ASTM F1308-98(2018)

Standard Test Method for Quantitating Volatile Extractables in Microwave Susceptors Used for Food Products

SIGNIFICANCE AND USE
5.1 This test method is intended to measure volatile extractables that may be emitted from a microwave susceptor material during use. It may be a useful procedure to assist in minimizing the amount of volatile extractables either through susceptor design or manufacturing processes.  
5.2 Modification of this procedure by utilizing appropriate qualitative GC detection such as a mass spectrometer in place of the flame ionization detector may provide identification of volatile extractables of unknown identity.
SCOPE
1.1 This test method covers complete microwave susceptors.  
1.2 This test method covers a procedure for quantitating volatile compounds whose identity has been established and which are evolved when a microwave susceptor sample is tested under simulated use conditions.  
1.3 This test method was collaboratively evaluated with a variety of volatile compounds (see statistical evaluation). For compounds other than those evaluated, the analyst should determine the sensitivity and reproducibility of the method by carrying out appropriate spike and recovery studies. The analyst is referred to Practice E260 for guidance.  
1.4 For purposes of verifying the identity of or identifying unknown volatile compounds, the analyst is encouraged to incorporate techniques such as gas chromatography/mass spectroscopy, gas chromatography/infrared spectroscopy, or other techniques in conjunction with this test method.  
1.5 A sensitivity level of approximately 0.025 μg/in.2 is achievable for the compounds studied in Table 1. Where other compounds are being quantitated and uncertainty exists over method sensitivity, the analyst is referred to Practice E260 for procedures on determining sensitivity of chromatographic methods.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific safety hazards warnings are given in 10.2, 11.1, and 11.6.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Aug-2018
• ICS: 67.250 - Materials and articles in contact with foodstuffs
• Technical Committee: F02 - Primary Barrier Packaging
• Drafting Committee: F02.15 - Chemical/Safety Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F1308 − 98 (Reapproved 2018)
Standard Test Method for
Quantitating Volatile Extractables in Microwave Susceptors
Used for Food Products
This standard is issued under the fixed designation F1308; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope mine the applicability of regulatory limitations prior to use.
Specific safety hazards warnings are given in 10.2, 11.1, and
1.1 This test method covers complete microwave suscep-
11.6.
tors.
1.8 This international standard was developed in accor-
1.2 This test method covers a procedure for quantitating
dance with internationally recognized principles on standard-
volatile compounds whose identity has been established and
ization established in the Decision on Principles for the
which are evolved when a microwave susceptor sample is
Development of International Standards, Guides and Recom-
tested under simulated use conditions.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.3 This test method was collaboratively evaluated with a
variety of volatile compounds (see statistical evaluation). For
2. Referenced Documents
compounds other than those evaluated, the analyst should
determine the sensitivity and reproducibility of the method by
2.1 ASTM Standards:
carrying out appropriate spike and recovery studies. The
E260 Practice for Packed Column Gas Chromatography
analyst is referred to Practice E260 for guidance.
F1317 Test Method for Calibration of Microwave Ovens
1.4 For purposes of verifying the identity of or identifying 2.2 TAPPI Standards:
unknown volatile compounds, the analyst is encouraged to
T 402 Standard conditioning and testing atmospheres for
incorporate techniques such as gas chromatography/mass paper, board, pulp handsheets, and related products
spectroscopy, gas chromatography/infrared spectroscopy, or
TIS 808 Equilibrium relative humidities over saturated salt
other techniques in conjunction with this test method. solutions
1.5 A sensitivity level of approximately 0.025 µg/in. is
3. Terminology
achievable for the compounds studied in Table 1. Where other
3.1 Definitions:
compounds are being quantitated and uncertainty exists over
method sensitivity, the analyst is referred to Practice E260 for 3.1.1 microwave susceptors—a packaging material which,
when placed in a microwave field, interacts with the field and
procedures on determining sensitivity of chromatographic
methods. provides heating for the products the package contains.
