ASTM D5974-00(2010)

Standard Test Methods for Fatty and Rosin Acids in Tall Oil Fractionation Products by Capillary Gas Chromatography

SIGNIFICANCE AND USE
Tall oil fractionated products derived from tall oil are important commercial materials, primarily composed of fatty acids and rosin acids, but also containing some neutral material (see Terminology D804). For many applications, it is necessary to know the level of the individual fatty acids and rosin acids present in these products. Gas chromatography has proven to be a useful tool for such determinations (see Test Methods D509), and capillary chromatography, described in these test methods, is considered to be the most effective gas chromatographic technique currently available. In particular situations, other techniques may be more suitable than gas chromatography. For example, the presence of fatty acid esters in the sample would result in transesterification during the derivatization step that may affect the results.
Due to hydrogen bonding, unmodified tall oil fatty acids and rosin acids cannot be volatilized at atmospheric pressure without undergoing decomposition. So, it is necessary to convert the free acids to the more volatile and more stable methyl esters, prior to chromatographic separation.
These test methods describe four ways to prepare methyl esters. The classic method is through the use of diazomethane, but diazomethane is a hazardous and toxic material, and so is no longer the preferred agent. The use of diazomethane is detailed in the Appendix.
TMAH causes isomerization of a sample's di- and polyunsaturated fatty acids, when it is used in even a slight excess. This leads to inaccurate results for the individual fatty acid components. TMAH should be used for materials containing only rosin acids, or when the identification or quantitation of individual fatty acid components is not important.
TMPAH is the recommended methylating agent when the identification or quantitation of individual di- and polyunsaturated fatty acids is required. TMPAH produces results that are very similar to those of diazomethane, but without the hazards that are as...
SCOPE
1.1 These test methods cover the determination of the amounts of the individual fatty acids and rosin acids in fractionated tall oil products, using capillary gas chromatographic separation of the volatile methyl esters of these acids.
1.2 Four methods for forming the methyl esters, and two methods for determining the amounts of the individual fatty acids and rosin acids are described.
1.2.1 The classic method for the formation of methyl esters is through the use of diazomethane, but diazomethane is a hazardous and toxic material, and so is no longer the preferred reagent. The use of diazomethane is detailed in the Appendix. Methyl esters may be formed through the use of tetramethylammonium hydroxide (TMAH), trimethylphenylammonium hydroxide (TMPAH), or N,N-dimethylformamide dimethyl acetal (DMF-DMA).
1.2.2 The two methods for determining the amount of the individual fatty acids and rosin acids are the “internal standard” method, which yields absolute values, and the “area percent” method, which yields relative values.
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.

General Information

• Status: Historical
• Publication Date: 31-May-2010
• ICS: 67.080.10 - Fruits and derived products
• ICS: 67.200.10 - Animal and vegetable fats and oils
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.34 - Pine Chemicals and Hydrocarbon Resins

Relations

• Replaces: ASTM D5974-00(2005) - Standard Test Methods for Fatty and Rosin Acids in Tall Oil Fractionation Products by Capillary Gas Chromatography
• Effective Date: 01-Jun-2010
• Referred By: ASTM D803-15(2020) - Standard Test Methods for Testing Tall Oil
• Effective Date: 01-Jun-2010
• Referred By: ASTM D509-20 - Standard Test Methods of Sampling and Grading Rosin
• Effective Date: 01-Jun-2010

