ASTM D6042-09(2016)
(Test Method)Standard Test Method for Determination of Phenolic Antioxidants and Erucamide Slip Additives in Polypropylene Homopolymer Formulations Using Liquid Chromatography (LC)
Standard Test Method for Determination of Phenolic Antioxidants and Erucamide Slip Additives in Polypropylene Homopolymer Formulations Using Liquid Chromatography (LC)
SIGNIFICANCE AND USE
5.1 Separation and identification of stabilizers used in the manufacture of polypropylene is necessary in order to correlate performance properties with polymer composition. This test method provides a means to determine erucamide slip, Vitamin E, Irgafos 168, Irganox 3114, Irganox 1010, and Irganox 1076 levels in polypropylene samples. This test method is also applicable for the determination of other antioxidants, such as Ultranox 626, Ethanox 330, Santanox R, and BHT, but the applicability of this test method has not been investigated for these antioxidants.
5.2 The additive-extraction procedure is made effective by the insolubility of the polymer sample in solvents generally used for liquid chromatographic analysis.
5.3 Under optimum conditions, the lowest level of detection for a phenolic antioxidant is approximately 2 ppm.
Note 2: Other methods that have been used successfully to remove additives from the plastics matrix include thin film, microwave, ultrasonic, and supercritical fluid extractions. Other methods have been used successfully to separate additives including SFC and capillary GC.
5.4 Irgafos 168 is a phosphite antioxidant. Phosphites are known to undergo both oxidation and hydrolysis reactions. Less Irgafos 168 will be determined in the polymer when oxidation occurs during processing. The HPLC separation is capable of separating the phosphite, phosphate (oxidation product), and hydrolysis product and quantify them if standards are obtained. No significant breakdown of the phosphite antioxidant has been seen due to either extraction technique or the separation presented in this standard.
SCOPE
1.1 This test method covers a liquid-chromatographic procedure for the separation of some additives currently used in polypropylene. These additives are extracted with a cyclohexane:methylene chloride mixture using either reflux or ultrasonic bath prior to liquid-chromatographic separation. The ultraviolet absorbance (200 nm) of the compound(s) is measured, and quantitation is performed using the internal standard method.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 9.
Note 1: There is no known ISO equivalent to this test method.
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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: D6042 − 09 (Reapproved 2016)
Standard Test Method for
Determination of Phenolic Antioxidants and Erucamide Slip
Additives in Polypropylene Homopolymer Formulations
Using Liquid Chromatography (LC)
This standard is issued under the fixed designation D6042; 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 3.2 For the units, symbols, and abbreviations used in this
test method, refer to Terminology E131 or Practice IEEE/
1.1 This test method covers a liquid-chromatographic pro-
ASTM SI-10.
cedure for the separation of some additives currently used in
polypropylene. These additives are extracted with a cyclo- 3.3 Abbreviations:
hexane:methylene chloride mixture using either reflux or 3.3.1 LC—liquid chromatography.
ultrasonic bath prior to liquid-chromatographic separation.The
3.3.2 PP—polypropylene.
ultraviolet absorbance (200 nm) of the compound(s) is
3.4 Trade Names:
measured, and quantitation is performed using the internal
3.5 Vitamin E—α-Tocopherol, or 3,4-dihydro-2,5,7,8-
standard method.
tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-
1.2 This standard does not purport to address all of the
ol.
safety concerns, if any, associated with its use. It is the
3.6 Irgafos 168—Tris(2,4 di-tert-butylphenyl) phosphite.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.7 Irganox 3114—Tris(3,5-di-t-butyl-4-hydroxybenzyl)
bility of regulatory limitations prior to use. Specific precau-
isocyanurate.
tionary statements are given in Section 9.
3.8 Kemamide-E—cis-13-docosenamide or erucamide.
NOTE 1—There is no known ISO equivalent to this test method.
3.9 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4-
hydroxy hydrocinnamate)]methane.
2. Referenced Documents
3.10 Irganox 1076—octadecyl-3,5-di-t-butyl-4-hydroxy hy-
2.1 ASTM Standards:
drocinnamate.
