ASTM D6729-04(2009)
(Test Method)Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary High Resolution Gas Chromatography
Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary High Resolution Gas Chromatography
SIGNIFICANCE AND USE
Knowledge of the specified individual component composition (speciation) of gasoline fuels and blending stocks is useful for refinery quality control and product specification. Process control and product specification compliance for many individual hydrocarbons may be determined through the use of this test method.
SCOPE
1.1 This test method covers the determination of individual hydrocarbon components of spark-ignition engine fuels and their mixtures containing oxygenate blends (MTBE, ETBE, ethanol, and so forth) with boiling ranges up to 225°C. Other light liquid hydrocarbon mixtures typically encountered in petroleum refining operations, such as blending stocks (naphthas, reformates, alkylates, and so forth) may also be analyzed; however, statistical data was obtained only with blended spark-ignition engine fuels.
1.2 Based on the cooperative study results, individual component concentrations and precision are determined in the range of 0.01 to approximately 30 mass %. The procedure may be applicable to higher and lower concentrations for the individual components; however, the user must verify the accuracy if the procedure is used for components with concentrations outside the specified ranges.
1.3 The test method also determines methanol, ethanol, t-butanol, methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE), t-amyl methyl ether (TAME) in spark ignition engine fuels in the concentration range of 1 to 30 mass %. However, the cooperative study data provided sufficient statistical data for MTBE only.
1.4 Although a majority of the individual hydrocarbons present are determined, some co-elution of compounds is encountered. If this test method is utilized to estimate bulk hydrocarbon group-type composition (PONA) the user of such data should be cautioned that some error will be encountered due to co-elution and a lack of identification of all components present. Samples containing significant amounts of olefinic or naphthenic (for example, virgin naphthas), or both, constituents above n-octane may reflect significant errors in PONA type groupings. Based on the gasoline samples in the interlaboratory cooperative study, this procedure is applicable to samples containing less than 25 mass % of olefins. However, some interfering coelution with the olefins above C7 is possible, particularly if blending components or their higher boiling cuts such as those derived from fluid catalytic cracking (FCC) are analyzed, and the total olefin content may not be accurate.
1.4.1 Total olefins in the samples may be obtained or confirmed, or both, if necessary, by Test Method D 1319 (volume %) or other test methods, such as those based on multidimensional PONA type of instruments.
1.5 If water is or is suspected of being present, its concentration may be determined, if desired, by the use of Test Method D 1744, or equivalent. Other compounds containing oxygen, sulfur, nitrogen, and so forth, may also be present, and may co-elute with the hydrocarbons. If determination of these specific compounds is required, it is recommended that test methods for these specific materials be used, such as Test Methods D 4815 and D 5599 for oxygenates, and D 5623 for sulfur compounds, or equivalent.
1.6 Annex A1 of this test method compares results of the test procedure with other test methods for selected components, including olefins, and several group types for several interlaboratory cooperative study samples. Although benzene, toluene, and several oxygenates are determined, when doubtful as to the analytical results of these components, confirmatory analyses can be obtained by using specific test methods.
1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.
1.8 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 sta...
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Designation: D6729 − 04(Reapproved 2009)
Standard Test Method for
Determination of Individual Components in Spark Ignition
Engine Fuels by 100 Metre Capillary High Resolution Gas
Chromatography
This standard is issued under the fixed designation D6729; 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 naphthenic (for example, virgin naphthas), or both, constitu-
ents above n-octane may reflect significant errors in PONA
1.1 This test method covers the determination of individual
type groupings. Based on the gasoline samples in the inter-
hydrocarbon components of spark-ignition engine fuels and
laboratory cooperative study, this procedure is applicable to
their mixtures containing oxygenate blends (MTBE, ETBE,
samples containing less than 25 mass % of olefins. However,
ethanol, and so forth) with boiling ranges up to 225°C. Other
some interfering coelution with the olefins above C is
light liquid hydrocarbon mixtures typically encountered in
possible, particularly if blending components or their higher
petroleum refining operations, such as blending stocks
boiling cuts such as those derived from fluid catalytic cracking
(naphthas, reformates, alkylates, and so forth) may also be
(FCC) are analyzed, and the total olefin content may not be
analyzed; however, statistical data was obtained only with
accurate.
blended spark-ignition engine fuels.