3.1.2 volatile extractables—those chemical species which
1.6 The values stated in SI units are to be regarded as
are released from the microwave susceptor and can be detected
standard. No other units of measurement are included in this
in the headspace under conditions simulating those under
standard.
which the susceptor is used. Extractability does not necessarily
1.7 This standard does not purport to address all of the
mean migration of the extractable species to the product being
safety concerns, if any, associated with its use. It is the
heated on the susceptors.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
4.1 Volatile extractables are determined by subjecting a
This test method is under the jurisdiction of ASTM Committee F02 on Primary
sample of the susceptor material to microwave heating, fol-
Barrier Packaging and is the direct responsibility of Subcommittee F02.15 on
lowed by headspace sampling and gas chromatography. Quali-
Chemical/Safety Properties.
tative analysis may be carried out on a gas chromatograph
Current edition approved Sept. 1, 2018. Published November 2018. Originally
approved in 1990. Last previous edition approved in 2014 as F1308 – 98(2014).
(GC) coupled to an appropriate detector capable of compound
DOI: 10.1520/F1308-98R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from Technical Association of the Pulp and Paper Industry (TAPPI),
the ASTM website. 15 Technology Parkway South, Norcross, GA 30092, http://www.tappi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1308 − 98 (2018)
TABLE 1 Analyte Recovery Without Microwaving
6.2 Apparatus—Because this test method is designed for
Within trace volatiles, and is highly sensitive, contaminants on vials,
Recovery Overall
A B
Compound ( n) Laboratory Note(s)
septa, syringes, etc. can lead to misinterpretation of results.
Mean, % Variability, %
Variability, %
Preparing apparatus properly and carrying out blank determi-
Benzene 5 97.7 7.8 9.0
nations as specified in the procedure is essential to minimize
2-Butoxy-ethanol 4 98.7 6.7 8.4 1
Dibutyl Ether 5 109.7 16.5 23.7 this possibility.
Dodecane 3 101.1 10.7 10.7 1, 2
2-Furfural 4 99.7 11.7 12.0 1
7. Apparatus and Reagents
Furan- 3 100.0 14.1 16.4 1, 3
2-Methanol
7.1 Microwave Oven—Calibrated, 7006 35 W, no turntable.
Isobutyl Alcohol 4 96.0 7.1 7.9 4
See Test Method F1317.
Methylene 5 103.5 16.7 22.6
Chloride
7.2 Humidity Chambers, operated at 50 % RH and 23°C.
2-Propanol 3 99.9 11.4 12.0 4
7.2.1 Requirements for constant temperature-humidity
Styrene 5 100.8 8.5 9.3
Toluene 4 102.7 9.9 10.9 4
chambers and equilibrium relative humidities over saturated
Overall 101.1 11.6 14.4
salt solutions are outlined in TAPPI Methods T 402-om-88, and
A
n = number of laboratories submitting data on compound.
TIS 808-03.
B
Notes: Collaborating laboratories provided the following reasons for not sub-
mitting data on a particular analyte: 7.3 Vials, headspace, 20 mL (actual volume 21.5 mL). To
1. The analyst felt interaction was occurring among various analytes and spent
ensure against extraneous peaks in the gas chromatographic
several days investigating. The laboratory manager refused to allow additional
traces, wash vials thoroughly and dry in a 125°C air oven for
time for collaborative study.
2. The analyst questioned the solubility of the analyte and did not add to the a minimum of 4 h before using.
spike mixture.
7.4 Vial Crimp Caps.
3. A fresh standard was not prepared fresh daily. This compound degrades
measurably in water in 24 h.
7.5 Septa, Polytetrafluoroethylene (PTFE)/silicone. To en-
4. The analyst experienced coelution of peaks under conditions of collaborative
study on his/her particular system.
sure that the septa are free of volatiles, cover the bottom of a
15-cm petri dish with septa, PTFE-polymer side up. Micro-
wave at full power for 10 min. Place microwaved septa into a
vacuum (greater than 29 in.) oven at 130°C for 16 h.
identification. Volatile extractables are quantitated by compari-
son with standards of known concentration. 7.6 Crimping Tool for vials.
7.7 Syringe, 2 mL, gas-tight with valve. Store syringe in
5. Significance and Use
90°C oven between uses.
