ASTM D5524-94

Standard Test Method for Determination of Phenolic Antioxidants in High Density Polyethylene Using Liquid Chromatography

SCOPE
1.1 This test method covers a liquid-chromatographic procedure for the separation of some additives currently used in high-density polyethylene. These additives are extracted with cyclohexane prior to liquid-chromatographic separation. The ultraviolet absorbance (200 nm) of the compound(s) is measured; quantitation is performed using the internal standard method.
Note 1—There is no similar or equivalent ISO standard.
1.2 The values stated in SI units are to be regarded as the 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 9.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Replaced By: ASTM D5524-94(2001)e1 - Standard Test Method for Determination of Phenolic Antioxidants in High Density Polyethylene Using Liquid Chromatography (Withdrawn 2009)
• Effective Date: 01-Jan-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5524 – 94 An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determination of Phenolic Antioxidants in High Density
Polyethylene Using Liquid Chromatography
This standard is issued under the fixed designation D 5524; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.3.2 HDPE—high-density polyethylene.
3.4 Trade Names:
1.1 This test method covers a liquid-chromatographic pro-
3.5 BHT—2,6-di-t-butyl-cresol or butylated hydroxy tolu-
cedure for the separation of some additives currently used in
ene.
high-density polyethylene. These additives are extracted with
3.6 BHEB—2,6-di-t-butyl-4-ethyl-phenol or butylated hy-
cyclohexane prior to liquid-chromatographic separation. The
droxyethyl benzene.
ultraviolet absorbance (200 nm) of the compound(s) is mea-
3.7 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4- hy-
sured; quantitation is performed using the internal standard
droxyhydrocinnamate)]methane.
method.
3.8 Irganox 1076—octadecyl-3,5-di-t-butyl-4-hydroxy- hy-
NOTE 1—There is no similar or equivalent ISO standard. 8
drocinnamate.
1.2 The values stated in SI units are to be regarded as the 3.9 Isonox 129—2,28-ethylidene bis(4,6-di-t-butyl phenol).
standard. 3.10 Tinuvin P—2(28-hydroxy-58-methyl phenyl) benzotria-
1.3 This standard does not purport to address all of the zole.
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 4.1 The HDPE sample is ground to a 20-mesh particle size
and extracted by refluxing with cyclohexane.
bility of regulatory limitations prior to use. Specific precau-
tionary statements are given in Section 9. 4.2 The solvent extract is examined by LC.
4.3 Additive concentrations are determined relative to an
2. Referenced Documents
internal standard (contained in the solvent) using reverse-phase
2.1 ASTM Standards: chromatography (C-18 column) with ultraviolet (UV) detection
D 883 Terminology Relating to Plastics at 200 nm.
D 1600 Terminology for Abbreviated Terms Relating to
2 5. Significance and Use
Plastics
E 131 Terminology Relating to Molecular Spectroscopy 5.1 Separation and identification of stabilizers used in the
manufacture of HDPE are necessary in order to correlate
E 380 Practice for Use of the International System of Units
(SI) (the Modernized Metric System) performance properties with polymer composition. This test
method provides a means of determining BHT, BHEB, Isonox
E 691 Practice for Conducting an Interlaboratory Study to
129, Irganox 1010, and Irganox 1076 levels in HDPE samples.
Determine the Precision of a Test Method
This test method should be applicable for the determination of
3. Terminology
other antioxidants such as Cyanox 425, Cyanox 1790, Cyanox
3.1 Definitions—For definitions of plastics terms used in 2246, Ultranox 236, and Ultranox 246, but the applicability of
this test method, see Terminologies D 883 and D 1600. this test method has not been investigated for these antioxi-
3.2 Symbols:Symbols—For the units, symbols, and abbre- dants.
viations used in this test method, refer to Terminology E 131 or 5.2 The additive-extraction procedure is made effective by
Practice E 380. the insolubility of the polymer sample in solvents generally
3.3 Abbreviations: used for liquid chromatographic analysis.
3.3.1 LC—liquid chromatography. 5.3 The lowest level of detection for a phenolic antioxidant
is approximately 2 ppm under optimum conditions.
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods. Available from PMC Specialties; Uniroyal, Inc.; Borg Warner; and Rhone
Current edition approved March 15, 1994. Published May 1994. Poulank.
2 6
Annual Book of ASTM Standards, Vol 08.01. Available from R-M Industries and Gallard Schlesinger Corp.
3 7
Annual Book of ASTM Standards, Vol 14.01. Available Ciba-Geigy.