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: D5974 − 00(Reapproved 2010)
Standard Test Methods for
Fatty and Rosin Acids in Tall Oil Fractionation Products by
Capillary Gas Chromatography
This standard is issued under the fixed designation D5974; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 These test methods cover the determination of the
amounts of the individual fatty acids and rosin acids in
3. Significance and Use
fractionated tall oil products, using capillary gas chromato-
graphic separation of the volatile methyl esters of these acids.
3.1 Tall oil fractionated products derived from tall oil are
important commercial materials, primarily composed of fatty
1.2 Four methods for forming the methyl esters, and two
acidsandrosinacids,butalsocontainingsomeneutralmaterial
methods for determining the amounts of the individual fatty
(seeTerminologyD804).Formanyapplications,itisnecessary
acids and rosin acids are described.
to know the level of the individual fatty acids and rosin acids
1.2.1 The classic method for the formation of methyl esters
present in these products. Gas chromatography has proven to
is through the use of diazomethane, but diazomethane is a
be a useful tool for such determinations (see Test Methods
hazardous and toxic material, and so is no longer the preferred
D509), and capillary chromatography, described in these test
reagent. The use of diazomethane is detailed in theAppendix.
methods, is considered to be the most effective gas chromato-
Methyl esters may be formed through the use of tetramethyl-
graphic technique currently available. In particular situations,
ammonium hydroxide (TMAH), trimethylphenylammonium
other techniques may be more suitable than gas chromatogra-
hydroxide (TMPAH), or N,N-dimethylformamide dimethyl
phy. For example, the presence of fatty acid esters in the
acetal (DMF-DMA).
sample would result in transesterification during the derivati-
1.2.2 The two methods for determining the amount of the
zation step that may affect the results.
individualfattyacidsandrosinacidsarethe“internalstandard”
method, which yields absolute values, and the “area percent”
3.2 Duetohydrogenbonding,unmodifiedtalloilfattyacids
method, which yields relative values.
and rosin acids cannot be volatilized at atmospheric pressure
1.3 This standard does not purport to address all of the
without undergoing decomposition. So, it is necessary to
safety concerns, if any, associated with its use. It is the
convert the free acids to the more volatile and more stable
responsibility of the user of this standard to establish appro-
methyl esters, prior to chromatographic separation.
priate safety and health practices and determine the applica-
3.3 These test methods describe four ways to prepare
bility of regulatory limitations prior to use.
methyl esters. The classic method is through the use of
diazomethane, but diazomethane is a hazardous and toxic
2. Referenced Documents
material, and so is no longer the preferred agent. The use of
2.1 ASTM Standards:
diazomethane is detailed in the Appendix.
D509Test Methods of Sampling and Grading Rosin
3.3.1 TMAH causes isomerization of a sample’s di- and
D804Terminology Relating to Pine Chemicals, Including
polyunsaturated fatty acids, when it is used in even a slight
Tall Oil and Related Products
excess. This leads to inaccurate results for the individual fatty
acidcomponents.TMAHshouldbeusedformaterialscontain-
ing only rosin acids, or when the identification or quantitation
These test methods are under the jurisdiction of ASTM Committee D01 on
of individual fatty acid components is not important.
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.34 on Pine Chemicals and Hydrocarbon
3.3.2 TMPAH is the recommended methylating agent when
Resins.
the identification or quantitation of individual di- and polyun-
Current edition approved June 1, 2010. Published June 2010. Originally
saturated fatty acids is required. TMPAH produces results that
approved in 1996. Last previous edition approved in 2005 as D5974–00(2005).
DOI: 10.1520/D5974-00R10.
are very similar to those of diazomethane, but without the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
hazards that are associated with diazomethane.Aconsiderable
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
excess of TMPAH may cause isomerization of conjugated
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. compounds similar to that encountered with TMAH.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5974 − 00 (2010)
3.3.3 DMF-DMA gives results comparable to TMPAH and titrated with the acetic acid in methanol solution to the end
