ASTM F2013-10(2023)
(Test Method)Standard Test Method for Determination of Residual Acetaldehyde in Polyethylene Terephthalate Bottle Polymer Using an Automated Static Head-Space Sampling Device and a Capillary GC with a Flame Ionization Detector
Standard Test Method for Determination of Residual Acetaldehyde in Polyethylene Terephthalate Bottle Polymer Using an Automated Static Head-Space Sampling Device and a Capillary GC with a Flame Ionization Detector
SIGNIFICANCE AND USE
5.1 This test method is of particular use as a quality control tool for a molding or synthesis operation. Acetaldehyde is a volatile degradation product generated during melt processing of PET. Thus, it becomes trapped in the sidewalls of a molded article and desorbs slowly into the contents packaged therein. In some foods and beverages AA can impart an off-taste that is undesirable, thus, it is important to know its concentration in PET articles that are to be used in food contact applications.
5.2 The desorption conditions of 150 °C for 60 min are such that no measurable AA is generated by the sample during the desorption process.
SCOPE
1.1 This test method covers a gas chromatographic procedure for the determination of the ppm residual acetaldehyde (AA) present in poly(ethylene terephthalate) (PET) homo-polymers and co-polymers which are used in the manufacture of beverage bottles. This includes sample types of both amorphous and solid-stated pellet and preform samples, as opposed to the bottle test, Test Method D4509, an acetaldehyde test requiring 24 h of desorption time at 23 °C into the bottle headspace and then the concentration of the headspace quantified by a similar GC method.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
1.4 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.
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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.
Designation: F2013 − 10 (Reapproved 2023)
Standard Test Method for
Determination of Residual Acetaldehyde in Polyethylene
Terephthalate Bottle Polymer Using an Automated Static
Head-Space Sampling Device and a Capillary GC with a
Flame Ionization Detector
This standard is issued under the fixed designation F2013; 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 (AIR) Space Acetaldehyde Content of Freshly Blown PET
Bottles (Withdrawn 2004)
1.1 This test method covers a gas chromatographic proce-
E691 Practice for Conducting an Interlaboratory Study to
dure for the determination of the ppm residual acetaldehyde
Determine the Precision of a Test Method
(AA) present in poly(ethylene terephthalate) (PET) homo-
polymers and co-polymers which are used in the manufacture
3. Terminology
of beverage bottles. This includes sample types of both
3.1 The terms employed in this test method are commonly
amorphous and solid-stated pellet and preform samples, as
used in normal laboratory practice and require no special
opposed to the bottle test, Test Method D4509, an acetaldehyde
comment.
test requiring 24 h of desorption time at 23 °C into the bottle
headspace and then the concentration of the headspace quan-
4. Summary of Test Method
tified by a similar GC method.
4.1 A specified size (< 1000 μm) of granulated sample is
1.2 The values stated in SI units are to be regarded as
weighed into a 20 mL head-space vial, sealed, and then heated
standard. No other units of measurement are included in this
at 150 °C for 60 min. After heating, the gas above the sealed
standard.
sample of PET polymer is injected onto a capillary GC column.
1.3 This standard does not purport to address all of the
The acetaldehyde is separated, and the ppm of acetaldehyde is
safety concerns, if any, associated with its use. It is the
calculated.
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 This test method is of particular use as a quality control
1.4 This international standard was developed in accor-
tool for a molding or synthesis operation. Acetaldehyde is a
dance with internationally recognized principles on standard-
volatile degradation product generated during melt processing
ization established in the Decision on Principles for the
of PET. Thus, it becomes trapped in the sidewalls of a molded
Development of International Standards, Guides and Recom-
article and desorbs slowly into the contents packaged therein.
mendations issued by the World Trade Organization Technical
In some foods and beverages AA can impart an off-taste that is
Barriers to Trade (TBT) Committee.
undesirable, thus, it is important to know its concentration in
PET articles that are to be used in food contact applications.
2. Referenced Documents
5.2 The desorption conditions of 150 °C for 60 min are such
2.1 ASTM Standards:
that no measurable AA is generated by the sample during the
D4509 Test Methods for Determining the 24-Hour Gas
desorption process.
6. Sources of Error
This test method is under the jurisdiction of ASTM Committee F02 on Primary
6.1 A bias is known to exist if the ratio of sample mass (mg)
Barrier Packaging and is the direct responsibility of Subcommittee F02.15 on
to head-space vial volume (mL) exceeds a value of ten.
Chemical/Safety Properties.
Current edition approved April 1, 2023. Published April 2023. Originally
6.2 Acetaldehyde is very volatile and must be handled
approved in 2000. Last previous edition published in 2016 as F2013 – 10(2016).
carefully to avoid sample loss during the calibration procedure.
DOI: 10.1520/F2013-10R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2013 − 10 (2023)
Storing the standard vials in a refrigerator (4 °C 6 2 °C) is a 8.2 Liquid Nitrogen, plant grade (R-3, S-3).
must to minimize the error due to volatility.