1.4.1 Total olefins in the samples may be obtained or
1.2 Based on the cooperative study results, individual com-
confirmed, or both, if necessary, by Test Method D1319
ponent concentrations and precision are determined in the
(volume %) or other test methods, such as those based on
range of 0.01 to approximately 30 mass %.The procedure may
multidimensional PONA type of instruments.
be applicable to higher and lower concentrations for the
1.5 If water is or is suspected of being present, its concen-
individual components; however, the user must verify the
tration may be determined, if desired, by the use of Test
accuracy if the procedure is used for components with concen-
Method D1744, or equivalent. Other compounds containing
trations outside the specified ranges.
oxygen, sulfur, nitrogen, and so forth, may also be present, and
1.3 The test method also determines methanol, ethanol,
may co-elute with the hydrocarbons. If determination of these
t-butanol, methyl t-butyl ether (MTBE), ethyl t-butyl ether
specific compounds is required, it is recommended that test
(ETBE), t-amyl methyl ether (TAME) in spark ignition engine
methods for these specific materials be used, such as Test
fuels in the concentration range of 1 to 30 mass %. However,
Methods D4815 and D5599 for oxygenates, and D5623 for
the cooperative study data provided sufficient statistical data
sulfur compounds, or equivalent.
for MTBE only.
1.6 Annex A1 of this test method compares results of the
1.4 Although a majority of the individual hydrocarbons
test procedure with other test methods for selected
present are determined, some co-elution of compounds is
components, including olefins, and several group types for
encountered. If this test method is utilized to estimate bulk
several interlaboratory cooperative study samples. Although
hydrocarbon group-type composition (PONA) the user of such
benzene,toluene,andseveraloxygenatesaredetermined,when
data should be cautioned that some error will be encountered
doubtful as to the analytical results of these components,
due to co-elution and a lack of identification of all components
confirmatory analyses can be obtained by using specific test
present. Samples containing significant amounts of olefinic or
methods.
1.7 The values stated in SI units are to be regarded as the
This test method is under the jurisdiction of ASTM Committee D02 on
standard. The values given in parentheses are provided for
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.04.0L on Gas Chromatography Methods. information purposes only.
Current edition approved April 15, 2009. Published July 2009. Originally
´1 1.8 This standard does not purport to address all of the
approved in 2001. Last previous edition approved in 2004 as D6729–04 . DOI:
safety concerns, if any, associated with its use. It is the
10.1520/D6729-04R09.
*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
D6729 − 04 (2009)
responsibility of the user of this standard to establish appro- 6. Apparatus
priate safety and health practices and determine the applica-
6.1 Gas Chromatograph, a gas chromatograph equipped
bility of regulatory limitations prior to use.
with cryogenic column oven cooling and capable of producing
repeatable oven ramps from 0° to at least 300°C is required.
2. Referenced Documents
The following features are useful during the sample analysis
2.1 ASTM Standards:
phase: electronic flow readout, electronic sample split-ratio
D1319 Test Method for Hydrocarbon Types in Liquid Petro-
readout,andelectronicpneumaticcontrolofflow.Thoughtheir
leum Products by Fluorescent Indicator Adsorption
use is not required, careful review of this test method will
D1744 Test Method for Determination of Water in Liquid
demonstrate the usefulness of a gas chromatograph equipped
Petroleum Products by Karl Fischer Reagent (Withdrawn
with these features. These features will replace the need to
2000)
carry out the manual calculations that must be performed as
D4815 Test Method for Determination of MTBE, ETBE,
listed in 8.1 and 8.2.
TAME, DIPE, tertiary-Amyl Alcohol and C to C Alco-
1 4
6.2 Inlet—a capillary split/splitless inlet system operated in
hols in Gasoline by Gas Chromatography
thesplitmodeisrecommended.Itmustbeoperatedinitslinear
D5599 Test Method for Determination of Oxygenates in
range. Refer to 8.4 to determine the proper split ratio.
Gasoline by Gas Chromatography and Oxygen Selective
6.2.1 CarrierGasPneumaticControl—Constantcarriergas
Flame Ionization Detection
pressurecontrolwasusedbyallcooperativestudyparticipants.
