1、Designation: F 1519 98 (Reapproved 2008)Standard Test Method forQualitative Analysis of Volatile Extractables in MicrowaveSusceptors Used to Heat Food Products1This standard is issued under the fixed designation F 1519; the number immediately following the designation indicates the year oforiginal a
2、doption 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. Scope1.1 This test method is applicable to complete microwavesusceptors.1.2 Th
3、is test method covers a procedure for identifyingvolatile extractables which are released when a microwavesusceptor sample is tested under simulated end use conditions.The extractables are identified using gas chromatography/massspectrometry (GC/MS).1.3 This test method was evaluated for the identif
4、ication ofa variety of volatile extractables at a level of 0.010 g/in.2ofsusceptor surface. For extractables not evaluated, the analystshould perform studies to determine the level of extractable atwhich identification is achievable.1.4 The analyst is encouraged to run known volatile extract-ables a
5、nd/or incorporate techniques such as gaschromatography/high resolution mass spectrometry (GC/HRMS), gas chromatography/infrared spectroscopy (GC/IR)or other techniques to aid in verifying the identity of oridentifying unknown volatile extractables. The analyst is re-ferred to Practice E 260 for addi
6、tional guidance.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 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 t
7、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 260 Practice for Packed Column Gas ChromatographyF 874 Test Method for Temperature Measurement and Pro-filing for Microwave Suscep
8、torsF 1308 Test Method for Quantitating Volatile Extractablesin Microwave Susceptors Used for Food ProductsF 1317 Test Method for Calibration of Microwave Ovens3. Terminology3.1 Definitions:3.1.1 diffusion trappingthe collection of volatile extract-ables on an adsorbent by means of the mass diffusio
9、n of thevolatile extractables (1).33.1.2 microwave susceptorspackaging material which,when placed in a microwave field interacts with the field andprovides heating for the food products the package contains.3.1.3 volatile extractablesthose compounds that give 50 % recovery in spike and recovery stud
10、ies using the appli-cable volatile extractables method. Extractability does notnecessarily imply migration of the extractable species to thefood product being heated on the susceptor.4. Summary of Test Method4.1 The volatile extractables are released from the susceptorwhen it has been heated to its
11、end use heating conditions(temperature and heating time) using a thermostatically con-trolled oil bath or calibrated microwave oven. The releasedvolatile extractables are concentrated by diffusion trapping onan adsorbent. After adsorption is complete, the adsorbent isheated to desorb the volatile ex
12、tractables onto a gas chromato-graphic column (Refs 17). The volatile extractables are thenseparated using a gas chromatograph and detected by a massspectrometer. The volatile extractable identifications are con-firmed by comparing their retention times and mass spectra toreference compounds under i
13、dentical GC/MS conditions.5. Significance and Use5.1 This test method is intended to identify volatile extract-ables that may be emitted from microwave susceptor materialduring use. It may be a useful procedure to assist in minimizing1This test method is under the jurisdiction of ASTM Committee F02
14、on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition approved Oct. 1, 2008. Published November 2008. Originallyapproved in 1994. Last previous edition approved in 2003 as F 1519 98(2003).2For referenced ASTM standards, visi
15、t the ASTM website, 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.3The boldface numbers in parentheses refer to a list of references at the end ofthis test method.
16、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the amount and type of volatile extractables produced. Thesusceptor design, materials used or manufacturing processesinvolved can be evaluated.6. Interferences6.1 Gas Chromatography/Mas
17、s SpectrometryThe GCconditions or column given may not exhibit sufficient resolu-tion to identify all the volatile extractables. Alternate tech-niques should be used to identify the unresolved volatileextractables such as alternate GC conditions, an alternate GCcolumn, GC/HRMS, and/or GC/IR. The ret
18、ention time andmass spectrum or infrared spectrum of the volatile extractableshould be verified with a reference standard.6.2 Apparatus and MaterialsMethod interferences maybe caused by contamination from vials, septa, syringes, etc.,leading to misinterpretation of results at trace levels. All of th
19、ematerials must be routinely demonstrated to be free fromcontamination under conditions of the analysis by runningblanks.7. Apparatus and Reagents7.1 Sample CutterNo. 14 cork borer.7.2 GlasswareWash all glassware thoroughly and dry in a125C air oven for a minimum of 4 h prior to using. Use nosolvent
20、s.7.2.1 Vials40 mL.7.2.2 Culture Tubes10by75mm.7.3 Vial CapsScrew caps for 7.2.1 vials.7.4 Vial SeptaPolytetrafluoroethylene PTFE faced siliconbacked septa, 22 mm diameter. Place septa into a vacuum ovenat 135C for 16 h prior to using.7.5 Volatile AdsorbentRefer to manufacturers literatureregarding
21、physical, chemical, absorptive and desorptive char-acteristics of adsorbent.7.5.1 AdsorbentTenax TA, 35/60 mesh.7.5.2 ConditioningPlug one end of a 14 cm long, 6.35outside diameter by 5.3 mm inside diameter tube, premiumgrade 304 stainless steel with a plug of silanized glass wool.Fill tube with ads
22、orbent, and plug other end with silanizedglass wool. Connect the tube to the injection port outlet of theGC, set the UHP helium flow to 30 mL/min and conditionadsorbent using the following program.Injection temperature 250CTemperature 1 70CTime 1 30 minRate 10C/minTemperature 2 250CTime 2 60 min7.5.