D883 Terminology Relating to Plastics
3.11 Tinuvin P—2(2'-hydroxy-5'-methyl phenyl)benzotriaz-
D1600 Terminology forAbbreviatedTerms Relating to Plas-
ole.
tics
E131 Terminology Relating to Molecular Spectroscopy
4. Summary of Test Method
E691 Practice for Conducting an Interlaboratory Study to
4.1 The PPsample is ground to a 20-mesh particle size (850
Determine the Precision of a Test Method
microns) and extracted by refluxing with a mixture of 75:25
IEEE/ASTM SI-10 Practice for Use of the International
methylene chloride:cyclohexane or placing in an ultrasonic
System of Units (SI) (the Modernized Metric System)
bath with the same mixture.
3. Terminology
4.2 The solvent extract is examined by liquid chromatogra-
3.1 For definitions of plastic terms used in this test method,
phy.
see Terminologies D883 and D1600.
4.3 Additive concentrations are determined relative to an
internalstandard(containedinthesolvent)usingreverse-phase
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
chromatography(C-18column)withultraviolet(UV)detection
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods
at 200 nm.
(D20.70.02).
Current edition approved Sept. 1, 2016. Published September 2016. Originally
5. Significance and Use
approved in 1996. Last previous edition approved in 2009 as D6042 - 09. DOI:
10.1520/D6042-09R16.
5.1 Separation and identification of stabilizers used in the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
manufactureofpolypropyleneisnecessaryinordertocorrelate
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
performance properties with polymer composition. This test
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. method provides a means to determine erucamide slip,Vitamin
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6042 − 09 (2016)
E, Irgafos 168, Irganox 3114, Irganox 1010, and Irganox 1076
levels in polypropylene samples. This test method is also
applicable for the determination of other antioxidants, such as
Ultranox 626, Ethanox 330, Santanox R, and BHT, but the
applicability of this test method has not been investigated for
these antioxidants.
5.2 The additive-extraction procedure is made effective by
the insolubility of the polymer sample in solvents generally
used for liquid chromatographic analysis.
5.3 Under optimum conditions, the lowest level of detection
for a phenolic antioxidant is approximately 2 ppm.
NOTE 2—Other methods that have been used successfully to remove
additivesfromtheplasticsmatrixincludethinfilm,microwave,ultrasonic,
and supercritical fluid extractions. Other methods have been used success-
fully to separate additives including SFC and capillary GC.
5.4 Irgafos 168 is a phosphite antioxidant. Phosphites are
known to undergo both oxidation and hydrolysis reactions.
Less Irgafos 168 will be determined in the polymer when
oxidation occurs during processing. The HPLC separation is
capable of separating the phosphite, phosphate (oxidation
product), and hydrolysis product and quantify them if stan-
dards are obtained. No significant breakdown of the phosphite
antioxidant has been seen due to either extraction technique or
the separation presented in this standard.
6. Interferences
6.1 Any material eluting at or near the same retention time
as the additive has been known to cause erroneous results.
Examining a polymer-solvent-extract solution containing no
internal standard is recommended to minimize the possibility
of interferences.
6.2 Solvent impurity is a major source of interference. It is
a good practice to examine the solvents prior to use by
injecting a sample of solvent on the HPLC system and
analyzing as in Section 10.
FIG. 1 Sample Extraction
6.3 The oxidation product of Irgafos 168 sometimes over-
7.5 Recorder, mV scale dependent upon the output of the
laps with other additives with retention times of components
detector.
that elute between Irganox 1010 and Irgafos 168. In these
cases, run known standards to ensure that components of
7.6 Reflux Extraction Apparatus, consisting of a condenser
interest do not coelute with the oxidation product of Irgafos
(24/40 ground-glass joint), a flat bottom 125 mL flask having
168.
a24/40ground-glassjoint,andahotplatewithmagneticstirrer
(see Fig. 1).
7. Apparatus
7.7 Ultrasonic Bath Apparatus, consisting of the ultrasonic
7.1 Liquid Chromatograph, equipped with a sample
bath, a flat bottom 125-mL flask having a 24/40 ground-glass
injector, variable-wavelength ultraviolet detector, heated
joint, and a 24/40 ground-glass stopper.
column, and gradient-elution capabilities.
7.8 Filter System (Teflon) for nonaqueous solutions (pore
7.2 Chromatographic Column, RP-18, 5-µm particle size,
size of 0.45 µm or less) equipped with a glass 5-cm syringe.
15 cm by 4.6 mm.
NOTE 4—The filter shall give no ghost peak with blank solvent.
NOTE 3—AZorbax RX C-18 Column byAgilent was used for this test
7.9 Analytical Balance, capable of weighing to 60.0001 g.
method. The gradient described in 10.1 provides complete separation of
antioxidants using this C-18 column.
