ASTM D2549-02(2017)
(Test Method)Standard Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography
Standard Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography
SIGNIFICANCE AND USE
5.1 The determination of compound types by mass spectrometry requires, in some instances, a preliminary separation of the petroleum sample into representative aromatics and nonaromatics fractions, as in Test Methods D2425, D2786, and D3239. This test method provides a suitable separation technique for this application.
SCOPE
1.1 This test method covers the separation and determination of representative aromatics and nonaromatics fractions from hydrocarbon mixtures that boil between 232 °C and 538 °C (450 °F and 1000 °F). Alternative procedures are provided for the separation of 2 g or 10 g of hydrocarbon mixture.
Note 1: Some components may not be eluted from the chromatographic column for some types of samples under the conditions used in this method.
Note 2: Test Method D2007 is an alternative method of separating high-boiling oils into polar compounds, aromatics, and saturates fractions.
1.2 An alternative procedure is provided to handle samples boiling below 232 °C (450 °F), but whose 5 % point is above 178 °C (350 °F) as determined by Test Method D2887. This procedure is given in Appendix X1.
1.3 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Buy Standard
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D2549 − 02 (Reapproved 2017)
Standard Test Method for
Separation of Representative Aromatics and Nonaromatics
Fractions of High-Boiling Oils by Elution Chromatography
This standard is issued under the fixed designation D2549; 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 D2007 Test Method for Characteristic Groups in Rubber
Extender and Processing Oils and Other Petroleum-
1.1 This test method covers the separation and determina-
Derived Oils by the Clay-Gel Absorption Chromato-
tion of representative aromatics and nonaromatics fractions
graphic Method
from hydrocarbon mixtures that boil between 232 °C and
D2425 Test Method for Hydrocarbon Types in Middle Dis-
538 °C (450 °F and 1000 °F). Alternative procedures are pro-
tillates by Mass Spectrometry
vided for the separation of 2 g or 10 g of hydrocarbon mixture.
D2786 Test Method for Hydrocarbon Types Analysis of
NOTE 1—Some components may not be eluted from the chromato-
Gas-Oil Saturates Fractions by High Ionizing Voltage
graphic column for some types of samples under the conditions used in
Mass Spectrometry
this method.
D2887 Test Method for Boiling Range Distribution of Pe-
NOTE 2—Test Method D2007 is an alternative method of separating
troleum Fractions by Gas Chromatography
high-boiling oils into polar compounds, aromatics, and saturates fractions.
D3239 Test Method for Aromatic Types Analysis of Gas-Oil
1.2 An alternative procedure is provided to handle samples
Aromatic Fractions by High Ionizing Voltage Mass Spec-
boiling below 232 °C (450 °F), but whose 5 % point is above
trometry
178 °C (350 °F) as determined by Test Method D2887. This
procedure is given in Appendix X1.
3. Terminology
1.3 The values stated in acceptable SI units are to be
3.1 Definitions of Terms Specific to This Standard:
regarded as the standard. The values given in parentheses are
3.1.1 aromatics fraction—the portion of the sample des-
provided for information purposes only.
orbed with the polar eluants. The aromatics fraction may
contain aromatics, condensed naphthenic-aromatics, aromatic
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the olefins, and compounds containing sulfur, nitrogen, and oxy-
gen atoms.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.1.2 nonaromatics fraction—the portion of the sample
mine the applicability of regulatory limitations prior to use.
eluted with n-pentane. The nonaromatics fraction is a mixture
1.5 This international standard was developed in accor-
of paraffinic and naphthenic hydrocarbons if the sample is a
dance with internationally recognized principles on standard-
straight-run material. If the sample is a cracked stock, the
ization established in the Decision on Principles for the
nonaromatics fraction will also contain aliphatic and cyclic
Development of International Standards, Guides and Recom-
olefins.
mendations issued by the World Trade Organization Technical
4. Summary of Test Method
Barriers to Trade (TBT) Committee.
4.1 A weighed amount of sample is charged to the top of a
2. Referenced Documents
glass chromatographic column packed with activated bauxite
and silica gel. n-Pentane is added to the column to elute the
2.1 ASTM Standards:
nonaromatics. When all of the nonaromatics are eluted, the
aromatics fraction is eluted by additions of diethyl ether,
This test method is under the jurisdiction of ASTM Committee D02 on chloroform, and ethyl alcohol.
