ASTM D5524-94(2001)e1

Standard Test Method for Determination of Phenolic Antioxidants in High Density Polyethylene Using Liquid Chromatography (Withdrawn 2009)

SIGNIFICANCE AND USE
Separation and identification of stabilizers used in the manufacture of HDPE are necessary in order to correlate performance properties with polymer composition. This test method provides a means of determining BHT, BHEB, Isonox 129, Irganox 1010, and Irganox 1076 levels in HDPE samples. This test method should be applicable for the determination of other antioxidants such as Cyanox 425, Cyanox 1790, Cyanox 2246, Ultranox 236, and Ultranox 246, but the applicability of this test method has not been investigated for these antioxidants.
The additive-extraction procedure is made effective by the insolubility of the polymer sample in solvents generally used for liquid chromatographic analysis.
The lowest level of detection for a phenolic antioxidant is approximately 2 ppm under optimum conditions.
Other procedures that have been used successfully to remove additives from the plastics matrix include thin-film, microwave,10 ultrasonic,11 and supercritical fluid extractions.11 , 12 , 13 Procedures other than HPLC have been used successfully to separate additives, including SFC13 and capillary GC.14
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.
WITHDRAWN RATIONALE
This test method covered 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.
Formerly under the jurisdiction of Committee D20 on Plastics, this test method was withdrawn in February 2009 and replaced by Test Method D 6953 for Determination of Antioxidants and Erucamide Slip Additives in Polyethylene Using Liquid Chromatography (LC).

General Information

• Status: Withdrawn
• Publication Date: 31-Dec-2000
• Withdrawal Date: 31-Jan-2009
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Relations

• Replaces: ASTM D5524-94 - Standard Test Method for Determination of Phenolic Antioxidants in High Density Polyethylene Using Liquid Chromatography
• Effective Date: 01-Jan-2001