8. Reagents and Materials
7.3 Computer System or Integrator, coupled with the chro-
8.1 Tinuvin-P, 2(2' hydroxy-5'-methyl phenyl) benzotriaz-
matograph is recommended to measure peak area.
ole.
7.4 Wiley Mill, equipped with a 20-mesh screen and water-
cooled jacket to prevent thermodegradation of antioxidants. Registered trademark of DuPont.
D6042 − 09 (2016)
FIG. 2 HPLC Separation of Six Additives
8.2 Methylene Chloride, HPLC grade, spectral quality or 10.1.7 At 15.1 min return to 75 % acetonitrile: 25 % water
chromatography quality reagent. at a flow of 1.5 mL/min for 5 min.
10.1.8 Detector—Ultraviolet detector set at 200 nm, range
8.3 Cyclohexane, HPLC grade, spectral quality or chroma-
set at about 0.1 Aufs.
tography quality reagent.
10.1.9 Column—Reverse-phase C-18, 5 µm, 15 cm by 4.6
8.4 75:25 Methylene Chloride:Cyclohexane T-P, mixture
mm.
with 51.8 mg/L Tinuvin-P added as an internal standard.
10.1.10 Temperature—Column set at 50°C.
8.5 Water, HPLC or UV quality reagent, degassed by
10.1.11 Sample Size—10 µL or less, depends on sample
spargingwithhighpurityheliumorbyfiltrationundervacuum. concentration and instrument.
8.6 Acetonitrile, HPLC, spectral quality or chromatography
11. Sample Pre
...
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: D6042 − 09 (Reapproved 2016)
Standard Test Method for
Determination of Phenolic Antioxidants and Erucamide Slip
Additives in Polypropylene Homopolymer Formulations
Using Liquid Chromatography (LC)
This standard is issued under the fixed designation D6042; 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 3.2 For the units, symbols, and abbreviations used in this
test method, refer to Terminology E131 or Practice IEEE/
1.1 This test method covers a liquid-chromatographic pro-
ASTM SI-10.
cedure for the separation of some additives currently used in
polypropylene. These additives are extracted with a cyclo- 3.3 Abbreviations:
hexane:methylene chloride mixture using either reflux or 3.3.1 LC—liquid chromatography.
ultrasonic bath prior to liquid-chromatographic separation. The
3.3.2 PP—polypropylene.
ultraviolet absorbance (200 nm) of the compound(s) is
3.4 Trade Names:
measured, and quantitation is performed using the internal
3.5 Vitamin E—α-Tocopherol, or 3,4-dihydro-2,5,7,8-
standard method.
tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-
1.2 This standard does not purport to address all of the
ol.
safety concerns, if any, associated with its use. It is the
3.6 Irgafos 168—Tris(2,4 di-tert-butylphenyl) phosphite.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.7 Irganox 3114—Tris(3,5-di-t-butyl-4-hydroxybenzyl)
bility of regulatory limitations prior to use. Specific precau-
isocyanurate.
tionary statements are given in Section 9.
3.8 Kemamide-E—cis-13-docosenamide or erucamide.
NOTE 1—There is no known ISO equivalent to this test method.
3.9 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4-
hydroxy hydrocinnamate)]methane.
2. Referenced Documents
3.10 Irganox 1076—octadecyl-3,5-di-t-butyl-4-hydroxy hy-
2.1 ASTM Standards:
drocinnamate.
D883 Terminology Relating to Plastics
3.11 Tinuvin P—2(2'-hydroxy-5'-methyl phenyl)benzotriaz-
D1600 Terminology for Abbreviated Terms Relating to Plas-
ole.
tics
E131 Terminology Relating to Molecular Spectroscopy
4. Summary of Test Method
E691 Practice for Conducting an Interlaboratory Study to
4.1 The PP sample is ground to a 20-mesh particle size (850
Determine the Precision of a Test Method
microns) and extracted by refluxing with a mixture of 75:25
IEEE/ASTM SI-10 Practice for Use of the International
methylene chloride:cyclohexane or placing in an ultrasonic
System of Units (SI) (the Modernized Metric System)
bath with the same mixture.
3. Terminology
4.2 The solvent extract is examined by liquid chromatogra-
3.1 For definitions of plastic terms used in this test method,
phy.
see Terminologies D883 and D1600.