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
4.2 The solvents are completely removed by evaporation,
Subcommittee D02.04.0C on Liquid Chromatography.
and the residues are weighed and calculated as the aromatics
Current edition approved Dec. 1, 2017. Published December 2017. Originally
approved in 1966. Last previous edition approved in 2012 as D2549 – 02 (2012).
and nonaromatics fractions of the sample.
DOI: 10.1520/D2549-02R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5. Significance and Use
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1 The determination of compound types by mass spec-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. trometry requires, in some instances, a preliminary separation
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2549 − 02 (2017)
FIG. 1 Chromatographic Columns
of the petroleum sample into representative aromatics and 6.4 Electric Vibrator, for packing column.
nonaromatics fractions, as in Test Methods D2425, D2786, and
6.5 Weighing Bottles or Erlenmeyer Flasks, 25 mL and
D3239. This test method provides a suitable separation tech-
50 mL.
nique for this application.
7. Reagents and Materials
6. Apparatus
7.1 Purity of Reagents—Reagent grade chemicals shall be
6.1 Chromatographic Columns, as shown in Fig. 1. Differ-
used in this test. Unless otherwise indicated, it is intended that
ent chromatographic columns are provided for the analysis of
all reagents shall conform to the specifications of the Commit-
2 g and 10 g samples.
tee on Analytical Reagents of the American Chemical Society,
where such specifications are available. Other grades may be
6.2 Beakers, 100 mL, 250 mL, and 600 mL, inverted-rim
used, provided it is first ascertained that the reagent is of
type.
sufficiently high purity to permit its use without lessening the
6.3 Steam Bath.
accuracy of the determination.
3 4
The sole source of supply of the beakers known to the committee at this time Reagent Chemicals, American Chemical Society Specifications, American
is Kontes Glass Co., Vineland, NJ; order “Anti-Creep” beakers and refer to Drawing Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
No. 9413-A. If you are aware of alternative suppliers, please provide this listed by the American Chemical Society, see Annual Standards for Laboratory
information to ASTM International Headquarters. Your comments will receive Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
careful consideration at a meeting of the responsible technical committee , which and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
you may attend. MD.
D2549 − 02 (2017)
7.2 Bauxite, 20 mesh to 60 mesh. Before use, activate the 8.4 If 2 g of sample are to be analyzed, continue as in 8.4.1,
bauxite by heating at 538 °C (1000 °F) for 16 h. Transfer the otherwise continue as in 8.5.
activated material to an airtight container while still hot and 8.4.1 If the sample is viscous, warm it with intermittent
protect thereafter from atmospheric moisture. mixing or shaking until it is completely fluid. Transfer a
representative sample (approximately 2 g) to a 25 mL weigh-
7.3 Chloroform. (Warning—Toxic. May be fatal if swal-
ing bottle or flask. Determine the mass of the sample to the
lowed.)
nearest 1 mg by weighing the flask before and after sample
7.4 Cleaning Solution—Chromic-sulfuric acid. (Warning—
transfer. Add 10 mL of n-pentane (Warning—Extremely flam-
Causes severe burns. A recognized carcinogen, strong oxidizer,
mable liquid), to the flask and dissolve the sample. If the
contact with organic material may cause fire.)
sample does not dissolve completely in cold n-pentane, warm
7.5 Diethyl Ether, anhydrous. (Warning—Extremely flam- it in warm water or over a steam bath. If the sample does not
dissolve in warm n-pentane, take a fresh sample and substitute
mable.) The ethyl ether used in this test method should be free
of peroxides as determined by the procedure in “Reagent cyclohexane for the n-pentane.
Chemical, American Chemical Society Specifications.” 8.4.2 Add 10 mL of n-pentane to the top of the column to
prewet the adsorbent. When the liquid level reaches the top of
7.6 Ethyl Alcohol, denatured, conforming to Formula 2B of
the bauxite bed, transfer the sample solution from the weighing
the U.S. Bureau of Internal Revenue. (Warning—Flammable.)
flask to the top of the column. Rinse the flask with three
7.7 Pressuring Gas, dry air or nitrogen, delivered to the top
successive 3 mL washes of n-pentane. Add each wash to the
of the column at a regulated gage pressure of 0 psi to 2 psi
top of the column. Then rinse the walls of the column bulb with
(13.8 kPa). (Warning—Compressed gas.)
two 3 mL portions of n-pentane, allowing the liquid level to
7.8 n-Pentane, commercial grade, aromatic-free. Some reach the top of the bauxite bed before adding the next portion.