5.1 This test method is intended to measure volatile extract-
7.8 Gas Chromatograph equipped as follows:
ables that may be emitted from a microwave susceptor material
7.8.1 FID Detector, compatible with capillary columns.
during use. It may be a useful procedure to assist in minimizing
7.8.2 Injector, split/splitless compatible with capillary col-
the amount of volatile extractables either through susceptor
umns.
design or manufacturing processes.
7.8.3 Automated Headspace Sampler, Optional.
5.2 Modification of this procedure by utilizing appropriate
7.8.4 Column, DB-5, 30 m, 0.25-mm inside diameter, 1-µm
qualitative GC detection such as a mass spectrometer in place
film thickness, or 0.32 mm. (A short piece of deactivated
of the flame ionization detector may provide identification of
0.25-mm fused silica column may be placed between the
volatile extractables of unknown identity.
injector and the column to serve as a guard column.)
7.8.5 Peak-Area Integration System compatible with GC
6. Interferences
system. Alternatively, a chart recorder and hand integration can
6.1 Gas Chromatography—Because of the potentially large be used.
number of chemical species that can be analyzed using this
7.9 Fluoroptic Thermometry System .
methodology, not all species will be resolved from one another
7.10 Temperature Probes, high temperature.
on a particular GC column under a given set of conditions.
Techniques available to the analyst to verify the identity of the
7.11 Beaker, 600 mL.
species being quantitated include retention time comparisons
7.12 Oven, hot air, set for 90°C.
using alternate GC conditions or using an alternate GC column
7.13 Stopwatch.
to verify identification. Good judgement of chromatographic
4,5,6
results is always important. Refer to Practice E260 for
7.14 4-Heptanone.
guidance.
7.15 Standard Solutions—Regular Method:
7.15.1 Internal Standard Solution (245 µg/mL
4-Heptanone)—To approximately 950 mL of distilled water in
McCown, S. M., and Radenheimer, P., “An Equilibrium Headspace Gas
Chromatographic Method for the Determination of Volatile Residues in Vegetable
Oils and Fats,” LC/GC, Vol 7, No. 11, 1989, pp. 918–924.
5 6
McNeal, T. P., and Breder, C. V., “Headspace Gas Chromatographic Determi- McNeal, T. P., and Breder, C. V., “Headspace Sampling and Gas-Solid
nation of Residual 1,3-Butadiene in Rubber-Modified Plastics and Its Migration Chromatographic Determination of Residual Acrylonitrile in Acrylonitrile Copoly-
from Plastic Containers Into Selected Foods,” Journal of the Association of mer Solutions,” Journal of the Association of Offıcial Analytical Chemists, Vol 64,
Analytical Chemists, Vol 70, No. 1, 1987, pp. 18–21. No. 2, 1981, pp. 270–275.
F1308 − 98 (2018)
a 1-L volumetric flask add 300 µL of 4-heptanone. Mix well 8.1.4 Place 250 mL of room-temperature distilled water into
and dilute to volume with water. a 600-mL beaker. Place the beaker in the center rear of the
microwave oven.
7.15.2 Standard Solution 1: (Prepare fresh daily.)—To ap-
2 2
proximately 475 mL of internal standard solution in a 500-mL 8.1.5 Cut a 10 by 65-mm (6.5-cm = 1-in. ) portion from
the susceptor sample to be tested. Insert carefully into the
volumetric flask, add 50 µL of each of the compounds to be
20-mL headspace vial.
quantitated. Mix well, and dilute to volume with internal
standard solution. If difficulty is experienced with dissolution 8.1.6 Using a 13-gage syringe needle, pierce a hole into a
of analyte, alternate standard solution procedure may over- headspace vial septum. Place the septum on the vial and crimp.
come this difficulty.
8.1.7 Insert one temperature probe (7.10) through the sep-
tum hole into the vial and manipulate it until it is in contact
7.15.3 Standard Solution 2—Repeat 7.14.2 using 25 µL of
with the active face of the susceptor material. Place the vial on
each compound.
its side in the center of microwave oven, crimp end toward
7.15.4 Standard Solution 3—Repeat 7.14.2 using 10 µL of
right of the oven, and susceptor with active face up.
each compound.
