ASTM D1996-97(2003)
(Test Method)Standard Test Method for Determination of Phenolic Antioxidants and Erucamide Slip Additives in Low Density Polyethylene Using Liquid Chromatography (LC) (Withdrawn 2009)
Standard Test Method for Determination of Phenolic Antioxidants and Erucamide Slip Additives in Low Density Polyethylene Using Liquid Chromatography (LC) (Withdrawn 2009)
SIGNIFICANCE AND USE
Separation and identification of stabilizers used in the manufacture of low density polyethylene are necessary in order to correlate performance properties with polymer composition. This test method provides a means to determine the BHT, BHEB, Isonox-129, erucamide slip, Irganox-1010 and Irganox-1076 levels in low density polyethylene samples.
The additive extraction procedure is made effective by the insolubility of the polymer sample in solvents generally used for liquid chromatographic analysis.
Under optimum conditions, the lowest level of detection for a phenolic antioxidant is approximately 2 ppm.
SCOPE
1.1 This test method describes a liquid chromatograph procedure for the separation of some additives currently used in low density polyethylene. These additives are extracted with 2-propanol prior to liquid chromatographic separation. The ultraviolet absorbance (200 nm) of the compound(s) is measured; 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. For a specific hazards statement, see Section 9.
Note 1—There is no similar or equivalent ISO standard.
WITHDRAWN RATIONALE
This test method described a liquid chromatograph procedure for the separation of some additives currently used in low density polyethylene. These additives are extracted with 2-propanol 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Formerly under the jurisdiction of Committee D20 on Plastics, this test method was withdrawn in February 2009 and replaced by Test Method D 6953 for Determination of Antioxidants and Erucamide Slip Additives in Polyethylene Using Liquid Chromatography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
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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:D1996–97 (Reapproved 2003)
Standard Test Method for
Determination of Phenolic Antioxidants and Erucamide Slip
Additives in Low Density Polyethylene Using Liquid
Chromatography (LC)
This standard is issued under the fixed designation D 1996; 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* 3.1.3 Irganox 1010—tetrakis[methylene(3,5-di-t-butyl-4-
hydroxyhydrocinnamate)].
1.1 This test method describes a liquid chromatograph
3.1.4 Irganox 1076—octadecyl 3-(38,58-t-butyl-4-
procedure for the separation of some additives currently used
hydroxyphenyl) propionate.
in low density polyethylene.These additives are extracted with
3.1.5 Isonox 129—2,28-ethylidene bis(4,6-di-t-butyl hy-
2-propanol prior to liquid chromatographic separation. The
droxybenzene).
ultraviolet absorbance (200 nm) of the compound(s) is mea-
3.1.6 Kemamide-E—cis-13-docosenamide, erucamide.
sured; quantitation is performed using the internal standard
3.1.7 LC—liquid chromatography.
method.
3.1.8 LDPE—low density polyethylene.
1.2 This standard does not purport to address all of the
3.1.9 Tinuvin P—2(28-hydroxy-58-methyl phenyl) benzot-
safety concerns, if any, associated with its use. It is the
riazole, Ciba-Geigy Industrial Chemicals.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Summary of Test Method
bility of regulatory limitations prior to use. For a specific
4.1 The LDPE sample is ground to a 20-mesh particle size
hazards statement, see Section 9.
and extracted by refluxing with 2-propanol.
NOTE 1—There is no similar or equivalent ISO standard.
4.2 The solvent extract is examined by liquid chromatogra-
phy.
2. Referenced Documents
4.3 Additive concentrations are determined relative to an
2.1 ASTM Standards:
internal standard (contained in the solvent) using reverse phase
E 131 Terminology Relating to Molecular Spectroscopy
chromatography(C-18column)withultraviolet(UV)detection
E 177 Practice for Use of the Terms Precision and Bias in
at 200 nm.
ASTM Test Methods
E 682 Practice for Liquid Chromatography Terms and Re- 5. Significance and Use
lationships
5.1 Separation and identification of stabilizers used in the
E 691 Practice for Conducting an Interlaboratory Study to
manufactureoflowdensitypolyethylenearenecessaryinorder
Determine the Precision of a Test Method
to correlate performance properties with polymer composition.
IEEE/ASTM SI 10 Standard for Use of the International
This test method provides a means to determine the BHT,
System of Units (SI)
BHEB,Isonox-129,erucamideslip,Irganox-1010andIrganox-
1076 levels in low density polyethylene samples.
3. Terminology
5.2 The additive extraction procedure is made effective by
3.1 Abbreviations:
the insolubility of the polymer sample in solvents generally
3.1.1 BHEB—2,6-di-t-butyl-4-ethyl-hydroxybenzene or bu-
used for liquid chromatographic analysis.
tylated hydroxyethylbenzene.