9. Calibration and Standardization
6.3 Failure to achieve a tight seal on the head-space vial will
NOTE 1—The following procedure should be performed and recorded
result in the loss of acetaldehyde during storage and
once every three months.
desorption, producing a false low value.
9.1 Break open a certified AA standard ampule (ampules
6.4 Failure to grind the sample to the appropriate particle
must be stored in a refrigerator) or prepare AA standard by the
size may lead to a false low value for residual AA due to the
attached supplemental procedure. (See Appendix X5.)
increased path length for desorption.
9.2 Using the syringe, fill it by placing the tip in the liquid
6.5 Samples submitted for “residual AA measurement”
standard and quickly moving the plunger up and down several
should be stored in a freezer (< –10 °C) until they are tested.
time to evacuate any bubbles, then pull the plunger back past
Failure to do so can result in lower than expected results.
the 2.000 μL mark to 2.200 μL to 2.250 μL.
6.6 Excessive grinding of samples can cause residual AA
9.3 Wipe the syringe needle with a tissue.
contained therein to be desorbed. Extensive excessive grinding
9.4 Depress the plunger until the digital readout is 2.000 μL.
can lead to actual melting of the polymer and AA generation.
9.5 Smear the excess liquid that is on the syringe tip on the
Samples which have been chilled in liquid nitrogen properly
OUTSIDE of the headspace vial.
should only be in the grinder for ;30 s or less.
9.6 Place the syringe inside of the vial so that the tip just
7. Apparatus
touches the bottom of the vial.
7.1 Gas Chromatograph, equipped with a flame ionization
9.7 Quickly inject the liquid standard into the vial and swirl
detector.
the syringe tip around the inside of the vial to smear all liquid
on the vial walls.
7.2 Integrator or a PC with data acquisition software.
9.8 Remove the syringe and IMMEDIATELY cap the vial.
7.3 Head-Space Sampler—(a static head-space sampler).
9.9 Calculate the weight of AA based on the standard’s
7.4 Column, 30 m by 0.53 mm inside diameter (DVB po-
certified value and a 2.000 μL injection volume.
rous megabore capillary column or equivalent).
NOTE 2—Acetaldehyde is very volatile. The AA ampules must be stored
7.5 Vials, 20 mL, head-space, with 20 mm septa, 20 mm
in a refrigerator, and the standards prepared immediately after breaking
aluminum caps, and crimper for 20 mm caps.
open an ampule.
7.6 Crimper, 20 mm.
9.10 Analyze the working standard by the procedure de-
7.7 Decrimper, 20 mm.
scribed in Section 11, starting with 11.2.11.
7.8 Wiley Mill, equipped with an 800 μm to 1000 μm screen,
9.11 Calculate an AA response factor for the standard using
or equivalent.
the following equation:
7.9 Syringe, (gas tight) calibrated, with certificate of cali-
response factor of AA 5 Wt of AA in µg/area of AA (1)
bration. NOTE 3—Due to the error associated with the certified standard, 9.1 –
9.11 should be performed five times using five different standard ampules.
7.10 Small Vacuum Cleaner, with hose attachment for clean-
9.12 Average the five response factors obtained, and use this
ing.
value for the sample analyses.
7.11 Analytical Balance, capable of accurately weighing to
9.13 Manually enter the calculated response factor in the
at least 60.0001 g.
calibration list of the integrator or data system.
7.12 Hammer.
NOTE 4—During a series of sample analyses, a periodic check of
7.13 Air for EID.
instrument performance is recommended by placing a few liquid standard
samples throughout the sample set. If these values fall out of the
7.14 Helium 99.9995 % purity as carrier gas.
acceptable range as specified by the certificate of analysis, recalibration
7.15 Hydrogen 99.9995 % purity for flame ionization detec-
(9.1 – 9.12) should be performed.
tor (FID) or can be used as carrier gas.
10. Sample Preparation
7.16 Spatular.
10.1 Parisons or Preforms or Plaques—May be cryogeni-
7.17 Dewer flask.
cally ground whole, or can be broken into small pieces with a
7.18 Glass jar or manila envelope.
hammer (using liquid nitrogen) and then ground with the aid of
grinding mill equipped with a 20-mesh or <1000-μm screen.
7.19 Wipe paper or tissue.
The grind should be thoroughly homogenized before sampling
7.20 Digital syringe, equipped with a 10 L glass syringe.
for AA. If the appropriate size screen is not available on the
large grinding mill, then it is suggested that the sample be
8. Reagents and Materials
ground to 3 mm to 6 mm on the large mill and the sample
8.1 Acetaldehyde (AA), 500 ppm AA in water (or 1000 thoroughly homogenized. A portion can then be taken to a
ppm), purchased certified standard. smaller mill equipped with the 20 mesh or <1000 μm screen
F2013 − 10 (2023)
and cryogenically ground again before analysis. Again the final 11.2.16 To determine the mass of AA from the sample, area
sample should be thoroughly homogenized. of AA multiplied by response factor.