8.1.8 Microwave at full power, recording the probe
7.16 Standard Solutions—Alternate Method:
temperature, preferably at 5-s intervals, but at intervals not to
7.16.1 Alternate Internal Standard Solution (1225 µg/mL
exceed 15 s.
4-Heptanone)—To approximately 150 mL of helium-sparged
8.1.9 Plot the temperatures from 8.1.3 and 8.1.8 on the same
orthodichlorobenzene (ODCB) in a 200-mL volumetric flask
graph.
add 300 µL of 4-heptanone. Mix well and dilute to volume with
8.1.10 Compare the plots. If the trace from 8.1.8 closely
ODCB.
approximates or is slightly higher than the plot from 8.1.3 then
7.16.2 Alternate Standard Solution 1— To approximately 75
the test time will be equal to the maximum product cook time
mL of alternate internal standard solution in a 100-mL volu-
of the product in that oven. If the trace is substantially higher
metric flask, add 50 µL of each of the compounds to be
or lower than that of the susceptor with product, then adjust the
quantitated. Mix well, and dilute to volume with alternate
mass or surface area, or both, (by changing container size) of
internal standard solution.
the water (using a fresh sample of room temperature distilled
7.16.3 Alternate Standard Solution 2— Repeat 7.15.2 using
water) as necessary to achieve a similar profile. Record the
25 µL of each compound.
mass of water and type of container that gives the best
7.16.4 Alternate Standard Solution 3— Repeat 7.15.2 using
agreement between the test sample and the product temperature
10 µL of each compound.
profiles.
7.17 Susceptor Blank—Obtain a representative sample of
8.2 Set up the gas chromatographic system to meet the
susceptor material to be tested. Bake in an air oven overnight
following criteria.
at 100°C or higher to remove any volatile materials present.
8.2.1 Injector Temperature—250°C.
Store blank susceptor strips in humidity chamber 1 at 50 % RH
8.2.2 Detector Temperature—250°C.
and 23°C until equilibrium moisture content is reached. An
8.2.3 Column Temperature:
exposure time of 24 h is generally adequate for most paper-
8.2.3.1 Initial—40°C for 4 min.
based products. Strips should remain in the conditioning
8.2.3.2 Program—Adjust to give a retention window of:
environment until needed for analysis.
(1) At least 15 min for volatile compounds bracketed by
2-propanol and dichlorobenzene, retention time for 2-propanol
7.18 Syringe Needle, 13 gage.
of approximately 3 min and retention time for dichlorobenzene
7.19 Variable Voltage Transformer, Optional—This can oc-
of approximately 20 min.
casionally be used for minor adjustments to line voltage to
(2) Providing a separation of Di-n-butyl ether and styrene
bring power output of the microwave oven into the specified
of R = 0.5 or greater. For a 30-m by 0.25-mm column this is
range.
approximately 4°C/min with a nominal carrier flow of 1.5
mL/min.
8. Instrument Setup
8.2.4 Attenuation or sensitivity, or both, set to give an
8.1 Determine sample test conditions as follows:
internal standard peak height of 60 to 90% of full scale on
8.1.1 Set up microwave susceptor in the configuration of its recorder or integrator.
intended use, that is, a popcorn bag filled with popcorn, a pizza
disk with pizza on top, etc. 9. Sampling
8.1.2 Place temperature probes (7.10) on susceptor surface,
9.1 The sample of microwave susceptor selected for extrac-
disturbing the normal food
...

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. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: F1308 − 98 (Reapproved 2014) F1308 − 98 (Reapproved 2018)
Standard Test Method for
Quantitating Volatile Extractables in Microwave Susceptors
Used for Food Products
This standard is issued under the fixed designation F1308; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers complete microwave susceptors.
1.2 This test method covers a procedure for quantitating volatile compounds whose identity has been established and which are
evolved when a microwave susceptor sample is tested under simulated use conditions.
