1、Designation: D4275 09D4275 17Standard Test Method forDetermination of Butylated Hydroxy Toluene (BHT) inPolymers of Ethylene and EthyleneVinyl Acetate (EVA)Copolymers Byby Gas Chromatography1This standard is issued under the fixed designation D4275; the number immediately following the designation i
2、ndicates the year oforiginal 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 Scope*1.1 This test method describes a pro
3、cedure for the determination of butylated hydroxy toluene (BHT) (2,6-di-t-butyl-4-methyl-hydroxybenzene) in polymers of ethylene and ethylene-vinyl acetate (EVA) copolymers by solvent extraction followedby gas chromatographic analysis. Detection of the compound is achieved by flame ionization, and q
4、uantitative analysis is obtainedby use of internal or external standards, as described in Practices E260, E355, and E594.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of
5、 the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 9.NOTE 1There
6、 is no known ISO equivalent for this test method.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD4968 Practice for Annual Review of Test Methods and Specifications for PlasticsD7210 Practice for Extraction of Additives in Polyolefin PlasticsE260 Practice for Packed C
7、olumn Gas ChromatographyE355 Practice for Gas Chromatography Terms and RelationshipsE594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid ChromatographyE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodIEEE/ASTM SI-10 P
8、ractice for Use of the International System of Units (SI) (the Modernized Metric System)3. Terminology3.1 DefinitionsUnits and symbols used in this test method are those recommended in Practice IEEE/ASTM SI-10.Chromatographic terms and relationships are as described in Practice E355.3.2 Abbreviation
9、s:3.2.1 BHTButylated hydroxy toluene (2,6-di-tert-butyl-4-methyl-hydroxybenzene).3.2.2 MMMethyl myristate.3.2.3 EVAEthylene-vinyl acetate copolymers.3.2.4 LDPELow-density polyethylene.3.2.5 HDPEHigh-density polyethylene.4. Summary of Test Method4.1 The BHT from a finely ground polymer sample is extr
10、acted by shaking or refluxing with cyclohexane or isopropanol. Aknown volume of this extract is injected into a gas chromatographic column packed with a liquid-coated solid support. Passing1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility
11、 of Subcommittee D20.70 on Analytical Methods.Current edition approved Aug. 1, 2009March 1, 2017. Published August 2009March 2017. Originally approved in 1983. Last previous edition approved in 20022009 asD4275 - 02.D4275 - 09. DOI: 10.1520/D4275-09.10.1520/D4275-17.2 For referencedASTM standards, v
12、isit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM stan
13、dard 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 the current versionof the standard as published by AST
14、M 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 States1through this column in a stream of carrier gas, BHT is separated from the ext
15、raction solvent and other components. Responses ofBHT and any internal standard are measured by a flame ionization detector. This signal is recorded to indicate the relativeconcentration and retention time of BHT.5. Significance and Use5.1 Separation and identification of stabilizers used in the man
16、ufacture of polyethylene are necessary in order to correlateperformance properties with polymer composition.5.2 The BHT extraction procedure is made effective by the insolubility of the polymer sample in solvents generally used forgas chromatographic analysis.6. Interferences6.1 Any material eluting
17、 at or near the BHT or MM retention times will cause erroneous results. Prior to extraction, solventblanks shall be analyzed to confirm the absence of interfering peaks.7. Apparatus7.1 Reflux Extraction, consisting of 250-mL round-bottom flask with condenser and heating mantle to fit.7.2 Wiley Mill,
18、 with 10 and 20-mesh screens.7.3 Wrist-Action Shaker.7.4 Gas Chromatograph, equipped with a flame ionization detector.7.5 Chromatographic Column, 3.2-mm outside diameter times 1.8 m packed with 20 % UCW-98 on 80/100 mesh ChromosorbP, a similar packed column, or an equivalent capillary column, such a