23、3 StorageCap both ends of the tube after it cools,move to a chemical free area, uncap one end, remove glasswool, tap tube to transfer adsorbent to 40 mL glass vial, purgevial with UHP helium or argon for 1 min and seal with aconditioned PTFE/silicon septa (PTFE surface toward adsor-bent). Exercise c
24、are in handling the adsorbent.7.5.4 BlanksThe adsorbent should be tested for contami-nation prior to being used.7.6 Oil BathCirculating bath capable of being heated to250 6 1C. Use silicone oil to heat vials.7.7 ThermometersCapable of measuring up to 250C.Calibrate thermometer with a NIST standardiz
25、ed thermometerto ensure its accuracy.7.8 GC/MS System:7.8.1 Gas Chromatographcapable of temperature pro-gramming. The inlet carrier gas line should be equipped with avalve capable of being completely opened and closed within1s.7.8.2 The injector should have a removable glass liner orinsert, having a
26、 volume of at least 300 L or 40 mg ofadsorbent. The injector should have a closure that allows theliner/insert to be inserted and the injector sealed within 5 s.Modification of the injector may be required (2) through (6).7.8.3 GC Column60M Stabilwax, 0.25 mm ID, 0.5 m df.7.8.4 Mass Spectrometer, ca
27、pable of scanning from 35 to300 amu every2sorless when mass spectral data are obtainedin the electronimpact ionization mode at a nominal electronenergy of 70 eV.7.8.5 Data SystemAn interfaced data system (DS) isrequired to acquire, store, reduce and output mass spectral data.The computer software mu
28、st allow searching of any GC/MSdata file for ions of a specific nominal mass and plot itsabundance versus time or scan number. This type of plot isdefined as an extracted ion current profile (EICP).7.9 Performance Volatile Standard for GC/MS System:7.9.1 Stock Volatile MixturePipet in accordance wit
29、hTable 1 the appropriate volume into a 100 mL volumetric flaskwhich has been half filled with hexane. After all compoundshave been added, fill to mark with hexane and mix well.Alternate compounds may be substituted. Refrigerate mixtureat 4C until needed.7.9.2 Performance Volatile StandardDilute stoc
30、k volatilemixture in step 7.9.1 1:1000 with hexane. Alternate dilutionsmay be made. Refrigerate standard at 4C until needed.7.10 Susceptor BlankObtain a representative sample ofsusceptor material to be tested. Bake in an air oven overnightat 105C to remove any volatile extractables present. Store in
31、a clean, sealed glass container (for example, desiccator) untilneeded.7.11 Heliumultra high purity (UHP).7.12 Calibrated Ovensee Test Method F 1317.TABLE 1 Stock Volatile MixturePreparation and CharacteristicIons, m/z, for Each VolatileCompound Volume Pipetted, mLACharacteristic Ions,m/z2-Methyl fur
32、an 1.7 82, 81, 53Benzene 1.7 78, 77, 52n-Propyl acetate 1.7 73, 43Trichloroethylene 1.0 130, 95Hexanal 2.0 56, 72, 82n-Butyl alcohol 2.0 43, 41, 56n-Butyl acrylate 1.7 55, 73, 85Dodecane 2.0 57, 71, 85Styrene 1.7 104, 103, 781,4-Dichlorobutane 1.5 55, 90N,N-Dimethylformamide 1.5 73, 44, 42Furfural 1
33、.5 95, 96Benzaldehyde 1.5 106, 105, 77Pentanoic acid 1.5 73, 602-(2-Butoxyethoxy)-ethanol1.5 45, 57, 75APipet into 100 mL volumetric flask which has been half filled with hexane.F 1519 98 (2008)28. Instrument Set-up8.1 Setup the GC/MS/DS to meet the following criteria.Alternate conditions can be use
34、d to resolve unidentified vola-tile compounds.Temperature 1 40CTime 1 3 minRate 10/minTemperature 2 210CTime 2 15 minCarrier gas flow 10 mL/min UHP heliumInjector Temperature 250CDetector electron multiplierInterface temperature 250CMass scanned 35250 amuIonization voltage 70 eV9. Daily GC/MS Perfor
35、mance Check9.1 Tune the mass spectrometer in accordance with theinstrument manufacturers procedure.9.2 Inject 1 L (approximately 14 to 18 ng of each volatileis injected) of the performance volatile standard (see 7.9.2)toverify chromatographic retention times and mass spectra pro-duced using conditio
36、ns in Section 8.Atypical chromatogram isshown in Fig. 1. As a minimum, the ions listed in Table 1should be present and in their expected ratios for each volatilelisted.9.3 Repeat 9.1 and 9.2 until these conditions are met prior torunning any sample.10. Sampling10.1 Microwave susceptor sample selecte