1.3 This test method was collaboratively evaluated with a variety of volatile compounds (see statistical evaluation). For
compounds other than those evaluated, the analyst should determine the sensitivity and reproducibility of the method by carrying
out appropriate spike and recovery studies. The analyst is referred to Practice E260 for guidance.
1.4 For purposes of verifying the identity of or identifying unknown volatile compounds, the analyst is encouraged to
incorporate techniques such as gas chromatography/mass spectroscopy, gas chromatography/infrared spectroscopy, or other
techniques in conjunction with this test method.
1.5 A sensitivity level of approximately 0.025 μg/in. is achievable for the compounds studied in Table 1. Where other
compounds are being quantitated and uncertainty exists over method sensitivity, the analyst is referred to Practice E260 for
procedures on determining sensitivity of chromatographic methods.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific safety hazards warnings are given in 10.2, 11.1, and 11.6.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E260 Practice for Packed Column Gas Chromatography
F1317 Test Method for Calibration of Microwave Ovens
2.2 TAPPI Standards:
T 402 Standard conditioning and testing atmospheres for paper, board, pulp handsheets, and related products
TIS 808 Equilibrium relative humidities over saturated salt solutions
3. Terminology
3.1 Definitions:
3.1.1 microwave susceptors—a packaging material which, when placed in a microwave field, interacts with the field and
provides heating for the products the package contains.
This test method is under the jurisdiction of ASTM Committee F02 on FlexiblePrimary Barrier Packaging and is the direct responsibility of Subcommittee F02.15 on
Chemical/Safety Properties.
Current edition approved April 1, 2014Sept. 1, 2018. Published April 2014November 2018. Originally approved in 1990. Last previous edition approved in 20082014 as
F1308 – 98(2008).(2014). DOI: 10.1520/F1308-98R14.10.1520/F1308-98R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Technical Association of the Pulp and Paper Industry (TAPPI), 15 Technology Parkway South, Norcross, GA 30092, http://www.tappi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1308 − 98 (2018)
TABLE 1 Analyte Recovery Without Microwaving
Within
Recovery Overall
A B
Compound ( n) Laboratory Note(s)
Mean, % Variability, %
Variability, %
Benzene 5 97.7 7.8 9.0
2-Butoxy-ethanol 4 98.7 6.7 8.4 1
Dibutyl Ether 5 109.7 16.5 23.7
Dodecane 3 101.1 10.7 10.7 1, 2
2-Furfural 4 99.7 11.7 12.0 1
Furan- 3 100.0 14.1 16.4 1, 3
2-Methanol
Isobutyl Alcohol 4 96.0 7.1 7.9 4
Methylene 5 103.5 16.7 22.6
Chloride
2-Propanol 3 99.9 11.4 12.0 4
Styrene 5 100.8 8.5 9.3
Toluene 4 102.7 9.9 10.9 4
Overall 101.1 11.6 14.4
A
n = number of laboratories submitting data on compound.
B
Notes: Collaborating laboratories provided the following reasons for not sub-
mitting data on a particular analyte:
1. The analyst felt interaction was occurring among various analytes and spent
several days investigating. The laboratory manager refused to allow additional
time for collaborative study.
2. The analyst questioned the solubility of the analyte and did not add to the
spike mixture.
3. A fresh standard was not prepared fresh daily. This compound degrades
measurably in water in 24 h.
4. The analyst experienced coelution of peaks under conditions of collaborative
study on his/her particular system.
3.1.2 volatile extractables—those chemical species which are released from the microwave susceptor and can be detected in the
headspace under conditions simulating those under which the susceptor is used. Extractability does not necessarily mean migration
of the extractable species to the product being heated on the susceptors.
4. Summary of Test Method
4.1 Volatile extractables are determined by subjecting a sample of the susceptor material to microwave heating, followed by
headspace sampling and gas chromatography. Qualitative analysis may be carried out on a gas chromatograph (GC) coupled to an
appropriate detector capable of compound identification. Volatile extractables are quantitated by comparison with standards of
known concentration.
5. Significance and Use
5.1 This test method is intended to measure volatile extractables that may be emitted from a microwave susceptor material
during use. It may be a useful procedure to assist in minimizing the amount of volatile extractables either through susceptor design
or manufacturing processes.