19、s a HP-1 or DB-1.7.6 Integrator, capable of measuring the net peak area on the back side of a solvent peak.7.7 Gas Chromatographic Syringe, 10 L.7.8 Analytical Balance, capable of weighing to 60.0001 g.7.9 Pressure Regulators, for all required gas cylinders.7.10 Filter-Dried Assemblies, for each req
20、uired gas cylinder.7.11 Soap Film Flowmeter and Stopwatch, or other means of measuring gas flow rates.8. Reagents and Materials8.1 Cyclohexane, reagent grade.8.2 Isopropyl Alcohol, reagent grade.8.3 Methyl Myristate,399+ %, boiling point 323C (internal standard).8.4 Butylated Hydroxy Toluene, food g
21、rade (2,6-di-tert-butyl-4-methyl-hydroxybenzene).8.5 Hydrogen Cylinder, prepurified.8.6 Nitrogen Cylinder, prepurified, oxygen-free for carrier gas.NOTE 2Helium or hydrogen may also be used as the carrier gas.8.7 Air, breathing or water-pumped.9. Safety Precautions9.1 Cyclohexane and isopropyl alcoh
22、ol are flammable. This extraction procedure shouldshall be carried out in a fume hood.10. Preparation of Gas Chromatograph10.1 Install the chromatographic column and condition overnight at 200C with carrier gas flow rate of 35 mL/min. Do notconnect the exit end of the column to the detector during t
23、his conditioning period. Turn off hydrogen and air flows to the detectorwhile the column is disconnected.10.2 Connect the exit end of the column to the detector. Set optimum hydrogen and air flow rates for the detector as specifiedfor the chromatograph model in use, or as determined experimentally.3
24、 The sole source of supply of the methyl myristate known to the committee at this time is Aldrich Chemical Co., P.O. Box 355, Milwaukee, WI 53201. If you are awareof alternative suppliers, please provide this information toASTM International Headquarters.Your comments will receive careful considerat
25、ion at a meeting of the responsibletechnical committee,1 which you may attend.D4275 17210.3 Set chromatograph temperatures as follows:10.3.1 Oven (chromatographic column), 160C.10.3.2 Injection block, 220C.10.3.3 Detector block, 240C.11. Calibration by Internal Standard11.1 Weigh a syringe containin
26、g approximately 80 mg of methyl myristate.11.2 Transfer syringe contents to a 2-L volumetric flask and immediately reweigh the syringe (60.1 mg).11.3 Dilute to volume with extraction solvent (cyclohexane or isopropyl alcohol) and store in a tightly stoppered flask.11.4 Weigh and transfer 20 6 0.1 mg
27、 of BHT into a 500-mL volumetric flask.11.5 Dissolve BHT in the internal standard solution in accordance with 11.3 and dilute to volume using this same solution.11.6 Inject 2 L of this calibration mixture into the gas chromatograph equilibrated to the conditions of 10.3.11.7 Chromatograph BHT and MM
28、 and record their respective peak areas using an integrator.NOTE 3The BHT and methyl myristate peak elute at approximately 3.5 and 8 min, respectively.11.8 Using BHT and MM areas from 11.7, determine the relative response factor (Rf) as follows:Rf 5concentration mg/L! BHT3area MMconcentration mg/L!
29、MM3area BHT (1)11.9 Average response factors for five replicate injections of the calibration mixture.12. Calibration by External Standard12.1 Weigh 100 6 1 mg of BHT into a 200-mL volumetric flask.12.2 Dissolve in the selected extraction solvent (cyclohexane or isopropyl alcohol) and dilute to volu
30、me.12.3 Pipet 2.0, 4.0, 6.0, and 8.0 mL of the above stock solution into a series of 100-mL volumetric flasks and dilute to volumewith the appropriate solvent.12.4 Inject 2 L of each dilute standard into the gas chromatograph equilibrated to the conditions of 10.3.12.5 Measure the BHT peak height (m
31、m) and multiply by the attenuation and range to obtain the total peak height area for eachstandard. Integrated peak areas can also be used.12.6 Repeat the injection of each standard and average the total peak height (or area) peak area results for duplicate injections.12.7 Plot the total peak height
32、 (or area) peak area on the y-axis versus concentration (g/mL) for each standard on the x-axis.The slope of this curve is proportional to the flame response for BHT.NOTE 4Chromatographic response for BHT should be determined by each analyst every day. Observe that the curve intercept should be zero.