D5623 Test Method for Sulfur Compounds in Light Petro-
This may be either direct pressure to the inlet (injector) or by
leum Liquids by Gas Chromatography and Sulfur Selec-
using a total flow/back pressure system.
tive Detection
6.2.2 Pneumatic Operation of the Chromatograph—Theuse
E355 Practice for Gas ChromatographyTerms and Relation-
of constant pressure was the mode of operating the gas
ships
chromatography used by the participants in the interlaboratory
cooperative study. Other carrier gas control methods such as
3. Terminology
constant flow (pressure programming) may be used, but this
3.1 Definitions—This test method makes reference to many
may change the chromatography elution pattern unless the
common gas chromatographic procedures, terms, and relation-
temperature programming profile is also adjusted to compen-
ships. Detailed definitions can be found in Practice E355.
sate for the flow differences.
6.2.3 Temperature Control—The injector operated in the
4. Summary of Test Method
split mode shall be heated by a separate heating zone and
4.1 Representative samples of the petroleum liquid are
heated to temperatures of 200 to 275°C.
introduced into a gas chromatograph equipped with an open
6.3 Column,afusedsilicacapillarycolumn,100minlength
tubular (capillary) column coated with the specified stationary
by 0.25 mm inside diameter, coated with a 0.5 µm film of
phase. Helium carrier gas transports the vaporized sample
bonded dimethylpolysiloxane. The column must meet the
through the column, in which it is partitioned into individual
resolution requirements expressed in 8.3. Columns from two
components which are sensed with a flame ionization detector
different commercial sources were used in the interlaboratory
as they elute from the end of the column. The detector signal
cooperative study.
is recorded digitally by way of an integrator or integrating
computer. Each eluting component is identified by comparing
6.4 Data System, a computer based chromatography data
its retention time to that established by analyzing reference
system capable of accurately and repeatedly measuring the
standards or samples under identical conditions. The concen-
retention time and areas of eluting peaks. The system shall be
tration of each component in mass % is determined by
abletoacquiredataatarateofatleast10Hz.Althoughitisnot
normalization of the peak areas after correction of selected
mandatory, a data system which calculates column resolution
components with detector response factors. The unknown
(R) is extremely useful as it will replace the need to carry out
components are reported individually and as a summary total.
the manual calculations which must be performed as listed in
8.3.
5. Significance and Use
6.4.1 Electronic Integrators, shall be capable of storing up
5.1 Knowledge of the specified individual component com-
to 400 components in the peak table and shall be able to
position (speciation) of gasoline fuels and blending stocks is
acquire the data at 10 Hz or faster speeds. They shall be
useful for refinery quality control and product specification.
capable of integrating peaks having peak widths at half height
Process control and product specification compliance for many
which are 1.0s wide. The integrator must be capable of
individual hydrocarbons may be determined through the use of
displaying the integration mode of partially resolved peaks. In
this test method.
addition, these integrators should be able to download a
commonly readable format of data (that is, ASCII) to a
computer in order to facilitate data processing.
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
6.5 Sample Introduction—Sample introduction by way of a
Standards volume information, refer to the standard’s Document Summary page on
valve, automatic injection device, robotic arm or other auto-
the ASTM website.
matic means is highly recommended. An automatic sample
The last approved version of this historical standard is referenced on
www.astm.org. introduction device is essential to the reproducibility of the
D6729 − 04 (2009)
analysis. Manual injections are not recommended. All of the where:
reproducibility data reported by this test method for the
F = flow rate as calculated by using the equation,
samples analyzed were gathered using automatic injection
r = column radius, cm,
devices. L = column length, cm,
P = inlet pressure,
i
6.6 Flame Ionization Detector (FID)— The gas chromato-
P = outlet pressure,
o
graph should possess a FID having a sensitivity of 0.005
P = reference pressure, 1 atm,
ref
coulombs/g for n-butane. The linear dynamic range of the
T = temperature of the column oven,
detector should be 10 or better. The detector is heated to
T = temperature at the column outlet, and
ref
300°C.
µ = linear velocity, cm/s.
7. Reagents and Materials
split vent flow1F
split ratio 5 S 5 (3)
F
7.1 Calibrating Standard Mixture—A spark ignition engine
fuelstandardofknowncompositionandconcentrationbymass
8.2.1 The column flow rate is calculated by the use of Eq 2.
can be used. In order to corroborate the identification of the
Use the results obtained from Eq 3 to adjust the split flow until
sample, a typical chromatogram (Fig. 1) was obtained from
a split flow of approximately 200:1 is achieved.
reference sample ARC96OX.
