ASTM G120-95(2001)
(Practice)Standard Practice for Determination of Soluble Residual Contamination in by Soxhlet Extraction
Standard Practice for Determination of Soluble Residual Contamination in by Soxhlet Extraction
SCOPE
1.1 This practice describes a procedure for the determination of residual contamination in systems and components requiring a high level of cleanliness, such as oxygen, by Soxhlet extraction.
1.2 This practice may be used for extracting nonvolatile and semivolatile residues from solids such as new and used gloves, new and used wipes, contaminated test specimens or control coupons, small pieces of hardware, component softgoods, etc. When used with proposed cleaning materials (wipes, gloves, etc.), this practice may be used to determine the potential of the proposed solvent to extract contaminants (plasticizers, residual detergents, brighteners, etc.) and deposit them on the surface being cleaned.
1.3 This practice is not suitable for the evaluation of particulate contamination.
1.4 The values stated in SI units are standard. Values in parentheses are for information only.
1.5 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.
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Designation: G 120 – 95 (Reapproved 2001)
Standard Practice for
Determination of Soluble Residual Contamination in
Materials and Components by Soxhlet Extraction
This standard is issued under the fixed designation G 120; 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 Equipment Used in Oxygen-Enriched Environments
1.1 This practice describes a procedure for the determina-
3. Terminology
tion of residual contamination in systems and components
3.1 Definitions:
requiring a high level of cleanliness, such as oxygen, by
3.1.1 contaminant, n—unwanted molecular and particulate
Soxhlet extraction.
matter that could affect or degrade the performance of the
1.2 This practice may be used for extracting nonvolatile and
components upon which they reside.
semivolatile residues from solids such as new and used gloves,
3.1.2 contamination, n—a process of contaminating.
new and used wipes, contaminated test specimens or control
3.1.3 nonvolatile residue (NVR), n—residual molecular and
coupons, small pieces of hardware, component softgoods, etc.
particulate matter remaining following the filtration of a
When used with proposed cleaning materials (wipes, gloves,
solvent containing contaminants and complete evaporation of
etc.), this practice may be used to determine the potential of the
the solvent at a specified temperature.
proposed solvent to extract contaminants (plasticizers, residual
3.1.4 particle (particulate contaminant), n— a piece of
detergents, brighteners, etc.) and deposit them on the surface
matter in a solid state with observable length, width, and
being cleaned.
thickness.
1.3 This practice is not suitable for the evaluation of
3.1.4.1 Discussion—The size of a particle is usually defined
particulate contamination.
by its greatest dimension and is specified in micrometres.
1.4 The values stated in SI units are standard. Values in
3.1.5 molecular contaminant (non-particulate contamina-
parentheses are for information only.
tion), n—the molecular contaminant may be in a gaseous,
1.5 This standard does not purport to address all of the
liquid, or solid state.
safety concerns, if any, associated with its use. It is the
3.1.5.1 Discussion—It may be uniformly or nonuniformly
responsibility of the user of this standard to establish appro-
distributed, or be in the form of droplets. Molecular contami-
priate safety and health practices and determine the applica-
nants account for most of the NVR.
bility of regulatory limitations prior to use.
3.1.6 control coupon (witness coupon), n— a coupon made
2. Referenced Documents from the same material and prepared in exactly the same way
as the test coupons, which is used to verify the validity of the
2.1 ASTM Standards:
method or part thereof.
D 1193 Specification for Reagent Water
3.1.6.1 Discussion—In this test method, the control coupon
E 1235 Test Method for Gravimetric Determination of Non-
will be contaminated in the same manner as the test coupons
volatile Residue (NVR) in Environmentally Controlled
and will be subjected to the identical extraction procedure.
Areas for Spacecraft
F 324 Test Method for Nonvolatile Residue of Volatile
4. Summary of Practice
Cleaning Solvents Using the Solvent Purity Meter
4.1 The sample is placed in an extraction thimble or
F 331 Test Method for Nonvolatile Residue of Solvent
between two plugs of glass wool and extracted using an
Extract from Aerospace Components (Using Rotary Flash
3 appropriate solvent (see Practice G 93 for recommendations) in
Evaporator)
a Soxhlet extractor. The solvent is brought to the boiling point;
G 93 Practice for Cleaning Methods for Material and
the pure solvent vapors travel to the condenser where they
condense and drip into the thimble. When the liquid level in the
This practice is under the jurisdiction of ASTM Committee G04 on Compat-
thimble reaches the top of the Soxhlet siphon, the solvent and
ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the
extracted soluble contaminant are siphoned back into the
direct responsibility of Subcommittee G04.01 on Test Methods.
boiler. This process is allowed to continue for several hours.
Current edition approved Oct. 10, 1995. Published November 1995. Originally
published as G120 – 93. Last previous edition G 120 – 93.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 15.03.
Discontinued: see 1986 Annual Book of ASTM Standards, Vol 10.05.
Annual Book of ASTM Standards, Vol 14.04.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G 120
The solvent and extract are then concentrated or dried for
analysis.
5. Significance and Use
5.1 It is expected that this test method will be suitable to
identify and quantify contaminants found in systems, system
materials, and components used in systems requiring a high
level of cleanliness, such as oxygen. Softgoods such as seals
and valve seats can be tested as received. Gloves and wipes, or
samples thereof, to be used in the cleaning operation can be
evaluated prior to use to ensure that the proposed cleaning
solvent does not extract and deposit chemicals on the surface to
be cleaned.
5.2 Wipes or other cleaning equipment can be tested after
use to determine the amount of contaminant removed from a
surface. This procedure can be used to obtain samples for NVR
analysis using contaminated control coupons that were sub-
jected to the cleaning process as controls to validate cleaning
operations.
5.3 The selection of the solvent requires some knowledge of
the contaminant. If a nonvolatile residue (NVR) analysis is to
be performed on the molecular contaminant, the boiling point
of the solvent shall be significantly lower than that of the
contaminant. For other analytical methods, the tester must
know the accuracy of the analytical methods, and the solvent
shall be chosen so as not to interfere with the selected
analytical method. To identify the composition of the NVR,
analytical methods such as infrared spectroscopy or gas
chromatography/mass spectroscopy have been used satisfacto-
rily.
FIG. 1 Soxhlet Extraction Apparatus
6. Apparatus
6.1 Soxhlet extractor—500 mL evaporation flask and asso-
NOTE 1—Warning: Solvents such as 2-propanol and 2-butanone are
ciated equipment as shown in Fig. 1.
highly flammable. The reader should refer to appropriate safe handling
6.2 Boiling chips—solvent extracted.
procedures.
6.3 Water bath—heated with temperature control of 65°C.
7.3 Water—shall meet the requirements of D 1193, Type II.
6.4 Thimbles—glass or paper.
6.5 Heating mantle—rheostat controlled.
8. Procedure
6.6 Balance—range to a minimum of 50 g with an accuracy
8.1 Prepare the sample for placement in the extractor.
of 0.1 mg.
8.1.1 To determine the amount of extractable material in a
6.7 Evaporator—rotary.
wiping cloth (new or used), cut out a test section approximately
7. Reagents
30 centimetres (cm) square, accurately measure and calculate
the area (A) in square centimetres, and weigh the section in
7.1 Solvents that can be used to prepare standard contami-
nant solutions include the following: 2-propanol, 2-butanone, grams to the nearest
...
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