11.2.17 To determine the concentration in ppm of AA in the
10.2 Pellets—May be cryogenically ground in a small
polymer sample, divide the mass of AA (reported in 11.2.16)
grinding mill using liquid nitrogen. The final sample should be
by the sample weight in the vial (recorded in 11.2.9 as grams
thoroughly homogenized before sampling for analysis.
of polymer).
NOTE 5—Samples, either preforms, plaques, or pellets, should be
chilled in the liquid nitrogen for several minutes until the liquid nitrogen
12. Calculation
stops boiling and then dropped immediately into the grinder. Sample
12.1 The AA response factor is calculated as described in
should be sufficiently ground in a few seconds. The grinder should not be
allowed to operate more than 20 s to 30 s as in such cases undesirable 9.11 and 9.12. The ppm of AA can be calculated manually by
sample heating can occur.
multiplying the response factor and the area of the AA peak,
and then dividing this number by the sample weight in the vial
11. Procedure
(in grams).
NOTE 6—Refer to the general operating manual for gas chromatograph,
the head-space sampler, and the series integrator for instructions in
13. Report
performing steps in this procedure.
13.1 Report the ppm or μg/g of AA to two decimal places.
11.1 Adjust the gas chromatograph to the conditions speci-
fied in Appendix X1. Adjust the head-space sampler to the
14. Precision and Bias
conditions in Appendix X2. Set the series integrator to the
14.1 The following was taken from work completed by the
conditions in Appendix X3.
International Society of Beverage Technologists (ISBT) sub-
11.2 Sample Analysis:
committee concerning standardization of method to determine
11.2.1 Place 2 to 3 of polymer pellets (or crushed preform)
residual AA in PET.
into a small Dewar flask.
11.2.2 Cover the polymer with 20 mL to 40 mL of liquid 14.2 The number of laboratories, materials, and determina-
tions in this study meets the minimum requirements for
nitrogen.
11.2.3 Allow the polymer to chill under the liquid nitrogen determining precision in accordance with Practice E691. A
complete report is on file at ASTM Headquarters.
for approximately 3 min (or until most of the liquid N2 has
evaporated).
14.3 This round robin was conducted by having one labo-
11.2.4 Turn on the Wiley mill equipped with a 800 μm to
ratory mold PET preforms on a 48 cavity injection molding
1000 μm screen.
machine and selecting 6 of those cavities as the sample set.
11.2.5 Slowly pour the remaining liquid nitrogen from the
Even though these preforms all came from one PET sample
Dewar flask through the Wiley mill, followed by the chilled
(material), each cavity has its own unique AA value, and thus,
polymer sample (tapping the sample may be required).
were treated as six different materials. Also, two different types
11.2.6 Collect the ground polymer in a small glass jar or
of precision and bias were calculated, one based on each
small manila envelope.
laboratory using their own calibration standard solution and
11.2.7 Turn off the Wiley mill and clean it with a vacuum
another when each laboratory calibrated with a “common”
cleaner.
calibration standard.
11.2.8 Allow the ground polymer sample to come to room
Practice E691 Study Minimum
temperature (approximately 10 min).
Laboratories: 6 6
11.2.9 Weigh approximately 0.2000 g (6 0.0200 g), re- Materials: 6 4
Determinations: 3 2
corded to the nearest 0.0001 g, into a 20 mL head-space vial.
14.4 Precision and Bias With Each Laboratory Using Their
11.2.10 Place a septum (with TFE-fluorocarbon side down
Own Calibration Standard—Precision, characterized by
towards the inside of the vial) on the vial. Place an aluminum
repeatability, Sr and r, and reproducibility, SR and R, has been
cap on top of the septum, and crimp the cap with a crimper
determined for the materials to be as follows:
UNTIL THE CAP CANNOT BE TURNED. Remove the
center piece of the aluminum cap (if it exists).
Materials Average Sr SR r R
Material A 5.21 0.1812 0.6403 0.5074 1.7928
11.2.11 Place the vial in the appropriate position in the
Material B 6.25 0.4060 0.7464 1.1368 2.0899
head-space sampler.
Material C 6.37 0.2880 0.6713 0.8066 1.8796
11.2.12 Set up head space sampler and a GC acquisition
Material D 7.21 0.3285 0.7743 0.9198 2.1680
Material E 7.01 0.4217 0.8350 1.1808 2.3380
program condition as listed in Table X1.1 and Table X2.1,
Material F 5.88 0.3930 0.7168 1.1003 2.0071
following instrument operating instructions from manufacturer.
14.4.1 Since the materials used in this study are all from one
11.2.13 The head-space sampler will heat the sample for 60
specific type of material (PET), but have different AA levels
min at 150 °C and then automatically inject the head-space gas
because they are from different cavities, it makes more sense to
and start the gas chromatograph and integrator or data acqui-
have one set of precision values rather than one for each cavity.
sition software.
11.2.14 The final report will appear on the integrator or the
data s
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