 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE355 Practice for Gas Chromatography Terms and RelationshipsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1510 Practice for Installing Fused Silica Ope
10、n Tubular Capillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.120033. Terminology3.1 See Terminology D4790 for definition of terms used in this test method.4. Summary of Test Method4.1 AMS (-methylstyrene) is analyzed by a gas chromatograp
11、h (GC) equipped with a flame ionization detector (FID). Aprecisely repeatable volume of the sample to be analyzed is injected onto the gas chromatograph. The peak areas of the impurities1 This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons and Related Chemicals
12、and is the direct responsibility of SubcommitteeD16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic Hydrocarbons.Current edition approved June 1, 2008Dec. 1, 2012. Published June 2008December 2012. Originally approved in 1997. Last previous edition approved in 20042008 asD6144 - 04.D6144 08. DOI
13、: 10.1520/D6144-08.10.1520/D6144-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from U.S.
14、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 and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previo
15、us 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 the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Chang
16、es section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1are measured and converted to concentrations via an external standard methodology. Purity by GC (the AMS content) is calculatedby subtractin
17、g the sum of the impurities from 100.00. Results are reported in weight percent.5. Significance and Use5.1 This test method is suitable for setting specifications on the materials referenced in 1.2 and for use as an internal qualitycontrol tool where AMS is produced or is used in a manufacturing pro
18、cess. It may also be used in development or research workinvolving AMS.5.2 This test method is useful in determining the purity of AMS with normal impurities present. If extremely high boiling orunusual impurities are present in the AMS, this test method would not necessarily detect them and the pur
19、ity calculation wouldbe erroneous.6. Apparatus6.1 Gas ChromatographAny instrument having a flame ionization detector that can be operated at the conditions given inTable 2. The system should have sufficient sensitivity to obtain a minimum peak height response for 10 mg/kg acetophenone oftwice the he
20、ight of the signal background noise.TABLE 1 Summary of Precision Data (mg/kg)Compound Repeatability (r) Reproducibility (R) Range StudiedCompound Repeatability Reproducibility Range StudiedAcetone 1.61 + 0.035*Acetone 0.47 + 1.10*Acetone 0.5 26Cumene 0.46 + 0.031*Cumene 7.88 + 0.19*Cumene 45 290nPro
21、pylbenzene (NPB) 2.11 + 0.03*NPB 7.81 + 0.37*NPB 55 195Phenol 1.84 3.65 + 0.58*Phenol 1 40tertButylbenzene (TBB) 1.22 + 0.035*TBB 3.63 + 0.087*TBB 150 650secButylbenzene (SBB) 4.23 + 0.019*SBB 21.60 + 0.25*SBB 200 765mCymene 0.31 + 0.035*mCymene 2.34 + 0.35*mCymene 2 50oCymene 1.63 8.00 29 31pCymene
22、 5.12 15.79 10 18cis-2-Phenyl-2-Butene (CPB) 0.17 + 0.030*CPB 5.39 + 0.11*CPB 50 225trans-2-Phenyl-2-Butene (TPB) 1.57 0.54 + 0.20*TPB 19 701-Phenyl-1-Butene (PB) 4.00 + 0.018*PB 0.17 + 0.19*PB 0.2 735Acetophenone (AP) 1.09 + 0.15*AP 1.17 + 0.63*AP 15 115para-tert-Butylcatechol (PTBC) 2.21 17.82 10
23、192-Methylbenzofuran (MBF) 0.33 + 0.76*MBF 0.75 + 0.60*MBF 1 22-Phenylpropion aldehyde (PPA) 0.59 + 0.11*PPA 0.29 + 0.23*PPA 1.5 15-Methylstyrene Oxide (AMSO) 4.61 6.51 + 0.23*AMSO 13 32DimethylBenzyl Alcohol (DMBA) 0.38 0.55 + 2.03*DMBA 0.1 1TABLE 2 Instrumental ParametersRecommended OperatingCondi
24、tionsDetector flame ionizationInjection Port capillary splitterColumn A:Tubing fused silicaStationary phase crosslinked methylsiliconeFilm thickness, m 1.0Length, m 60Diameter, mm 0.32Temperatures:Injector, C 250Detector, C 300Oven, C 85 hold for 13 minRamp 1 = 6C/min to 125C,hold for 2 minRamp 2 =
25、30C/min to 250C,hold for 7.5 minCarrier gas heliumFlow rate, mls/min 3Split ratio 60:1Sample size, l 1.0D6144 1226.2 ColumnsThe choice of column is based on resolution requirements. Any column may be used that is capable of resolvingall significant impurities from AMS. The column described in Table
26、2 has been used successfully. Unless the analyst can be sureof peak identity, for example by gas chromatography-mass spectrometry (GC-MS), the use of the column successfully and shallbe used as a referee in Table 2 is strongly recommended.cases of dispute.6.3 RecorderElectronic integration is recomm
27、ended.6.4 InjectorThe specimen must be precisely and repeatably injected into the gas chromatograph. An automatic sampleinjection device is highly recommended. Manual injection can be employed if the precision stated in Table 1 can be reliably andconsistently satisfied.7. Reagents and Materials7.1 P
28、urity 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 on Analytical Reagents of the American Chemical Society, where suchspecifications are available.4 Other grades may be u
29、sed, 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 Carrier GasGas, Makeup, and Detector GasesHelium, hydrogen, nitrogen, or other carrier, makeup and detector gases99.999 % minimum purity. Oxy
30、gen in carrier gas less than 1 ppm, less than 0.5 ppm is preferred. Purify carrier, makeup, anddetector gases to remove oxygen, water, and hydrocarbons.7.3 Compressed AirPurify air to remove water and hydrocarbons. Air for a FID should contain less than 0.1 ppm THC.7.4 HydrogenPure Compounds for Cal