8.3 Evaluation of Column Performance :
7.2 Gas Chromatograph Gases—All of the following gases
8.3.1 Prior to using the column described in Table 1,
shall have a purity of 99.999 % (V/V) or greater.
measure the resolution of the column under the conditions of
Table 2. Check that the resolution for the following pairs of
NOTE1—Warning:Gasesarecompressed.Someareflammableandall
gases are under high pressure. components is obtained using Eq 4 to calculate the resolution
of a pair of components:
7.2.1 Helium—The test data was developed with helium as
the carrier gas. It is possible that other carrier gases may be
2~t 2 t !
R2 R1
R 5 (4)
usedforthistestmethod.Atthistime,nodataisavailablefrom 1.699 W 1W
~ !
h1 h2
this test method with other carrier gases.
where:
7.2.2 Air, Hydrogen and Make-up Gas (Helium or
R = resolution,
Nitrogen), shall have a purity of 99.999 % (V/V) or greater.
t = retention time of the first member of the pair,
R2
t = retention time of the second member of the pair,
8. Instrument Check Out Prior to Analysis R1
W = peak width at half height of the first member of the
h1
8.1 Setting:
pair, and
8.1.1 Linear Gas Velocity—If the gas chromatograph is
W = peakwidthathalfheightofthesecondmemberofthe
h2
equippedwithanelectronicflowreadoutdevice,settheflowto
pair.
1.8 mL/min. This is achieved by setting the carrier gas flow
8.3.1.1 Column resolution should be checked frequently by
rate by injection of methane or natural gas at 35°C. Ensure that
examining the resolution of these compounds.
the retention time is 7.00 6 0.05 min. This corresponds to a
8.3.2 Evaluation of the Baseline—Carry out a blank base-
linear velocity of 25 to 26 cm/s. This is equivalent to retention
line run utilizing no solvent injection, by setting the GC in
times of methane at 0°C ranging from 6.5 to 6.8 min.
accordance with the conditions of Table 1.
8.1.2 If the gas chromatograph is not equipped with an
8.3.3 Subtract the baseline from a sample chromatogram
electronic flow readout device, calculate the linear gas velocity
and verify that the residual signal at the beginning of the
in cm/s using Eq 1.
chromatogram does not differ from the end of the chromato-
column length cm
~ !
gram by more than 2 %.
linear gas velocity 5 V 5 (1)
retention time of methane~s!
8.4 Evaluation of Splitter Linearity— Using the reference
8.1.3 The typical retention times for methane and linear gas
gasoline sample, inject this sample according to the schedule
velocity for helium are 6.5 to 6.8 and 24 to 26 cm/s,
listed in Table 3.
respectively.
8.4.1 Select from the chromatogram about 10 to 15
components, which have concentrations in the range of .01 to
8.2 Setting the Split Ratio—If the gas chromatograph is
30 weight %.Tabulate for each split ratio the concentrations of
equipped with an electronic split-ratio readout device, set the
the 10 to 15 components. Verify that for each component
split ratio to a sample split of 200:1. If the gas chromatograph
selected, its concentration does not vary by more than 3 %.
i
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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.
An American National Standard
Designation:D6729–01 Designation: D 6729 – 04 (Reapproved 2009)
Standard Test Method for
Determination of Individual Components in Spark Ignition
Engine Fuels by 100 MeterMetre Capillary High Resolution
Gas Chromatography
This standard is issued under the fixed designation D 6729; 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 determination of individual hydrocarbon components of spark-ignition engine fuels and their
mixtures containing oxygenate blends (MTBE, ETBE, ethanol, and so forth) with boiling ranges up to 225°C. Other light liquid
hydrocarbon mixtures typically encountered in petroleum refining operations, such as blending stocks (naphthas, reformates,
alkylates, and so forth) may also be analyzed; however, statistical data was obtained only with blended spark-ignition engine fuels.
1.2 Based on the cooperative study results, individual component concentrations and precision are determined in the range of
0.01 to approximately 30 mass %. The procedure may be applicable to higher and lower concentrations for the individual
components; however, the user must verify the accuracy if the procedure is used for components with concentrations outside the
specified ranges.
1.3 The test method also determines methanol, ethanol, t-butanol, methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE),
t-amyl methyl ether (TAME) in spark ignition engine fuels in the concentration range of 1 to 30 mass %. However, the cooperative
study data provided sufficient statistical data for MTBE only.
1.4 Although a majority of the individual hydrocarbons present are determined, some co-elution of compounds is encountered.