5.2 Modification of this procedure by utilizing appropriate qualitative GC detection such as a mass spectrometer in place of the
flame ionization detector may provide identification of volatile extractables of unknown identity.
6. Interferences
6.1 Gas Chromatography—Because of the potentially large number of chemical species that can be analyzed using this
methodology, not all species will be resolved from one another on a particular GC column under a given set of conditions.
Techniques available to the analyst to verify the identity of the species being quantitated include retention time comparisons using
alternate GC conditions or using an alternate GC column to verify identification. Good judgement of chromatographic results is
4,5,6
always important. Refer to Practice E260 for guidance.
6.2 Apparatus—Because this test method is designed for trace volatiles, and is highly sensitive, contaminants on vials, septa,
syringes, etc. can lead to misinterpretation of results. Preparing apparatus properly and carrying out blank determinations as
specified in the procedure is essential to minimize this possibility.
McCown, S. M., and Radenheimer, P., “An Equilibrium Headspace Gas Chromatographic Method for the Determination of Volatile Residues in Vegetable Oils and Fats,”
LC/GC, Vol 7, No. 11, 1989, pp. 918–924.
McNeal, T. P., and Breder, C. V., “Headspace Gas Chromatographic Determination of Residual 1,3-Butadiene in Rubber-Modified Plastics and Its Migration from Plastic
Containers Into Selected Foods,” Journal of the Association of Analytical Chemists, Vol 70, No. 1, 1987, pp. 18–21.
McNeal, T. P., and Breder, C. V., “Headspace Sampling and Gas-Solid Chromatographic Determination of Residual Acrylonitrile in Acrylonitrile Copolymer Solutions,”
Journal of the Association of Offıcial Analytical Chemists, Vol 64, No. 2, 1981, pp. 270–275.
F1308 − 98 (2018)
7. Apparatus and Reagents
7.1 Microwave Oven—Calibrated, 7006 35 W, no turntable. See Test Method F1317.
7.2 Humidity Chambers, operated at 50 % RH and 23°C.
7.2.1 Requirements for constant temperature-humidity chambers and equilibrium relative humidities over saturated salt
solutions are outlined in TAPPI Methods T 402-om-88, and TIS 808-03.
7.3 Vials, headspace, 20 mL (actual volume 21.5 mL). To ensure against extraneous peaks in the gas chromatographic traces,
wash vials thoroughly and dry in a 125°C air oven for a minimum of 4 h before using.
7.4 Vial Crimp Caps.
7.5 Septa, Polytetrafluoroethylene (PTFE)/silicone. To ensure that the septa are free of volatiles, cover the bottom of a 15-cm
petri dish with septa, PTFE-polymer side up. Microwave at full power for 10 min. Place microwaved septa into a vacuum (greater
than 29 in.) oven at 130°C for 16 h.
7.6 Crimping Tool for vials.
7.7 Syringe, 2 mL, gas-tight with valve. Store syringe in 90°C oven between uses.
7.8 Gas Chromatograph equipped as follows:
7.8.1 FID Detector, compatible with capillary columns.
7.8.2 Injector, split/splitless compatible with capillary columns.
7.8.3 Automated Headspace Sampler, Optional.
7.8.4 Column, DB-5, 30 m, 0.25-mm inside diameter, 1-μm film thickness, or 0.32 mm. (A short piece of deactivated 0.25-mm
fused silica column may be placed between the injector and the column to serve as a guard column.)
7.8.5 Peak-Area Integration System compatible with GC system. Alternatively, a chart recorder and hand integration can be
used.
7.9 Fluoroptic Thermometry System .
7.10 Temperature Probes, high temperature.
7.11 Beaker, 600 mL.
7.12 Oven, hot air, set for 90°C.
7.13 Stopwatch.
7.14 4-Heptanone.
7.15 Standard Solutions—Regular Method:
7.15.1 Internal Standard Solution (245 μg/mL 4-Heptanone)—To approximately 950 mL of distilled water in a 1-L volumetric
flask add 300 μL of 4-heptanone. Mix well and dilute to volume with water.
