ASTM D4526-96

Standard Practice for Determination of Volatiles in Polymers by Static Headspace Gas Chromatography

SCOPE
1.1 Headspace gas chromatography (GC) involves the determination of volatile components in a polymer solution by gas chromatography of a vapor phase in thermal equilibrium with the sample matrix. Volatiles in finely ground insoluble polymers can also be determined with and without an extracting solvent.
1.2 This practice provides two procedures:
1.2.1 Procedure A--Automatic headspace analysis.
1.2.2 Procedure B--Manual injection headspace analysis.
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 6.
Note 1--There is no equivalent ISO standard.

General Information

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

Relations

• Replaced By: ASTM D4526-96(2001)e1 - Standard Practice for Determination of Volatiles in Polymers by Static Headspace Gas Chromatography
• Effective Date: 01-Jan-2001
• Referred By: ASTM D3749-19 - Standard Test Method for Residual Vinyl Chloride Monomer in Poly(Vinyl Chloride) Resins by Gas Chromatographic Headspace Technique
• 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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.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 4526 – 96
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 Practice for
Determination of Volatiles in Polymers by Static Headspace
Gas Chromatography
This standard is issued under the fixed designation D 4526; 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 For polymer analysis, sample treatment for headspace
analysis is simpler than conventional gas chromatography,
1.1 Headspace gas chromatography (GC) involves the de-
where precipitation steps may be required to prevent polymer
termination of volatile components in a polymer solution by
contamination of the chromatographic column.
gas chromatography of a vapor phase in thermal equilibrium
3.4 This headspace practice will be able to determine
with the sample matrix. Volatiles in finely ground insoluble
qualitatively any component with sufficient vapor pressure. It
polymers can also be determined with and without an extract-
is capable of yielding semiquantitative results and can be used
ing solvent.
for relative comparisons between samples.
1.2 This practice provides two procedures:
1.2.1 Procedure A—Automatic headspace analysis.
4. Apparatus
1.2.2 Procedure B—Manual injection headspace analysis.
4.1 Gas Chromatograph, equipped with an appropriate
1.3 This standard does not purport to address all of the
detector and backflush valve.
safety concerns, if any, associated with its use. It is the
4.1.1 For Procedure A, an Automated Headspace Sampler,
responsibility of the user of this standard to establish appro-
including backflush capability, thermostated sample tray, and
priate safety and health practices and determine the applica-
associated accessories fulfill these requirements while provid-
bility of regulatory limitations prior to use. Specific precau-
ing for automatic sequential sampling of headspace vapors.
tionary statements are given in Section 6.
4.1.2 Procedure B requires the following additional equip-
NOTE 1—There is no equivalent ISO standard.
ment:
4.1.2.1 Constant-Temperature Bath, capable of maintaining
2. Referenced Documents
90 6 1°C.
2.1 ASTM Standards:
4.1.2.2 Gas-Tight Gas Chromatographic Syringes, which
D 4322 Test Method for Residual Acrylonitrile Monomer in
can be heated to 90°C for sampling and injection.
Styrene-Acrylonytrile Copolymers and Nitrile Rubber by
4.1.2.3 Valve, 6-port for backflush assembly.
Headspace Gas Chromatography
NOTE 2—Appropriate detectors could include the following:
E 260 Practice for Packed Column Gas Chromatography
(a) Flame ionization (FID) for general organic volatiles,
E 355 Practice for Gas Chromatography Terms and Rela-
(b) Electron capture (EC) for halogenated species,
tionships
(c) Nitrogen-phosphorous (NPD) for acrylonitrile,
E 594 Practice for Testing Flame Ionization Detectors Used
(d) Thermal conductivity (TC) for water, and
in Gas Chromatography
(e) Hall electroconductivity or photoionization (PID) for vinyl chlo-
ride.
3. Significance and Use
4.2 Chromatographic Column—Common column pack-
3.1 For various reasons, one may want to measure the level 5
ings found to be useful for residual monomers (for example,
of unreacted or residual monomer, water, or other volatile
acrylonitrile, vinyl chloride) include Chromosorb or Porapak
components in a polymer sample.
porous polymer packings, 0.4 % Carbowax 1500 liquid phase
3.2 Volatiles of interest are often at trace concentrations.
on Carbopak C support, or 0.19 % picric acid on Carbopak C
Headspace analysis is suited for determination of these trace
support. Other columns can be used after it is determined that
components which often cannot be determined by conventional
they give the required resolution and accuracy for the compo-
gas chromatography because of sample decomposition or
nent of interest.
interferences.
4.3 Integrator, capable of measuring and storing peak area
data.
This practice is under the jurisdiction of ASTM Committee D-20 on Plastics
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Nov. 10, 1996. Published May 1997. Originally
e1 4
published as D 4526 – 85. Last previous edition D 4526 – 85 (1991) . Available from Perkin-Elmer Corp., Main Ave., Norwalk, CT 06856.
2 5
Annual Book of ASTM Standards, Vol 08.02. Available from Supelco, Inc., P.O. Box 628, 146 S. Water St., Bellefonte, PA
Annual Book of ASTM Standards, Vol 14.01. 16823.
D 4526
4.4 Headspace Vials, septa, ring closures, and vial sealer. attaining thermal equilibrium in a reasonable period of time.
4.5 Analytical Balance, capable of weighing to 60.0001 g. These samples are weighed (0.56 0.001 g) into headspace
4.6 Soap Film Flowmeter and Stopwatch, or other means of vials, then dissolved in 10 mL of an appropriate solvent. Using
measuring gas flow rates. ionization detection, these 5 % solutions provide sensitivity for
4.7 Pressure Regulators for all required gas cylinders. many volatiles at ppm levels. Sample size can be increased to
4.8 Filter-Dryer Assemblies for each required gas cylinder. attain sensitivity at lower levels.
NOTE 5—Freeze grinding polymer pellets or granules with liquid
5. Reagents and Materials
nitrogen and screening through a thirty-mesh screen often works as well
5.1 Solvent, Reagent Grade, or Best Available—The solvent
as testing powdered resin.
should be free of interferences at the retention time of volatile
NOTE 6—This technique of sample preparation requires analysis of the
compounds determined by this technique. Typical polymer solvent blank to ensure freedom from interferences at volatile component
retention times.
solvents include water, dimethylformamide (DMF), dimethy-
NOTE 7—Increased sample sizes can result in viscous solutions. Warm-
lacetamide (DMAC), propylene carbonate, and
ing these solutions is often necessary to ensure complete sample dissolu-
o-dichlorobenzene. These solvents are readily backflushed
tion.
from most chromatographic columns
...