is easy and safe to use. However, the reagent is moisture point. When the solution is injected into the heated injection
sensitive, requiring samples to be free of any significant levels port of the chromatograph, the tetramethylammonium salts are
of water. pyrolyzed to methyl esters.
3.4 Two test methods for calculating the amounts of the
NOTE 2—For solid rosin, or other samples that are difficult to dissolve,
2 to 3 drops of toluene may be added to the vial prior to the addition of
individual fatty acid and rosin acid methyl esters are included
TMAH, to assist in dissolving the sample.
in these test methods. When the actual weight percentage of a
given compound is required, the “internal standard” method
5. Conversion By Means of Trimethylphenylammonium
mustbeused.Thismethodinvolvesaddingaknownamountof
Hydroxide (TMPAH)
an internal standard to a known amount of test material, and
5.1 Apparatus:
comparing the area of the peak associated with the internal
5.1.1 Standard Laboratory Equipment.
standard with the area of the peak of the individual fatty acid
or rosin acid methyl esters. The “area percent” method will
5.2 Reagents and Materials:
give the relative amount of each component, by comparing the
5.2.1 Purity of Reagents, see 4.2.1.
area of the appropriate peak to the total area of all peaks.
5.2.2 Trimethylphenylammonium Hydroxide Solution,0.2M
Non-eluting compounds will lead to erroneous (absolute)
or 0.1 M in methanol, CAS No. 1899-02-1.
results with this method.
5.2.3 Diethyl Ether, anhydrous.
5.2.4 Methanol, anhydrous.
PREPARATION OF METHYL ESTERS
5.2.5 Toluene, optional.
NOTE1—Anyofthesethreemethodscanbeused,withthechoicebeing
5.3 Procedure:
dependent on the factors mentioned in 3.3.
5.3.1 Add 0.5 to 3.0 mL of a 50:50 ether/methanol, to the
samplefrom9.2.2or17.1.Add2to3dropsofphenolphthalein
4. Conversion By Means of Tetramethylammonium
indicator solution and titrate to the very first permanent pink
Hydroxide (TMAH)
color with the TMPAH in methanol solution. When the
4.1 Apparatus:
solution is injected into the heated injection port of the
4.1.1 Standard Laboratory Equipment.
chromatograph, the trimethylphenylammonium salts are pyro-
lyzed to their respective methyl esters.
4.2 Reagents and Materials:
4.2.1 Purity of Reagents—Reagent grade chemicals shall be
NOTE 3—For solid rosin, or other samples that are difficult to dissolve,
used in all tests. Unless otherwise indicated, it is intended that
2 to 3 drops of toluene may be added to the vial prior to the addition of
all reagents shall conform to the specifications of the Commit-
TMPAH, to assist in dissolving the sample.
teeonAnalyticalReagentsoftheAmericanChemicalSociety ,
6. Conversion by Means of N,N-Dimethylformamide
where such specifications are available. Other grades may be
Dimethyl Acetal (DMF-DMA)
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
6.1 Apparatus:
accuracy of the determination.
6.1.1 Standard Laboratory Equipment.
4.2.2 Tetramethylammonium Hydroxide Solution, 24% in
6.2 Reagents and Materials:
methanol, CAS No. 75-59-2.
6.2.1 Purity of Reagents, see 4.2.1.
4.2.3 Tetramethylammonium Hydroxide Solution, 6% (v/v)
6.2.2 N,N-Dimethylformamide dimethyl acetal (DMF-
in methanol. Dilute 25 mL of the reagent described in 4.2.2
DMA), CAS No. 4637-24-5.
with 75 mL of methanol.
6.2.3 Methanol, anhydrous.
4.2.4 Phenolphthalein Solution, 1% (w/v) in methanol.
6.2.4 Toluene.
4.2.5 Diethyl Ether, anhydrous.
6.3 Procedure:
4.2.6 Methanol, anhydrous.
6.3.1 Place the sample from 9.2.2 or 17.1 in an appropriate
4.2.7 Acetic Acid, 5% volume/volume (v/v) in methanol.
anhydrous vial, and dissolve with approximately 0.5 mL of
4.2.8 Toluene, optional.
either methanol or toluene. Add approximately 1 mL of
4.3 Procedure:
DMF-DMA,mixwell,andmaintainthesampleat30–40°Cfor
4.3.1 Dissolve the sample from 9.2.2 or 17.1 in 0.5 to 3.0
15 minutes.
mL of a 50:50 ether/methanol mixture, add 2 to 3 drops of
phenolphthalein indicator solution, and titrate to a pH of 7.8 to
INTERNAL STANDARD METHOD
8.1 or to the very first permanent pink color, with the 6%
7. Apparatus
solutionofTMAH.Ifthesolutionisovertitrated,itcanbeback
7.1 Gas Chromatograph—An instrument equipped with a
flame ionization detector (FID) that can be operated at condi-
Reagent Chemicals, American Chemical Society Specifications, American
tions given in 10.1.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
7.2 Column—A high resolution column between 15 and 60
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
minlength,0.25to0.53mminternaldiameter,witha0.20-µm
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. film thickness of biscyanopropylsiloxane type liquid phase.