4.3 Additive concentrations are determined relative to an
internal standard (contained in the solvent) using reverse-phase
This test method is under the jurisdiction of ASTM Committee D20 on Plastics chromatography (C-18 column) with ultraviolet (UV) detection
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods
at 200 nm.
(D20.70.02).
Current edition approved Sept. 1, 2016. Published September 2016. Originally
5. Significance and Use
approved in 1996. Last previous edition approved in 2009 as D6042 - 09. DOI:
10.1520/D6042-09R16.
5.1 Separation and identification of stabilizers used in the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
manufacture of polypropylene is necessary in order to correlate
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
performance properties with polymer composition. This test
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. method provides a means to determine erucamide slip, Vitamin
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6042 − 09 (2016)
E, Irgafos 168, Irganox 3114, Irganox 1010, and Irganox 1076
levels in polypropylene samples. This test method is also
applicable for the determination of other antioxidants, such as
Ultranox 626, Ethanox 330, Santanox R, and BHT, but the
applicability of this test method has not been investigated for
these antioxidants.
5.2 The additive-extraction procedure is made effective by
the insolubility of the polymer sample in solvents generally
used for liquid chromatographic analysis.
5.3 Under optimum conditions, the lowest level of detection
for a phenolic antioxidant is approximately 2 ppm.
NOTE 2—Other methods that have been used successfully to remove
additives from the plastics matrix include thin film, microwave, ultrasonic,
and supercritical fluid extractions. Other methods have been used success-
fully to separate additives including SFC and capillary GC.
5.4 Irgafos 168 is a phosphite antioxidant. Phosphites are
known to undergo both oxidation and hydrolysis reactions.
Less Irgafos 168 will be determined in the polymer when
oxidation occurs during processing. The HPLC separation is
capable of separating the phosphite, phosphate (oxidation
product), and hydrolysis product and quantify them if stan-
dards are obtained. No significant breakdown of the phosphite
antioxidant has been seen due to either extraction technique or
the separation presented in this standard.
6. Interferences
6.1 Any material eluting at or near the same retention time
as the additive has been known to cause erroneous results.
Examining a polymer-solvent-extract solution containing no
internal standard is recommended to minimize the possibility
of interferences.
6.2 Solvent impurity is a major source of interference. It is
a good practice to examine the solvents prior to use by
injecting a sample of solvent on the HPLC system and
analyzing as in Section 10.
FIG. 1 Sample Extraction
6.3 The oxidation product of Irgafos 168 sometimes over-
7.5 Recorder, mV scale dependent upon the output of the
laps with other additives with retention times of components
detector.
that elute between Irganox 1010 and Irgafos 168. In these
cases, run known standards to ensure that components of
7.6 Reflux Extraction Apparatus, consisting of a condenser
interest do not coelute with the oxidation product of Irgafos
(24/40 ground-glass joint), a flat bottom 125 mL flask having
168.
a 24/40 ground-glass joint, and a hot plate with magnetic stirrer
(see Fig. 1).
7. Apparatus
7.7 Ultrasonic Bath Apparatus, consisting of the ultrasonic
7.1 Liquid Chromatograph, equipped with a sample
bath, a flat bottom 125-mL flask having a 24/40 ground-glass
injector, variable-wavelength ultraviolet detector, heated
joint, and a 24/40 ground-glass stopper.
column, and gradient-elution capabilities.
7.8 Filter System (Teflon) for nonaqueous solutions (pore
7.2 Chromatographic Column, RP-18, 5-µm particle size,
size of 0.45 µm or less) equipped with a glass 5-cm syringe.
15 cm by 4.6 mm.
NOTE 4—The filter shall give no ghost peak with blank solvent.
NOTE 3—A Zorbax RX C-18 Column by Agilent was used for this test
7.9 Analytical Balance, capable of weighing to 60.0001 g.
method. The gradient described in 10.1 provides complete separation of
antioxidants using this C-18 column.
8. Reagents and Materials
7.3 Computer System or Integrator, coupled with the chro-
8.1 Tinuvin-P, 2(2' hydroxy-5'-methyl phenyl) benzotriaz-
matograph is recommended to measure peak area.
ole.
7.4 Wiley Mill, equipped with a 20-mesh screen and water-
cooled jacket to prevent thermodegradation of antioxidants. Registered trademark of DuPont.