37、d for extractionshould be representative of the entire susceptor.10.2 Sample should be undamaged, that is, laminationintact, uncreased (unless this is its normal configuration), andunaltered.10.3 Carefully cut a 0.75-in. diameter circular portion fromthe susceptor using a cork borer. Carefully trim
38、away anyfrayed edges before extracting.11. Procedure11.1 Insert sample from 10.3 carefully into 40 mL vial.11.2 Place enough conditioned Tenax-GC (approximately avolume of 250 L or 40 mg) into a 10 by 75 mm culture tubeand place it in vial with susceptor.11.3 Immediately place septa over vial (PTFE
39、side towardsample) and cap.11.4 Place vial in an oil bath maintained at 218 6 1C (4256 2F) for 5 min. The oil bath temperature should be verifiedusing a calibrated thermometer. The temperature and time thesample is to be heated can be established using Test MethodsF 874 and F 1317. Alternately Test
40、Method F 1308 can be usedfor heating the susceptor.11.5 After heating, remove vial from oil bath and place in a35C oven for 16 hours.11.6 Pour the Tenex GC from the culture tube into a GCinjection port liner (see 7.8.2). A small funnel equipped with ashort piece of plastic tubing will aid in the tra
41、nsfer. Place a plugof silanized glass wool into the other end of the liner to retainthe Tenax.11.7 Turn off the carrier gas to the GC by using the inlettoggle valve.11.8 As quickly as possible, remove the cap from theinjector, place the liner in the injector port, replace the cap andturn the carrier
42、 flow on.11.9 Activate the GC program.11.10 Chromatograph the sample using the conditions givenin Section 8.11.11 A vial containing only the Tenax in a culture tubeshould be carried through the entire procedure to identifypotential artifactual peaks (7).12. Volatile Extractable Identification12.1 Fr
43、om the data obtained from Section 11, obtain a massspectrum for the volatile extractable of interest. A backgroundspectrum should be taken just before or after each volatileextractable elutes and subtracted from the volatile extractablespectrum to minimize mass spectral interferences.12.2 Using a su
44、itable reference library (8), search and findthe best match for the volatile extractable mass spectrum inquestion.12.2.1 Note that if several volatile extractables are presentin the sample and coelute, the resulting spectrum will representa composite. Alternate techniques may be needed to get asuita
45、ble mass spectrum of the volatile extractable of interest.Number Compound1 2-Methyl Furan2 Benzene3 n-Propyl Acetate4 Trichloroethylene5 Hexanal6 n-Butyl Alcohol7 n-Butyl Acrylate8 Dodecane9 Styrene10 1,4-Dichlorobutane11 N,N-Dimethylformamide12 Furfural13 Benzaldehyde14 Pentanoic Acid15 2-(2-Butoxy
46、ethoxy)-EthanolFIG. 1 Total Ion Chromatogram of Performance VolatileStandardF 1519 98 (2008)312.3 Using the same instrumental conditions that were usedto analyze the sample, collect the mass spectra of authenticreference compounds.12.4 Compare the mass spectra of the reference compoundsto the mass s
47、pectra of the unknown volatile extractables toconfirm the initial library search match.12.5 Compare the retention times of the authentic referencecompound and tentatively identified volatile extractable. If theretention time of the volatile extractable is within 6 1 % of theretention time of the ref
48、erence compound, the two compoundsmay be considered the same.13. Absorbent Efficiency13.1 Three independent laboratories ran a collaborativestudy using this method to determine the effectiveness of theabsorbent to adsorb and desorb volatile extractables reproduc-ibly and accurately.13.2 Each laborat
49、ory prepared aqueous standards of isopro-pyl alcohol, dibutyl ether, and toluene so that spiked susceptorsamples containing approximately 10 ng of each of thesecompounds could be analyzed.13.3 A 1 in.2sample of a vacuum dried, laminated product,was spiked with an aqueous standard on the paper side of thesusceptor, placed in a PTFE sealed 40 mL vial, and held for 16h at 35C for equilibrium prior to analyses.14. Reporting14.1 All reports should include test conditions, especiallythe susceptor maximum temperature and time held
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