31、ibartion99.999 % minimum purity.The purity of all reagents should be 99.9 % orgreater. If the purity is less than 99 %, the concentration and identification of impurities must be known so that the compositionof the standard can be adjusted for the presence of the impurities.8. Hazards8.1 Consult cur
32、rent OSHA regulations, suppliers Material Safety Data Sheets, and local regulations for all materials used inthis test method.9. Sampling and Handling9.1 Sample the material in accordance with Practice D3437.10. Preparation of Apparatus10.1 Follow manufacturers instructions for mounting and conditio
33、ning the column into the chromatograph and adjusting theinstrument to the conditions described in Table 2 allowing sufficient time for the equipment to reach equilibrium. See PracticeE1510 for more information on column installation. See Practice E355 for additional information on gas chromatography
34、 practicesand terminology.11. Calibration11.1 Prepare a synthetic mixture of high purity AMS containing impurities at concentrations representative of those expectedin the samples to be analyzed in accordance with Practice D4307. The weight of each hydrocarbon impurity must be measuredto the nearest
35、 0.1 mg. Because the availability of stock AMS with a purity higher than 99.80 % is problematic, the method ofstandard additions may be required for impurities such as tert-butylbenzene and n-proplybenzene, as well as for a number of theother impurities listed in 1.2 that are commonly present. In ad
36、dition, nearly all commercially available AMS is stabilized with 10to 30 mg/kg of para-tertiary-butylcatechol, requiring a standard addition methodology for this component as well unless AMS canbe obtained safely and directly from the point of manufacture.11.2 Inject the resulting solution from 11.1
37、 into the gas chromatograph, collect and process the data. A typical chromatogramis illustrated in Fig. 1 based on the conditions listed in Table 2.11.3 Determine the response factor for each impurity in the calibration mixture as follows:Rfi5Ci/Ai (1)where:where:Rfi = response factor for impurity i
38、,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 Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharma
39、copeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D6144 123FIG. 1 Typical AMS Chromagram, AMS MethodD6144 124Ci = concentration of impurity i in the calibration mixture, andAi = peak area of impurity i.11.4 Initially analyze the calibration solution a minimum of
40、 three times and calculate an average Rfi. Subsequent calibrationsmay be a single analysis as long as the Rfis for all components of interest are within 65 % of the initial validation Rfis. A “rolling”average as defined by most modern chromatographic software may also be used. The Rfi for tert-butyl
41、benzene is used for thequantification of unknown impurities.12. Procedure12.1 Inject into the gas chromatograph an appropriate amount of sample as previously determined according to 6.1 and start theanalysis.12.2 Obtain a chromatogram and peak integration report. Fig. 1 illustrates a typical analysi
42、s of AMS using the column andconditions outlined in Table 2.13. Calculations13.1 Of the impurities identified in AMS, only the butenylbenzene isomers are not available commercially. However, puresamples of these isomers can be prepared, and testing has shown that all three isomers have the same resp
43、onse factor 65 %, andthat it is equivalent to that for tert-butylbenzene 65 %.513.2 Calculate the concentration of each impurity as follows:Ci 5Ai! Rfi! (2)where:where:Ci = concentration of component i, in mg/kg,Ai = peak area of component i, andRfi = response factor for component i.13.3 Calculate t
44、he total concentration of all impurities in wt. % as follows:Ct5 Ci/10000 (3)where:where:Ct = total concentration of all impurities.13.4 Calculate the purity of AMS as follows:AMS, weight percent5100.002Ct (4)14. Report14.1 Report the individual impurities to the nearest 0.1 mg/kg.14.2 Report the pu
45、rity of AMS to the nearest 0.01 wt. %.15. Precision and Bias515.1 The following criteria in Table 1should be used to judge the acceptability at the 95 % probability level of the of resultsobtained by this test method. The method (95 % confidence level). The precision criteria were derived from an in
46、terlaboratorystudy between ILS that was conducted using the conditions listed in Table 1 which included five laboratories onanalyzing sixsamples run in triplicate by the same operator on the same day. The resultsPractice E691 were derived using the protocol set forthin Practicewas followed for the d
47、esign and analysis of the E691data; the details are given in ASTM Research Report RR:D16-1022.15.2 RepeatabilityResults in the same laboratory should not be considered suspect unless they differ by more than the amountscalculated from the appropriate equations in Table 1. Results differing by less t
48、han “r” have a 95 % probability of being correct.15.3 ReproducibilityResults submitted by two laboratories should not be considered suspect unless they differ by more thanthe amounts calculated from the appropriate equations in Table 1. Results differing by less than “R” have a 95 % probability ofbe
49、ing correct.15.4 BiasSince there is no accepted reference material suitable for determining the bias in this test method for measuring theseimpurities, bias has not been determined.5 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D16-1022.D6144 12516. Quality Guidelines16.1 Refer to GuideLaboratories shall have D6809 for suggested QA/QC activities that can be used as a part of this method.It is recommended that the operator of thi