D6042 − 09 (2016)
FIG. 2 HPLC Separation of Six Additives
8.2 Methylene Chloride, HPLC grade, spectral quality or 10.1.7 At 15.1 min return to 75 % acetonitrile: 25 % water
chromatography quality reagent. at a flow of 1.5 mL/min for 5 min.
10.1.8 Detector—Ultraviolet detector set at 200 nm, range
8.3 Cyclohexane, HPLC grade, spectral quality or chroma-
set at about 0.1 Aufs.
tography quality reagent.
10.1.9 Column—Reverse-phase C-18, 5 µm, 15 cm by 4.6
8.4 75:25 Methylene Chloride:Cyclohexane T-P, mixture
mm.
with 51.8 mg/L Tinuvin-P added as an internal standard.
10.1.10 Temperature—Column set at 50°C.
8.5 Water, HPLC or UV quality reagent, degassed by 10.1.11 Sample Size—10 µL or less, depends on sample
sparging with high purity helium or by filtration under vacuum.
concentration and instrument.
8.6 Acetonitrile, HPLC, spectral quality or chromatography
11. Sample Preparation
quality reagent (a reagent whose UV cut-off is about 190 nm).
11.1 Grind the sample to
...
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: D6042 − 09 D6042 − 09 (Reapproved 2016)
Standard Test Method for
Determination of Phenolic Antioxidants and Erucamide Slip
Additives in Polypropylene Homopolymer Formulations
Using Liquid Chromatography (LC)
This standard is issued under the fixed designation D6042; 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*Scope
1.1 This test method covers a liquid-chromatographic procedure for the separation of some additives currently used in
polypropylene. These additives are extracted with a cyclohexane:methylene chloride mixture using either reflux or ultrasonic bath
prior to liquid-chromatographic separation. The ultraviolet absorbance (200 nm) of the compound(s) is measured, and quantitation
is performed using the internal standard method.
1.2 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 and health practices and determine the applicability of regulatory
limitations prior to use. Specific precautionary statements are given in Section 9.
NOTE 1—There is no known ISO equivalent to this test method.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
E131 Terminology Relating to Molecular Spectroscopy
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
IEEE/ASTM SI-10 Practice for Use of the International System of Units (SI) (the Modernized Metric System)
3. Terminology
3.1 For definitions of plastic terms used in this test method, see Terminologies D883 and D1600.
3.2 For the units, symbols, and abbreviations used in this test method, refer to Terminology E131 or Practice IEEE/ASTM
SI-10.
3.3 Abbreviations:
3.3.1 LC—liquid chromatography.
3.3.2 PP—polypropylene.
3.4 Trade Names:
3.5 Vitamin E—α-Tocopherol, or 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6- ol.
3.6 Irgafos 168—Tris(2,4 di-tert-butylphenyl) phosphite.
3.7 Irganox 3114—Tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.
3.8 Kemamide-E—cis-13-docosenamide or erucamide.
3.9 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4-hydroxy hydrocinnamate)]methane.
3.10 Irganox 1076—octadecyl-3,5-di-t-butyl-4-hydroxy hydrocinnamate.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods
(D20.70.02).
Current edition approved Sept. 1, 2009Sept. 1, 2016. Published September 2009September 2016. Originally approved in 1996. Last previous edition approved in 20042009
as D6042 - 04.D6042 - 09. DOI: 10.1520/D6042-09.10.1520/D6042-09R16.
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 ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6042 − 09 (2016)
3.11 Tinuvin P—2(2'-hydroxy-5'-methyl phenyl)benzotriazole.
4. Summary of Test Method
4.1 The PP sample is ground to a 20-mesh particle size (850 microns) and extracted by refluxing with a mixture of 75:25
methylene chloride:cyclohexane or placing in an ultrasonic bath with the same mixture.
4.2 The solvent extract is examined by liquid chromatography.
4.3 Additive concentrations are determined relative to an internal standard (contained in the solvent) using reverse-phase
chromatography (C-18 column) with ultraviolet (UV) detection at 200 nm.
5. Significance and Use
5.1 Separation and identification of stabilizers used in the manufacture of polypropylene is necessary in order to correlate
performance properties with polymer composition. This test method provides a means to determine erucamide slip, Vitamin E,
Irgafos 168, Irganox 3114, Irganox 1010, and Irganox 1076 levels in polypropylene samples. This test method is also applicable
for the determination of other antioxidants, such as Ultranox 626, Ethanox 330, Santanox R, and BHT, but the applicability of this
test method has not been investigated for these antioxidants.