4 8
Annual Book of ASTM Standards, Vol 14.02 Available from Ciba-Geigy; Uniroyal, Inc.; Ethyl Corp.; and Borg Warner.
D 5524
5.4 Other procedures that have been used successfully to 8.2 Cyclohexane:
remove additives from the plastics matrix include thin-film, 8.2.1 Cyclohexane T-P—HPLC grade, spectro-quality or
,
9 10 10
microwave, ultrasonic, and supercritical fluid extractions. chromatography-quality reagent cyclohexane with 51.8 mg/L
11, 12
Other procedures have been used successfully to separate additives, including Tinuvin-P added as an internal standard.
12 13
SFC and capillary GC. 8.2.2 Cyclohexane—HPLC grade, spectro-quality or
chromatography-quality reagent.
6. Interferences
8.3 Water—HPLC or UV-quality reagent, degassed by
6.1 Any material eluting at or near the same retention time
sparging with high-purity helium or by filtration under
as the additive can cause erroneous results. A polymer-solvent-
vacuum.
extract solution containing no internal standard should be
8.4 Acetonitrile—HPLC, spectro-quality or chroma-
examined to minimize the possibility of interferences.
tography-quality reagent (a reagent whose UV cutoff is ap-
6.2 A major source of interferences can be from solvent
proximately 190 nm).
impurities. For this reason, the solvents should be examined
8.5 2-Propanol—HPLC grade, spectro-quality or
prior to use by injecting a sample of solvent on the HPLC
chromatography-quality reagent.
system and analyzing as in Section 10.
9. Precautions
7. Apparatus
9.1 Cyclohexane and 2-Propanol are flammable. This ex-
7.1 Liquid Chromatograph, equipped with a variable-
traction procedure should be conducted in a fume hood.
wavelength UV detector, heated column, and gradient-elution
capabilities. The liquid chromatograph should be equipped
10. Preparation of Liquid Chromatograph
with a means for a 10-μL sample solution injection such as a
10.1 Set the chromatograph to operate at the following
sample loop.
conditions:
7.2 Chromatographic Column, RP-18, 5-μm particle size,
10.1.1 Initial Mobile Phase Condition— 50 % acetonitrile
15 cm by 4.6 mm.
and 50 % water.
10.1.2 Final Mobile Phase Condition—100 % acetonitrile
NOTE 2—Vydac 201HS5415 column, Separations Group, was used in
this test method. The gradient described in 10.1 provides complete
and 0 % water.
separation of antioxidants using this RP-18 column. An equivalent column
10.1.3 Gradient Length—11 min.
may also be used.
10.1.4 Gradient Curve—Linear.
7.3 Computer System or Integrator, coupled with the chro- 10.1.5 Flow Rate—1.0 mL/min.
10.1.6 Hold at 100 % acetonitrile and 0 % water for 8 min.
matograph, recommended for measuring peak area.
7.4 Wiley Mill, equipped with a 20-mesh screen and water- 10.1.7 Return to 50 % acetonitrile and 50 % water at 19.1
min at a flow of 1.5 mL/min for 5 min.
cooled jacket to prevent the thermodegradation of antioxidants
such as BHT and BHEB. 10.1.8 Return to 1.0 mL/min flow rate at 25 min.
10.1.9 Detector—UV detector set at 200 nm and range set at
7.5 Recorder, MV-scale, dependent on the output of the
detector. 0.1 Aufs.
10.1.10 Chart Speed—12.7 mm (0.5 in.)/min.
7.6 Reflux-Extraction Apparatus, consisting of a condenser
(24/40 ground-glass joint), a flat-bottom 125-mL flask having 10.1.11 Column—Reverse phase C-18, 5 μm, 15 cm by 4.6
a 24/40 ground-glass joint, and a hot plate with magnetic stirrer mm.
(see Fig. X1.1 in Appendix X1). 10.1.12 Temperature—Column set at 60°C.
7.7 Filter System (PTFE), for nonaqueous solutions 10.1.13 Sample Size—10 μL.
(pore size of 0.22 μm), equipped with a glass S CC syringe.
11. Sample Preparation
7.8 Analytical Balance, capable of weighing to 60.0001 g.
11.1 Grind the sample to a particle size of 20-mesh using a
8. Reagents and Materials
water-cooled Wiley mill.
8.1 Tinuvin-P—2(28-hydroxy-58-methyl phenyl) benzotria-
NOTE 3—Grind 7 to8gofthe sample to run the analysis. It is important
zole.
to minimize the time of grinding to prevent any thermodegradation of the
additives in the polymer.
Freitag, W., an
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