Finally add 35 mL of n-pentane to the column bulb.
samples of waxy stocks may not dissolve completely in
n-pentane, in which case cyclohexane, commercial grade, 8.4.3 Place a 50 mL graduate beneath the column to collect
the eluate. The elution rate should be approximately 1 mL ⁄min.
aromatic-free, may be substituted for n-pentane. (Warning—
Extremely flammable liquid.)
NOTE 4—Gas pressure (Warning—Compressed gas) can be applied to
the top of the column as necessary to maintain the elution rate at
7.9 Silica Gel, 100 mesh to 200 mesh.
approximately 1 mL ⁄min. If the correct pressure setting is known from
8. Procedure previous runs, gas pressure may be applied after addition of the last
increment of n-pentane. Otherwise, gas pressure should be applied when
NOTE 3—The procedural details differ depending on the initial boiling
n-pentane begins to elute from the column and should be adjusted to give
point of the sample. If the 5 % point is above 178 °C (350 °F), but below
a flow rate of approximately 1 mL ⁄min.
232 °C (450 °F), use procedure described in Appendix X1. If above
232 °C, continue as written depending on amount of sample to be
8.4.4 When the n-pentane level reaches the top of the
analyzed. Instructions specific for 2 g samples are given in 8.4.1 – 8.4.13,
bauxite bed, add 80 mL of diethyl ether (Warning—Extremely
and instructions specific for 10 g samples are given in 8.5.1 and 8.5.8.
flammable). Connect the pressuring gas to the top of the
8.1 Select the appropriate column, depending on whether
column and adjust the pressure to maintain an elution rate of
2 g or 10 g of sample are to be analyzed. Clean the column
1 mL ⁄min to 2 mL ⁄min.
with chromic-sulfuric acid (Warning—Causes severe burns),
8.4.5 Collect 50 mL of n-pentane eluate in the graduate.
followed by distilled or demineralized water, acetone, and dry
Rinse the tip of the column with 1 mL to 2 mL of n-pentane,
air or nitrogen.
adding this to the 50 mL in the graduate (Note 5). Label the
8.2 Introduce a small plug of glass wool into the column,
50 mL graduate as n-pentane eluate.
pressing it firmly into the lower end to prevent the flow of silica
NOTE 5—The n-pentane will have reached the adsorbent bed before the
gel from the column.
required volume of eluate has been collected in the 50 mL receiver.
Continue collection in this receiver after the addition of ether until the
8.3 Clamp the column in a vertical position. Add small
proper volume has been collected before changing to the 100 mL
increments of silica gel, while vibrating the column along its
graduate.
length, until the tightly packed silica gel extends to the lower
8.4.6 When the ether level reaches the top of the bauxite
mark on the chromatographic column. Continue to vibrate the
bed, release the gas pressure and add 100 mL of chloroform
column and add bauxite until the bauxite layer extends to the
(Warning—Toxic. May be fatal if swallowed) to the top of the
upper mark on the chromatographic column. Vibrate the
column. Reconnect the gas pressuring system and continue the
column for an additional 3 min after filling is completed.
elution. When 80 mL of eluate have been collected in the
5 graduate, rinse the column tip with 1 mL of ether and add the
The sole source of supply of the bauxite known to the committee at this time
is Porocel Corp., Little Rock, AR. If you are aware of alternative suppliers, please rinse to the 100 mL graduate. Change the receiver to a 250 mL
provide this information to ASTM International Headquarters. Your comments will
graduate. Label the 100 mL graduate as ether-eluted fraction.
receive careful consideration at a meeting of the responsible technical committee ,
8.4.7 When the chloroform level reaches the top of the
which you may attend.
bauxite bed, release the gas pressure and add 75 mL of ethyl
The sole source of supply of the silica gel known to the committee at this time
is W.R. Grace and Co., Davison Chemical Div., Baltimore, MD 21203, by
alcohol (Warning—Flammable liquid). Reconnect the gas
specifying Code 923. If you are aware of alternative suppliers, please provide this
pressuring system and continue the elution until the alcohol
information to ASTM International Headquarters. Your comments will receive
1 level reaches the top of the bauxite bed. Release the gas
careful consideration at a meeting of the responsible technical committee , which
you may attend. pressure. Rinse the column tip with 1 mL of chloroform adding
D2549 − 02 (2017)
this to the graduate. Label the 250 mL graduate as chloroform- the bauxite bed before adding the next portion. Finally add
alcohol-eluted fraction. 70 mL of n-pentane to the column bulb.