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
e1
Designation:D5524–94 (Reapproved 2001)
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.
e NOTE—Several sections were changed editorially in March 2001.
1. Scope 3.2 Symbols:Symbols—For the units, symbols, and abbre-
viationsusedinthistestmethod,refertoTerminologyE 131or
1.1 This test method covers a liquid-chromatographic pro-
IEEE/ASTM SI-10.
cedure for the separation of some additives currently used in
3.3 Abbreviations:Abbreviations:
high-density polyethylene. These additives are extracted with
3.3.1 LC—liquid chromatography.
cyclohexane prior to liquid-chromatographic separation. The
3.3.2 HDPE—high-density polyethylene.
ultraviolet absorbance (200 nm) of the compound(s) is mea-
3.4 Trade Names:
sured; quantitation is performed using the internal standard
3.5 BHT—2,6-di-t-butyl-cresol or butylated hydroxy tolu-
method.
ene.
NOTE 1—There is no similar or equivalent ISO standard.
3.6 BHEB—2,6-di-t-butyl-4-ethyl-phenol or butylated hy-
1.2 The values stated in SI units are to be regarded as the droxyethyl benzene.
standard. 3.7 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4- hy-
1.3 This standard does not purport to address all of the droxyhydrocinnamate)]methane.
safety concerns, if any, associated with its use. It is the 3.8 Irganox 1076—octadecyl-3,5-di-t-butyl-4-hydroxy- hy-
responsibility of the user of this standard to establish appro- drocinnamate.
priate safety and health practices and determine the applica- 3.9 Isonox 129—2,28-ethylidenebis(4,6-di-t-butylphenol).
bility of regulatory limitations prior to use. Specific precau- 3.10 TinuvinP—2(28-hydroxy-58-methylphenyl)benzotria-
tionary statements are given in Section 9. zole.
2. Referenced Documents 4. Summary of Test Method
2.1 ASTM Standards: 4.1 The HDPE sample is ground to a 20-mesh particle size
D 883 Terminology Relating to Plastics and extracted by refluxing with cyclohexane.
D 1600 Terminology for Abbreviated Terms Relating to 4.2 The solvent extract is analyzed by LC.
Plastics 4.3 Additive concentrations are determined relative to an
E 131 Terminology Relating to Molecular Spectroscopy internalstandard(containedinthesolvent)usingreverse-phase
E 691 Practice for Conducting an Interlaboratory Study to chromatography(C-18column)withultraviolet(UV)detection
Determine the Precision of a Test Method at 200 nm.
IEEE/ASTM SI-10 Standard for Use of the International
5 5. Significance and Use
System of Units (SI): The Modern Metric System
5.1 Separation and identification of stabilizers used in the
3. Terminology
manufacture of HDPE are necessary in order to correlate
3.1 Definitions—For definitions of plastics terms used in performance properties with polymer composition. This test
this test method, see Terminologies D 883 and D 1600. method provides a means of determining BHT, BHEB, Isonox
129, Irganox 1010, and Irganox 1076 levels in HDPE samples.
This test method should be applicable for the determination of
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved March 15, 1994. Published May 1994. Available from PMC Specialties; Uniroyal, Inc.; Borg Warner; and Rhone
Annual Book of ASTM Standards, Vol 08.01. Poulank.
Annual Book of ASTM Standards, Vol 14.01. Available from R-M Industries and Gallard Schlesinger Corp.
4 8
Annual Book of ASTM Standards, Vol 14.02 Available Ciba-Geigy.
5 9
Annual Book of ASTM Standards, Vol 14.04 Available from Ciba-Geigy; Uniroyal, Inc.; Ethyl Corp.; and Borg Warner.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D5524–94 (2001)
other antioxidants such as Cyanox 425, Cyanox 1790, Cyanox 7.6 Reflux-Extraction Apparatus, consisting of a condenser
2246, Ultranox 236, and Ultranox 246, but the applicability of (24/40 ground-glass joint), a flat-bottom 125-mL flask having
this test method has not been investigated for these antioxi- a24/40ground-glassjoint,andahotplatewithmagneticstirrer
dants. (see Fig. X1.1 in Appendix X1).
5.2 The additive-extraction procedure is made effective by 7.7 Filter System (PTFE), for nonaqueous solutions
the insolubility of the polymer sample in solvents generally (pore size of 0.22 µm), equipped with a glass 5–cc syringe.
used for liquid chromatographic analysis. 7.8 Analytical Balance, capable of weighing to 60.0001 g.
5.3 The lowest level of detection for a phenolic antioxidant
8. Reagents and Materials
is approximately 2 ppm under optimum conditions.
5.4 Other procedures that have been used successfully to 8.1 Tinuvin-P—2(28-hydroxy-58-methyl phenyl) benzotria-
remove additives from the plastics matrix include thin-film, zole.
10 11
microwave, ultrasonic, and supercritical fluid extrac- 8.2 Cyclohexane:
11, 12, 13
tions. Procedures other than HPLC have been used 8.2.1 Cyclohexane T-P—HPLC grade, spectro-quality or
successfully to separate additives, including SFC and capil- chromatography-quality reagent cyclohexane with approxi-
lary GC. mately 50 mg/L (to the nearest 0.1 mg) Tinuvin-P added as an
internal standard.
6. Interferences
8.2.2 Cyclohexane—HPLC grade, spectro-quality or
chromatography-quality reagent.
6.1 Any material eluting at or near the same retention time
8.3 Water—HPLC or UV-quality reagent, degassed by
as the additive can cause erroneous results.Apolymer-solvent-
sparging with high-purity helium or by filtration under
extract solution containing no internal standard should be
vacuum.
examined to minimize the possibility of interferences.
8.4 Acetonitrile—HPLC, spectro-quality or
6.2 A major source of interferences can be from solvent
chromatography-quality reagent (a reagent whose UV cutoff is
impurities. For this reason, the solvents should be examined
approximately 190 nm).
prior to use by injecting a sample of solvent on the HPLC
8.5 2-Propanol—HPLC grade, spectro-quality or
system and analyzing as in Section 10.
chromatography-quality reagent.
7. Apparatus
9. Precautions
7.1 Liquid Chromatograph, equipped with a variable-
9.1 Cyclohexane and 2-Propanol are flammable. This ex-
wavelength UV detector, heated column, and gradient-elution
traction procedure should be conducted in a fume hood.
capabilities. The liquid chromatograph should be equipped
with a means for a 10-µL sample solution injection such as a
10. Preparation of Liquid Chromatograph
sample loop.
10.1 Set the chromatograph to operate at the following
7.2 Chromatographic Column, RP-18, 5-µm particle size,
conditions:
15 cm by 4.6 mm.
10.1.1 Initial Mobile Phase Condition— 50 % acetonitrile
NOTE 2—Vydac 201HS5415 column, Separations Group, was used in
and 50 % water.
this test method. The gradient described in 10.1 provides complete
10.1.2 Final Mobile Phase Condition—100 % acetonitrile
separationofantioxidantsusingthisRP-18column.Anequivalentcolumn
and 0 % water.
may also be used.
10.1.3 Gradient Length—11 min.
7.3 Computer System or Integrator, coupled with the chro-
10.1.4 Gradient Curve—Linear.
matograph, for measuring peak area.
10.1.5 Flow Rate—1.0 mL/min.
7.4 Wiley Mill, equipped with a 20-mesh screen and water-
10.1.6 Hold at 100 % acetonitrile and 0 % water for 8 min.
cooled jacket to prevent the thermodegradation of antioxidants
10.1.7 Return to 50 % acetonitrile and 50 % water at 19.1
such as BHT and BHEB.
min at a flow of 1.5 mL/min for 5 min.
7.5 Recorder,millivolt-scale,dependentontheoutputofthe
10.1.8 Return to 1.0 mL/min flow rate at 25 min.
detector.
10.1.9 Detector—UVdetectorsetat200nmandrangesetat
0.1 AUFS.
10.1.10 Chart Speed—12.7 mm (0.5 in.)/min.
10 Freitag, W., and John, O., “Fast Separation of Stabilizers from Polyolefins by
10.1.11 Column—Reverse phase C-18, 5 µm, 15 cm by 4.6
Microwave Heating,” Die Angewandte Makromolekulare Chemie, Vol 175, 1990,
mm.
pp. 181–185.
Nielson, Richard, “Overview of PolyolefinAdditiveAnalysis,” Waters Report, 10.1.12 Temperature—Column set at 60°C.
Waters Chromatography Division, Milford, MA.
10.1.13 Sample Size—10 µL.
Arpino, P. J., et al., “Investigation of Antioxidants and UV Stabilizers from
Plastics, Part 1: Comparison of HPLC and SFC; Preliminary SFC/MS Study,”
11. Sample
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