1、Designation: D6144 13D6144 17Standard 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 yea
2、r 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. Calibrati
3、on 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, acetop
4、henone, 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 ofAMS.The method has also been found applicable for the determination of para-tertiary-butylcatechol typically added as a stabilizer toAMS. The impur
5、ities in AMS can be analyzed over a range of 5 to 800 mg/kg by this method. (See Table 1.) The limit ofdetectionquantitation for these impurities is typically in the range of 5 to 10these impurities averages 4 mg/kg, while the limit ofdetection averages 1.2 mg/kg. (See Table 1.)1.3 In determining th
6、e conformance of the test results using this method to applicable specifications, results shall be roundedoff in accordance with the rounding-off method of Practice E29.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 T
7、his standard does not purport to address all the safety concerns, if any, associated 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 stat
8、ements, see Section 8.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Te
9、chnical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3437 Practice for Sampling and Handling Liquid Cyclic ProductsD4307 Practice for Preparation of Liquid Blends for Use as Analytical StandardsD4790 Terminology of Aromatic Hydrocarbons and Related ChemicalsD6809 Gui
10、de for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE355 Practice for Gas Chromatography Terms and RelationshipsE691 Practice for Conducting an Interl
11、aboratory Study to Determine the Precision of a Test MethodE1510 Practice for Installing Fused Silica Open 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 use
12、d in this test method.1 This test method is under 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
13、 approved June 1, 2013June 1, 2017. Published June 2013June 2017. Originally approved in 1997. Last previous edition approved in 20122013 as D6144 12.13. DOI: 10.1520/D6144-13.10.1520/D6144-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at ser
14、viceastm.org. For Annual Book of ASTM Standardsvolume 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.gp
15、o.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 previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult pri
16、or 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 Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194
17、28-2959. United States14. Summary of Test Method4.1 AMS (-methylstyrene) is analyzed by a gas chromatograph (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 impuritiesare meas
18、ured and converted to concentrations via an external standard methodology. Purity by GC (theAMS content) is calculatedby subtracting 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
19、 materials referenced in 1.2 and for use as an internal qualitycontrol tool where AMS is produced or is used in a manufacturing process. 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
20、 extremely high boiling orunusual impurities are present in the AMS, this test method would not necessarily detect them and the purity calculation wouldbe erroneous.6. Apparatus6.1 Gas ChromatographAny instrument having a flame ionization detector that can be operated at the conditions given inTable
21、 2. The system should have sufficient sensitivity to obtain a minimum peak height response for 10 mg/kg acetophenone ofTABLE 1 Summary of Precision Data (mg/kg)Compound Repeatability (r) Reproducibility (R) Range StudiedAcetone 1.61 + 0.035*Acetone 0.47 + 1.10*Acetone 0.5 26Cumene 0.46 + 0.031*Cumen
22、e 7.88 + 0.19*Cumene 45 290nPropylbenzene (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 5
23、0oCymene 1.63 8.00 29 31pCymene 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-Buty
24、lcatechol (PTBC) 2.21 17.82 10 192-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 Recommended Operat
25、ing ConditionsDetector 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 min
26、Ramp 2 = 30C/min to 250C,hold for 7.5 minCarrier gas heliumFlow rate, mls/min 3Split ratio 60:1Sample size, l 1.0D6144 172twice the height of the signal background noise.6.2 ColumnsThe choice of column is based on resolution requirements.Any column may be used that is capable of resolvingall signifi
27、cant impurities from AMS. The column described in Table 2 has been used successfully and shall be used as a refereein cases of dispute.6.3 RecorderElectronic integration is recommended.Chromatographic data systems are preferred but electronic integrationmay be used if the user can demonstrate that t
28、he results are consistent with the precision statement. Recorders are not consideredadequate for meeting the precision requirements of this standard.6.4 InjectorThe specimen must be precisely and repeatably injected into the gas chromatograph. An automatic sampleinjection device is highly recommende
29、d. Manual injection can be employed if the precision stated in Table 1 can be reliably andconsistently satisfied.7. Reagents 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 specifi
30、cation of the Committee onAnalytical Reagents of theAmerican Chemical Society, where suchspecifications are available.4 Other 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
31、Carrier Gas, Makeup, and Detector GasesHelium, hydrogen, nitrogen, or other carrier, makeup and detector gases99.999 % minimum purity. Oxygen 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 Compre
32、ssed AirPurify air to remove water and hydrocarbons. Air for a FID should contain less than 0.1 ppm THC.7.4 Pure Compounds for CalibartionThe purity of all reagents should be 99.9 % or greater. If the purity is less than 99 %,the concentration and identification of impurities must be known so that t
33、he composition of the standard can be adjusted for thepresence of the impurities.8. Hazards8.1 Consult current OSHA regulations, suppliers Material suppliersSafety Data Sheets, and local regulations for all materialsused in this test method.9. Sampling and Handling9.1 Sample the material in accordan
34、ce with Practice D3437.10. Preparation of Apparatus10.1 Follow manufacturers instructions for mounting and conditioning 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 PracticeE1
35、510 for more information on column installation. See Practice E355 for additional information on gas chromatography 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
36、 analyzed in accordance with Practice D4307. The weight of each hydrocarbon impurity must be measuredto the nearest 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
37、 and n-proplybenzene, as well as for a number of theother impurities listed in 1.2 that are commonly present. In addition, 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 unles
38、sAMS canbe obtained safely and directly from the point of manufacture.11.2 Inject the resulting solution from 11.1 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
39、 each impurity in the calibration mixture as follows:Rfi5Ci/Ai (1)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 Chemi
40、cals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D6144 173FIG. 1 Typical AMS Chromagram, AMS MethodD6144 174where:Rfi = response factor for impurity i,Ci = concentration of impurity i in the calib
41、ration mixture, andAi = peak area of impurity i.11.4 Initially analyze the calibration solution a minimum of 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“r
42、olling”average as defined by most modern chromatographic software may also be used. The Rfi for tert-butylbenzene is used for thequantification of unknown impurities.12. Procedure12.1 Inject into the gas chromatograph an appropriate amount of sample sufficient to satisfy the sensitivity conditions d
43、etailedin 6.1 and start the analysis.12.2 Obtain a chromatogram and peak integration report. Fig. 1 illustrates a typical analysis 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 com
44、mercially. However, puresamples of these isomers can be prepared, and testing has shown that all three isomers have the same response 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:Ci = conc
45、entration of component i, in mg/kg,Ai = peak area of component i, andRfi = response factor for component i.13.3 Calculate the total concentration of all impurities in wt. % as follows:Ct5Ci/10000 (3)where:Ct = total concentration of all impurities.13.4 Calculate the purity of AMS as follows:AMS,weig
46、ht percent5100.002Ct (4)14. Report14.1 Report the individual impurities to the nearest 0.1 mg/kg.14.2 Report numbers below the LOD as 1 mg/kg.14.3 Report the purity of AMS to the nearest 0.01 wt. %.15. Precision and Bias515.1 The following criteria should be used to judge the acceptability of result
47、s obtained by this test method (95 % confidencelevel). The precision criteria were derived from an ILS that was conducted using the conditions listed in Table 1 which includedfive laboratories analyzing six samples in triplicate by the same operator on the same day. Practice E691 was followed for th
48、edesign and analysis of the data; 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 tha
49、n “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 ofbeing 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 fil
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