8.5.3 Place a 200 mL graduate beneath the column to collect
8.4.8 Weigh a 100 mL inverted-rim beaker to the nearest
1 mg. Quantitatively transfer the n-pentane eluate to this the eluate. The elution rate should be approximately 3 mL ⁄min.
beaker and allow the n-pentane to evaporate at room tempera-
NOTE 7—Air or nitrogen pressure may be applied to the top of the
ture. Cyclohexane, if used as the elution solvent, is evaporated
column as necessary to accomplish and maintain a satisfactory elution
on a steam bath. Evaporation is accelerated in both cases by
rate. Three to five pounds of pressure generally is sufficient. If the correct
pressure setting is known from previous runs, gas pressure can be applied
directing a controlled stream of dry nitrogen downward onto
after addition of the last increment of n-pentane. Otherwise, gas pressure
the surface of the liquid.
should be applied when n-pentane begins to elute from the column and
8.4.9 When all the solvent appears to be evaporated, stop
should be adjusted to give a flow rate of
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2549 − 02 (Reapproved 2012) D2549 − 02 (Reapproved 2017)
Standard Test Method for
Separation of Representative Aromatics and Nonaromatics
Fractions of High-Boiling Oils by Elution Chromatography
This standard is issued under the fixed designation D2549; 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
1.1 This test method covers the separation and determination of representative aromatics and nonaromatics fractions from
hydrocarbon mixtures that boil between 232232 °C and 538°C (450538 °C (450 °F and 1000°F).1000 °F). Alternative procedures
are provided for the separation of 2 g or 10 g 2 g or 10 g of hydrocarbon mixture.
NOTE 1—Some components may not be eluted from the chromatographic column for some types of samples under the conditions used in this method.
NOTE 2—Test Method D2007 is an alternative method of separating high-boiling oils into polar compounds, aromatics, and saturates fractions.
1.2 An alternative procedure is provided to handle samples boiling below 232°C (450°F),232 °C (450 °F), but whose 5 % point
is above 178°C (350°F)178 °C (350 °F) as determined by Test Method D2887. This procedure is given in Appendix X1.
1.3 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided
for information purposes only.
1.4 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 safety, health, and healenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D2007 Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils by the
Clay-Gel Absorption Chromatographic Method
D2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry
D2786 Test Method for Hydrocarbon Types Analysis of Gas-Oil Saturates Fractions by High Ionizing Voltage Mass
Spectrometry
D2887 Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
D3239 Test Method for Aromatic Types Analysis of Gas-Oil Aromatic Fractions by High Ionizing Voltage Mass Spectrometry
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 aromatics fraction—the portion of the sample desorbed with the polar eluants. The aromatics fraction may contain
aromatics, condensed naphthenic-aromatics, aromatic olefins, and compounds containing sulfur, nitrogen, and oxygen atoms.
3.1.2 nonaromatics fraction—the portion of the sample eluted with n-pentane. The nonaromatics fraction is a mixture of
paraffinic and naphthenic hydrocarbons if the sample is a straight-run material. If the sample is a cracked stock, the nonaromatics
fraction will also contain aliphatic and cyclic olefins.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0C on Liquid Chromatography.
Current edition approved April 15, 2012Dec. 1, 2017. Published April 2012December 2017. Originally approved in 1966. Last previous edition approved in 20072012
as D2549–02(2007).D2549 – 02 (2012). DOI: 10.1520/D2549-02R12.10.1520/D2549-02R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2549 − 02 (2017)
FIG. 1 Chromatographic Columns
4. Summary of Test Method
4.1 A weighed amount of sample is charged to the top of a glass chromatographic column packed with activated bauxite and
silica gel. n-Pentane is added to the column to elute the nonaromatics. When all of the nonaromatics are eluted, the aromatics
fraction is eluted by additions of diethyl ether, chloroform, and ethyl alcohol.