33、13. Sample Preparation13.1 Grind HDPE, LDPE, and EVA samples containing less than 10 % vinyl acetate to 20-mesh size.13.2 Grind samples containing greater than 20 % vinyl acetate to 10-mesh size.14. Procedure14.1 Isopropyl Alcohol Extraction:14.1.1 For analysis of LDPE or EVA, weigh 3 6 0.001 g of g
34、round sample into a 250-mL round-bottom flask.14.1.2 Pipet 25.0 mL of isopropyl alcohol internal standard solution prepared in 11.3 into the flask and connect it to thecondenser.NOTE 5With external standard calibration, substitute the appropriate solvent for internal standard solution in 11.3 in the
35、 above procedure.14.1.3 Reflux 2 h and cool to room temperature before removing the flask from the condenser.14.2 Cyclohexane Extraction:14.2.1 For HDPE, repeat 14.1.1 14.1.3, substituting cyclohexane for isopropyl alcohol.NOTE 6IPA can be used for HDPE extractions, but the recovery was found to be
36、10 % lower than with cyclohexane.14.2.2 For LDPE or EVA, weigh 3 6 0.001 g of ground sample into a 250-mL round-bottom flask. Pipet 25.0 mL ofcyclohexane internal standard solution prepared in 11.3 into the flask and insert the stopper. Shake at room temperature for 2 hon a wrist-action shaker.14.3
37、Extract AnalysisInject 2 L of sample extract into the gas chromatograph equilibrated to conditions of 10.3. Measureareas of BHT and methyl myristate peaks (if using internal standard calibration) and record as ABHT and AMM, respectively.D4275 173NOTE 7Alternative extraction methods may be used in ac
38、cordance with Practice D7210.15. Calculation15.1 Internal StandardUsing the response factor (Rf) determined in 11.8 and area responses from chromatography of sampleextracts, calculate the BHT content of each sample from the following equation:ppm BHT5ABHT!Rf!C!V!AMM! W!(2)where:ABHT = area of BHT pe
39、ak in sample chromatogram,AMM = area of methyl myristate peak in sample chromatogram,Rf = response factor from 11.8,C = concentration of MM in the internal solution, mg/L,V = volume of internal standard solution used for extraction, mL, andW = weight of sample extracted, g.15.2 External StandardUsin
40、g the calibration slope from 12.7, calculate the BHT content of each sample from the followingequation:BHT in ppm by weight! 5 BVSW (3)where:B = BHT area or peak height from sample chromatogram,B = BHT area from sample chromatogram,V = volume of extraction solution, mL,W = weight of sample extracted
41、, g, andS = slope of calibration curve (from 12.7).16. Report16.1 Report the following information:16.1.1 Sample identification,16.1.2 Sample preparation method used,16.1.3 Gas chromatography analysis method used, including type of calibration, and16.1.4 Concentration of BHT in the polymer, ppm.17.
42、Precision and Bias17.1 PrecisionTable 1 is based on a round robin conducted in accordance with Practice E691 involving two materials testedby five laboratories. For each material, all samples were prepared at one source, but specimens were prepared at the laboratoriesthat tested them. Each test resu
43、lt was an average of two individual determinations. Each laboratory obtained two test results foreach sample.17.2 Samples included HDPE and EVA (0 to 19 % VA) with BHT levels of 70 to 930 g/g.17.3 For HDPE containing 150 to 350-g/g ppm BHT, values determined using cyclohexane extraction averaged 10
44、% higherthan those derived from isopropanol extraction.17.4 BiasThere are no recognized standards by which to estimate the bias of this test method.NOTE 8Caution should be exercised with the between-laboratory results since fewer than six laboratories participated in the round-robin study.TABLE 1 Su
45、mmary of Method PrecisionExtraction Solvent Expressed as Percent of the AverageCV %rA CV %rB CV %RCIsopropanolCyclohexane2.72.95.04.97.47.4ACV %r = within laboratory coefficient of variation between a pair of replicates(expressed in percent).BCV %r = within laboratory coefficient of variation of the
46、 average of two analyseson different days (expressed in percent).CCV %R = between laboratory coefficient of variation of the average (expressed inpercent).D4275 17418. Keywords18.1 butylated hydroxy toluene; BHT; ethylene-vinyl acetate; gas chromatography; polyethyleneSUMMARY OF CHANGESCommittee D20
47、 has identified the location of selected changes to this standard since the last issue (D4275 - 09)that may impact the use of this standard. (March 1, 2017)(1) Removed permissive language.(2) All measurements listed as peak areas.ASTM International takes no position respecting the validity of any pa
48、tent 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 responsibility.This standard is subject to revisio
49、n 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 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 Standar