5.3 Under optimum conditions, the lowest level of detection
3.1.2 BHT—2,6-di-t-butyl-4-methyl hydroxybenzene or bu-
for a phenolic antioxidant is approximately 2 ppm.
tylated hydroxytoluene.
6. Interferences
6.1 Any material eluting at or near the same retention times
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi- as the additive or as the internal standard can cause erroneous
als.
results. A polymer solvent extract solution containing no
Current edition approved March 10, 2003. Published April 2003. Originally
approved in 1992. Last previous edition approved in 1997 as D 1996 – 97.
Annual Book of ASTM Standards, Vol 03.06.
Annual Book of ASTM Standards, Vol 14.02.
*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.
D1996–97 (2003)
internal standard should be examined to minimize the possi- 10.1.7 At 19.1 min return to 50 % acetonitrile: 50 % water
bility of interferences. at a flow of 1.5 mL/min for 5 min.
6.2 A major source of interferences can be from solvent 10.1.8 At 25 min return to 1.0 mL/min flow rate.
impurities; therefore, the solvents should be examined prior to 10.1.9 Detector—Ultraviolet detector set at 200 nm, range
use. set at about 0.1 Aufs.
10.1.10 Chart Speed—0.5 in./min.
7. Apparatus 10.1.11 Column—Reverse phase C-18, 5 micron, 15 by 4.6
mm.
7.1 Liquid Chromatograph, equipped with a variable wave-
10.1.12 Temperature—Column set at 60°C.
length ultraviolet detector, heated column, and gradient elution
10.1.13 Sample Size—10 µL.
capabilities. The liquid chromatograph should be equipped
with a means for a 10-microliter sample solution injection such
11. Calibration by Internal Standard
as a sample loop.
7.2 Chromatographic Column, RP-18, 5 micron spherical
11.1 Weigh accurately into a 125-mLflat bottom flask 50 6
particle, 15 by 4.6 mm; Vydac 201TP5415, Separations Group
1 mg of the desired additive. Weigh 51.8 mg of Tinuvin-P into
or equivalent.
the flask. Dissolve the components in 5 to 10 mL of warm
7.3 Computer System or Integrator coupled with the chro-
2-propanol. Transfer the solution mixture to a 1000-mL volu-
matograph is recommended to measure peak area.
metric flask and dilute to volume with 2-propanol.
7.4 Wiley Mill, equipped with a 20-mesh screen and water
11.2 Standardize the liquid chromatograph detector re-
cooled jacket to prevent thermodegradation of antioxidants
sponse by injection of 10 µL of the solution at the conditions
such as BHT and BHEB.
listed in 10.1.
7.5 Recorder, mv scale dependent upon the output of the
11.3 Measure the peak areas using a computer or an
detector.
integrator and calculate the relative response factor R as
7.6 Reflux Extraction Apparatus, consisting of a condenser
follows:
(24/40 ground glass joint), a flat bottom 125-mL flask having
conc. ~mg/L! additive 3 area Tinuvin2P
R 5 (1)
a 24/40 ground glass joint, and a hot plate. (SeeAppendix X1,
conc. ~mg/L! Tinuvin2P 3 area additive
Fig. X1.1.)
11.4 Average the response factors for three replicate injec-
7.7 Filter Systems (PTFE), for non-aqueous solutions (pore
tions of the calibration mixture.
size of 0.22 microns).
7.8 Analytical Balance, capable of weighing to 6 0.0001 g. NOTE 2—Tinuvin-P cannot be used as an internal standard when this
compound is expected as an additive in samples being analyzed.
8. Reagents and Materials
12. Sample Preparation
8.1 Tinuvin P,2(28hydroxy-58-methylphenyl)benzotriazole.
12.1 Grind the sample to a particle size of 20-mesh using a
8.2 2-Propanol:
water cooled Wiley mill.
8.2.1 2-Propanol T-P, HPLC grade, spectroquality or chro-
matography quality reagent 2-Propanol with 51.8 mg/L
NOTE 3—Grind7to8gofthesampletoruntheanalysis.Itisimportant
Tinuvin-P added as an internal standard. to minimize the time of grinding to prevent any thermodegradation of the
additives in the polymer.
8.2.2 2-Propanol, HPLC grade, spectroquality or chroma-
tography quality reagent.
12.2 Weigh 5 6 0.01 g of the sample into the flask, add a
8.3 Water, HPLC or UV quality reagent, degassed by
stirring bar, add by pipet 50.0 mL of 2-propanol solvent
spargingwithhighpurityheliumorbyfiltrationundervacuum.
containing the internal standard, and boil for 1 h (with stirring)
8.4 Acetonitrile, HPLC, spectroquality or ch
...
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