4.2 The solvents are completely removed by evaporation, and the residues are weighed and calculated as the aromatics and
nonaromatics fractions of the sample.
5. Significance and Use
5.1 The determination of compound types by mass spectrometry requires, in some instances, a preliminary separation of the
petroleum sample into representative aromatics and nonaromatics fractions, as in Test Methods D2425, D2786, and D3239. This
test method provides a suitable separation technique for this application.
6. Apparatus
6.1 Chromatographic Columns, as shown in Fig. 1. Different chromatographic columns are provided for the analysis of 22 g
and 10-g10 g samples.
6.2 Beakers, 100, 250,100 mL, 250 mL, and 600-mL,600 mL, inverted-rim type.
The sole source of supply of the beakers known to the committee at this time is Kontes Glass Co., Vineland, NJ; order “Anti-Creep” beakers and refer to Drawing No.
9413-A. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at
a meeting of the responsible technical committee , which you may attend.
D2549 − 02 (2017)
6.3 Steam Bath.
6.4 Electric Vibrator, for packing column.
6.5 Weighing Bottles or Erlenmeyer Flasks, 2525 mL and 50 mL.50 mL.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in this test. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
7.2 Bauxite, 2020 mesh to 60-mesh.60 mesh. Before use, activate the bauxite by heating at 538°C (1000°F) for 16 h. 538 °C
(1000 °F) for 16 h. Transfer the activated material to an airtight container while still hot and protect thereafter from atmospheric
moisture.
7.3 Chloroform. (Warning—Toxic. May be fatal if swallowed.)
7.4 Cleaning Solution—Chromic-sulfuric acid.(acid. (Warning— Causes severe burns. A recognized carcinogen, strong
oxidizer, contact with organic material may cause fire.)
7.5 Diethyl Ether, anhydrous. (Warning—Extremely flammable.) The ethyl ether used in this test method should be free of
peroxides as determined by the procedure in “Reagent Chemical, American Chemical Society Specifications.”
7.6 Ethyl Alcohol, denatured, conforming to Formula 2B of the U.S. Bureau of Internal Revenue. (Warning—Flammable.)
7.7 Pressuring Gas, dry air or nitrogen, delivered to the top of the column at a regulated gage pressure of 0 to 2 psi (13.8 kPa).
0 psi to 2 psi (13.8 kPa). (Warning—Compressed gas.)
7.8 n-Pentane, commercial grade, aromatic-free. Some samples of waxy stocks may not dissolve completely in n-pentane, in
which case cyclohexane, commercial grade, aromatic-free, may be substituted for n-pentane. (Warning—Extremely flammable
liquid.)
7.9 Silica Gel, 100100 mesh to 200-mesh.200 mesh.
8. Procedure
NOTE 3—The procedural details differ depending on the initial boiling point of the sample. If the 5 % point is above 178°C (350°F),178 °C (350 °F),
but below 232°C (450°F),232 °C (450 °F), use procedure described in Appendix X1. If above 232°C,232 °C, continue as written depending on amount
of sample to be analyzed. Instructions specific for 2-g2 g samples are given in 8.4.1 – 8.4.13, and instructions specific for 10-g10 g samples are given
in 8.5.1 and 8.5.8.
8.1 Select the appropriate column, depending on whether 22 g or 10 g 10 g of sample are to be analyzed. Clean the column with
chromic-sulfuric acid (Warning—Causes severe burns), followed by distilled or demineralized water, acetone, and dry air or
nitrogen.
8.2 Introduce a small plug of glass wool into the column, pressing it firmly into the lower end to prevent the flow of silica gel
from the column.
8.3 Clamp the column in a vertical position. Add small increments of silica gel, while vibrating the column along its length,
until the tightly packed silica gel extends to the lower mark on the chromatographic column. Continue to vibrate the column and
add bauxite until the bauxite layer extends to the upper mark on the chromatographic column. Vibrate the column for an additional
3 min 3 min after filling is completed.