5.2 The additive-extraction procedure is made effective by the insolubility of the polymer sample in solvents generally used for
liquid chromatographic analysis.
5.3 Under optimum conditions, the lowest level of detection for a phenolic antioxidant is approximately 2 ppm.
NOTE 2—Other methods that have been used successfully to remove additives from the plastics matrix include thin film, microwave, ultrasonic, and
supercritical fluid extractions. Other methods have been used successfully to separate additives including SFC and capillary GC.
5.4 Irgafos 168 is a phosphite antioxidant. Phosphites are known to undergo both oxidation and hydrolysis reactions. Less
Irgafos 168 will be determined in the polymer when oxidation occurs during processing. The HPLC separation is capable of
separating the phosphite, phosphate (oxidation product), and hydrolysis product and quantify them if standards are obtained. No
significant breakdown of the phosphite antioxidant has been seen due to either extraction technique or the separation presented in
this standard.
6. Interferences
6.1 Any material eluting at or near the same retention time as the additive has been known to cause erroneous results. Examining
a polymer-solvent-extract solution containing no internal standard is recommended to minimize the possibility of interferences.
6.2 Solvent impurity is a major source of interference. It is a good practice to examine the solvents prior to use by injecting
a sample of solvent on the HPLC system and analyzing as in Section 10.
6.3 The oxidation product of Irgafos 168 sometimes overlaps with other additives with retention times of components that elute
between Irganox 1010 and Irgafos 168. In these cases, run known standards to ensure that components of interest do not coelute
with the oxidation product of Irgafos 168.
7. Apparatus
7.1 Liquid Chromatograph, equipped with a sample injector, variable-wavelength ultraviolet detector, heated column, and
gradient-elution capabilities.
7.2 Chromatographic Column, RP-18, 5-μm particle size, 15 cm by 4.6 mm.
NOTE 3—A Zorbax RX C-18 Column by Agilent was used for this test method. The gradient described in 10.1 provides complete separation of
antioxidants using this C-18 column.
7.3 Computer System or Integrator, coupled with the chromatograph is recommended to measure peak area.
7.4 Wiley Mill, equipped with a 20-mesh screen and water-cooled jacket to prevent thermodegradation of antioxidants.
7.5 Recorder, mV scale dependent upon the output of the detector.
7.6 Reflux Extraction Apparatus, consisting of a condenser (24/40 ground-glass joint), a flat bottom 125 mL flask having a 24/40
ground-glass joint, and a hot plate with magnetic stirrer (see Fig. 1).
7.7 Ultrasonic Bath Apparatus, consisting of the ultrasonic bath, a flat bottom 125-mL flask having a 24/40 ground-glass joint,
and a 24/40 ground-glass stopper.
3 3
7.8 Filter System (Teflon) for nonaqueous solutions (pore size of 0.45 μm or less) equipped with a glass 5-cm syringe.
NOTE 4—The filter shall give no ghost peak with blank solvent.
Registered trademark of DuPont.
D6042 − 09 (2016)
FIG. 1 Sample Extraction
7.9 Analytical Balance, capable of weighing to 60.0001 g.
8. Reagents and Materials
8.1 Tinuvin-P, 2(2' hydroxy-5'-methyl phenyl) benzotriazole.
8.2 Methylene Chloride, HPLC grade, spectral quality or chromatography quality reagent.
8.3 Cyclohexane, HPLC grade, spectral quality or chromatography quality reagent.
8.4 75:25 Methylene Chloride:Cyclohexane T-P, mixture with 51.8 mg/L Tinuvin-P added as an internal standard.
8.5 Water, HPLC or UV quality reagent, degassed by sparging with high purity helium or by filtration under vacuum.
8.6 Acetonitrile, HPLC, spectral quality or chromatography quality reagent (a reagent whose UV cut-off is about 190 nm).
8.7 Isopropanol, HPLC, spectral quality or chromatography quality reagent.
9. Safety and Precautions
9.1 Methylene chloride and cyclohexane are flammable and toxic. Perform this extraction procedure in a fume hood.
10. Preparation of Liquid Chromatograph
10.1 Set the chromatograph to operate at the following conditions (see Fig. 2 for an example chromatogram):
10.1.1 Initial Mobile Phase Condition—75 % acetonitrile: 25 % water or whatever is appropriate for column used in or
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