D5974 − 00 (2010)
NOTE 1—Labeled peaks are eluted as methyl esters.
FIG. 1 Typical Chromatogram of Distilled Tall Oil
to ensure the results are not affected by air oxidation of the rosin.
The recommended referee column is 30 m in length, 0.32 mm
internal diameter, with a 0.20-µm film thickness, and provides
9.2.2 Convert the test sample to methyl esters or substituted
separations equivalent or better than that displayed in Fig. 1.
ammonium salts, as described in Sections 4, 5, 6.
NOTE 4—When using this method for referee purposes, verify that the
10. Set-up of Gas Chromatograph (GC)
resolution is adequate and comparable to that shown in Fig. 1.
10.1 Set the GC conditions so that they are approximately
7.3 Analytical Balance, accurate to 0.1 mg.
(see Note 7) as follows:
8. Reagents and Materials
Column temperature (oven temperature)
Initial 150°C
8.1 Purity of Reagents, see 4.2.1.
Hold 5 min
Ramp 5°C/min
8.2 Myristic Acid (Internal Standard), 99% pure.
Final 250°C
NOTE 5—A higher molecular-weight saturated fatty acid that elutes as Hold 10 min
Injection port temperature 300°C
a methyl ester later in the chromatogram may be used in place of, or in
Injection port liner glass split
addition to myristic acid, provided that the alternative internal standard
Detector temperature 325°C
peak does not coelute with sample component peaks.
Carrier gas helium
Linear gas velocity 19.5–20.5 cm/s
8.3 Stearic Acid, Oleic Acid, Linoleic Acid, Abietic Acid,
Split ratio 100 to 1 maximum
and Dehydroabietic Acid—Other high purity reference stan-
Detector FID
dards can be added as needed.
Hydrogen 30 mL/min
Air 400 mL/min
Makeup gas 30 mL/min
9. Procedure
NOTE 7—These are typical operating conditions only. The individual
9.1 Preparation of Calibration Standard:
instrument should be adjusted in accordance with manufacturer’s instruc-
9.1.1 Accurately weigh into a suitable vial, milligram quan-
tions to optimize desired performance. Ongoing adjustments in operating
tities of the myristic acid internal standard, plus the fatty acid
temperature and flow rate may be necessary to maintain optimum
and rosin acid standards that are anticipated to be in the test
performance of the column due to aging.
sample, and record the weights.
10.2 Calibration:
9.1.2 Convert the calibration standard to the methyl esters
10.2.1 Inject 0.5 to 1.0 µL of the appropriate standard
or substituted ammonium salts as described in Sections 4, 5, 6.
prepared in 9.1.
9.2 Preparation of Test Sample:
10.2.2 Record the retention time and calculate the indi-
9.2.1 Accurately weigh ;50 mg of sample and ;15 mg of
vidual relative response factors as follows:
myristicaciddirectlyintoasuitablevialandrecordtheweight.
W A
i IS
RRF 5 3 (1)
i
NOTE 6—Rosin samples need to be freshly broken from a larger mass A W
i IS
D5974 − 00 (2010)
TABLE 1 Precision of Internal Standard Method
Repeatability Repeatability Reproducibility Reproducibility
Limit, 95 % Standard Deviation Limit, 95 % Standard Deviation
TOFA Material
Stearic acid 0.6 0.2 0.8 0.3
Oleic acid 7.6 2.7 10.4 3.7
Linoleic acid 5.0 1.8 7.3 2.6
DTO Material
Stearic acid 0.2 0.09 0.6 0.2
Oleic acid 1.4 0.5 1.7 0.6
Linoleic acid 1.1 0.4 1.4 0.5
Abietic acid 0.6 0.2 0.8 0.3
Dehydroabietic acid 0.3 0.1 0.8 0.3
ROSIN Material
Abietic acid 6.4 2.3 10.6 3.8
Dehydroabietic acid 2.0 0.7 2.8 1.0
where: oilfattyacids(TOFA),DTO,androsinwasrunin1995bynine
laboratories. The design of the experiment, similar to that of
RRF = relative response factor of individual fatty or rosin
I
Practice E691, and a within-between analysis of the data are
acid methyl esters,
given in ASTM Research Report.
W = weightofindividualfattyorrosinacidmethylesters
I
14.1.1 Test Result—The precision information given in
in standard, W = weight used × purity,
i
Table 1 for fatty and rosin acids is for the comparison of two
A = peak area of individual fatty or rosin acid,
I
A = peak area of internal standard, and test results.
IS
W = weight of internal standard. W = weight used ×
IS IS
NOTE11—Repeatability=withinlaboratory,Reproducibility=between
purity.
laboratories.
NOTE 8—For highest accuracy, the purity of the standards should be
14.1.2 Bias—Since there is no accepted reference material,
used to correct the weight terms.
method or laboratory suitable for determining the bias for the
11. Analysis
procedure in this test method for measuring component
concentration, no statement on bias is being made.
11.1 Inject0.5to1.0µLofthetestsamplepreparedin9.2.2.
NOTE 9—Dilution of the sample with additional solvent may be
AREA PERCENT METHOD
necessarytoobtaininj
...