8.4 If 2 g 2 g of sample are to be analyzed, continue as in 8.4.1, otherwise continue as in 8.5.
8.4.1 If the sample is viscous, warm it with intermittent mixing or shaking until it is completely fluid. Transfer a representative
sample (approximately 2 g) 2 g) to a 25-mL25 mL weighing bottle or flask. Determine the weightmass of the sample to the nearest
1 mg 1 mg by weighing the flask before and after sample transfer. Add 10 mL 10 mL of n-pentane (Warning—Extremely
flammable liquid), to the flask and dissolve the sample. If the sample does not dissolve completely in cold n-pentane, warm it in
warm water or over a steam bath. If the sample does not dissolve in warm n-pentane, take a fresh sample and substitute
cyclohexane for the n-pentane.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed by
the American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
The sole source of supply of the bauxite known to the committee at this time is Porocel Corp., Little Rock, AR. If you are aware of alternative suppliers, please provide
this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee , which you may
attend.
The sole source of supply of the silica gel known to the committee at this time is W.R. Grace and Co., Davison Chemical Div., Baltimore, MD 21203, by specifying
Code 923. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration
at a meeting of the responsible technical committee , which you may attend.
D2549 − 02 (2017)
8.4.2 Add 10 mL 10 mL of n-pentane to the top of the column to prewet the adsorbent. When the liquid level reaches the top
of the bauxite bed, transfer the sample solution from the weighing flask to the top of the column. Rinse the flask with three
successive 3-mL3 mL washes of n-pentane. Add each wash to the top of the column. Then rinse the walls of the column bulb with
two 3-mL3 mL portions of n-pentane, allowing the liquid level to reach the top of the bauxite bed before adding the next portion.
Finally add 35 mL 35 mL of n-pentane to the column bulb.
8.4.3 Place a 50-mL50 mL graduate beneath the column to collect the eluate. The elution rate should be approximately 1
1 mL mL/min.⁄min.
NOTE 4—Gas pressure (Warning—Compressed gas) can be applied to the top of the column as necessary to maintain the elution rate at approximately
11 mL mL/min. ⁄min. If the correct pressure setting is known from previous runs, gas pressure may be applied after addition of the last increment of
n-pentane. Otherwise, gas pressure should be applied when n-pentane begins to elute from the column and should be adjusted to give a flow rate of
approximately 1 1 mL mL/min.⁄min.
8.4.4 When the n-pentane level reaches the top of the bauxite bed, add 80 mL 80 mL of diethyl ether (Warning—Extremely
flammable). Connect the pressuring gas to the top of the column and adjust the pressure to maintain an elution rate of 11 mL ⁄min
to 2 2 mL mL/min.⁄min.
8.4.5 Collect 50 mL 50 mL of n-pentane eluate in the graduate. Rinse the tip of the column with 11 mL to 2 mL 2 mL of
n-pentane, adding this to the 50 mL 50 mL in the graduate (Note 5). Label the 50-mL50 mL graduate as n-pentane eluate.
NOTE 5—The n-pentane will have reached the adsorbent bed before the required volume of eluate has been collected in the 50-mL50 mL receiver.
Continue collection in this receiver after the addition of ether until the proper volume has been collected before changing to the 100-mL100 mL graduate.
8.4.6 When the ether level reaches the top of the bauxite bed, release the gas pressure and add 100 mL 100 mL of chloroform
(Warning—Toxic. May be fatal if swallowed) to the top of the column. Reconnect the gas pressuring system and continue the
elution. When 80 mL 80 mL of eluate have been collected in the graduate, rinse the column tip with 1 mL 1 mL of ether and add
the rinse to the 100-mL100 mL graduate. Change the receiver to a 250-mL250 mL graduate. Label the 100-mL100 mL graduate
as ether-eluted fraction.
8.4.7 When the chloroform level reaches the top of the bauxite bed, release the gas pressure and add 75 mL 75 mL of ethyl
alcohol (Warning—Flammable liquid). Reconnect the gas pressuring system and continue the elution until the alcohol level
reaches the top of the bauxite bed. Release the gas pressure. Rinse the column tip with 1 mL 1 mL of chloroform adding this to
the graduate. Label the 250-mL250 mL graduate as chloroform-alcohol-eluted fraction.
8.4.8 Weigh a 100-mL100 mL inverted-rim beaker to the nearest 1 mg. 1 mg. Quantitatively transfer the n-pentane eluate to this
beaker and allow the n-pentane to evaporate at room temperature. Cyclohexane, if used as the elution solvent, is evaporated on
a steam bath. Evaporation is accelerated in both cases by directing a controlled stream of dry nitrogen downward onto the surface
of the liquid.
8.4.9 When all the solvent appear
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.