7.15.2 Standard Solution 1: (Prepare fresh daily.)—To approximately 475 mL of internal standard solution in a 500-mL
volumetric flask, add 50 μL of each of the compounds to be quantitated. Mix well, and dilute to volume with internal standard
solution. If difficulty is experienced with dissolution of analyte, alternate standard solution procedure may overcome this difficulty.
7.15.3 Standard Solution 2—Repeat 7.14.2 using 25 μL of each compound.
7.15.4 Standard Solution 3—Repeat 7.14.2 using 10 μL of each compound.
7.16 Standard Solutions—Alternate Method:
7.16.1 Alternate Internal Standard Solution (1225 μg/mL 4-Heptanone)—To approximately 150 mL of helium-sparged
orthodichlorobenzene (ODCB) in a 200-mL volumetric flask add 300 μL of 4-heptanone. Mix well and dilute to volume with
ODCB.
7.16.2 Alternate Standard Solution 1— To approximately 75 mL of alternate internal standard solution in a 100-mL volumetric
flask, add 50 μL of each of the compounds to be quantitated. Mix well, and dilute to volume with alternate internal standard
solution.
7.16.3 Alternate Standard Solution 2— Repeat 7.15.2 using 25 μL of each compound.
7.16.4 Alternate Standard Solution 3— Repeat 7.15.2 using 10 μL of each compound.
7.17 Susceptor Blank—Obtain a representative sample of susceptor material to be tested. Bake in an air oven overnight at 100°C
or higher to remove any volatile materials present. Store blank susceptor strips in humidity chamber 1 at 50 % RH and 23°C until
equilibrium moisture content is reached. An exposure time of 24 h is generally adequate for most paper-based products. Strips
should remain in the conditioning environment until needed for analysis.
7.18 Syringe Needle, 13 gage.
7.19 Variable Voltage Transformer, Optional—This can occasionally be used for minor adjustments to line voltage to bring
power output of the microwave oven into the specified range.
F1308 − 98 (2018)
8. Instrument Setup
8.1 Determine sample test conditions as follows:
8.1.1 Set up microwave susceptor in the configuration of its intended use, that is, a popcorn bag filled with popcorn, a pizza
disk with pizza on top, etc.
8.1.2 Place temperature probes (7.10) on susceptor surface, disturbing the normal food load as little as possible. If the susceptor
has areas where the food does not normally contact the surface, place the probes in these areas. Place the product in the center of
the microwave oven.
8.1.3 Cook the product in accordance with normal directions, for the maximum cooking time. Record this time. Record the
probe temperature(s), preferably at 5-s intervals, but at intervals not to exceed 15 s during cooking.
8.1.4 Place 250 mL of room-temperature distilled water into a 600-mL beaker. Place the beaker in the center rear of the
microwave oven.
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8.1.5 Cut a 10 by 65-mm (6.5-cm = 1-in. ) portion from the susceptor sample to be tested. Insert carefully into the 20-mL
headspace vial.
8.1.6 Using a 13-gage syringe needle, pierce a hole into a headspace vial septum. Place the septum on the vial and crimp.
8.1.7 Insert one temperature probe (7.10) through the septum hole into the vial and manipulate it until it is in contact with the
active face of the susceptor material. Place the vial on its side in the center of microwave oven, crimp end toward right of the oven,
and susceptor with active face up.
8.1.8 Microwave at full power, recording the probe temperature, preferably at 5-s intervals, but at intervals not to exceed 15 s.
8.1.9 Plot the temperatures from 8.1.3 and 8.1.8 on the same graph.
8.1.10 Compare the plots. If the trace from 8.1.8 closely approximates or is slightly higher than the plot from 8.1.3 then the test
time will be equal to the maximum product cook time of the product in that oven. If the trace is substantially higher or lower than
that of the susceptor with product, then adjust the mass or surface area, or both, (by changing container size) of the water (using
a fresh sample of room temperature distilled water) as necessary to achieve a similar profile. Record the mass of water and type
of container that gives the best agreement between the test sample and the product temperature profiles.
8.2 Set up the gas chromatographic system
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