If this test method is utilized to estimate bulk hydrocarbon group-type composition (PONA) the user of such data should be
cautioned that some error will be encountered due to co-elution and a lack of identification of all components present. Samples
containing significant amounts of olefinic or naphthenic (for example, virgin naphthas), or both, constituents above n-octane may
reflect significant errors in PONA type groupings. Based on the gasoline samples in the interlaboratory cooperative study, this
procedure is applicable to samples containing less than 25 mass % of olefins. However, some interfering coelution with the olefins
above C is possible, particularly if blending components or their higher boiling cuts such as those derived from fluid catalytic
cracking (FCC) are analyzed, and the total olefin content may not be accurate.
1.4.1 Total olefins in the samples may be obtained or confirmed, or both, if necessary, by Test Method D 1319 (volume %) or
other test methods, such as those based on multidimensional PONA type of instruments.
1.5 If water is or is suspected of being present, its concentration may be determined, if desired, by the use of Test Method
D 1744, or equivalent. Other compounds containing oxygen, sulfur, nitrogen, and so forth, may also be present, and may co-elute
with the hydrocarbons. If determination of these specific compounds is required, it is recommended that test methods for these
specific materials be used, such as Test Methods D 4815 and D 5599 for oxygenates, and D 5623 for sulfur compounds, or
equivalent.
1.6 Annex A1 of this test method compares results of the test procedure with other test methods for selected components,
including olefins, and several group types for several interlaboratory cooperative study samples. Although benzene, toluene, and
several oxygenates are determined, when doubtful as to the analytical results of these components, confirmatory analyses can be
obtained by using specific test methods.
1.7 ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareprovidedforinformation
purposes only.
1.8 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.
This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.04.0L
on Gas Chromatographic Methods.
Current edition approved Nov. 10, 2001. Published January 2002.on Gas Chromatography Methods.
´1
Current edition approved April 15, 2009. Published July 2009. Originally approved in 2001. Last previous edition approved in 2004 as D 6729–04 .
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6729 – 04 (2009)
2. Referenced Documents
2.1 ASTM Standards:
D 1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption
D 1744 Standard Test Method for Determination of Water in Liquid Petroleum Products by Karl Fischer Reagent
D 4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, t-Amyltertiary-Amyl Alcohol and C to C Alcohols
1 4
in Gasoline by Gas Chromatography
D 5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame
Ionization Detection
D 5623 TestMethodforSulfurCompoundsinLightPetroleumLiquidsbyGasChromatographyandSulfurSelectiveDetection
E 355 Practice for Gas Chromatography Terms and Relationships
3. Terminology
3.1 Definitions—Thistestmethodmakesreferencetomanycommongaschromatographicprocedures,terms,andrelationships.
Detailed definitions can be found in Practice E 355.
4. Summary of Test Method
4.1 Representative samples of the petroleum liquid are introduced into a gas chromatograph equipped with an open tubular
(capillary) column coated with the specified stationary phase. Helium carrier gas transports the vaporized sample through the
column, in which it is partitioned into individual components which are sensed with a flame ionization detector as they elute from
the end of the column. The detector signal is recorded digitally by way of an integrator or integrating computer. Each eluting
component is identified by comparing its retention time to that established by analyzing reference standards or samples under
identical conditions. The concentration of each component in mass % is determined by normalization of the peak areas after
correction of selected components with detector response factors. The unknown components are reported individually and as a
summary total.
5. Significance and Use
5.1 Knowledge of the specified individual component composition (speciation) of gasoline fuels and blending stocks is useful
for refinery quality control and product specification. Process control and product specification compliance for many individual
hydrocarbons may be determined through the use of this test method.
6. Apparatus
6.1 Gas Chromatograph, a gas chromatograph equipped with cryogenic column oven cooling and capable of producing
repeatable oven ramps from 0° to at least 300°C is required. The following features are useful during the sample analysis phase:
electronic flow readout, electronic sample split-ratio readout, and electronic pneumatic control of flow. Though their use is not
required, careful review of this test method will demonstrate the usefulness of a gas chromatograph equipped with these features.
These features will replace the need to carry out the manual calculations that must be performed as listed in 8.1 and 8.2.
6.2 Inlet—a capillary split/splitless inlet system operated in the split mode is recommended. It must be operated in its linear
range. Refer to 8.4 to determine the proper split ratio.
6.2.1 Carrier Gas Pneumatic Control— Constant carrier gas pressure control was used by all cooperative study participants.
This may be either direct pressure to the inlet (injector) or by using a total flow/back pressure system.
6.2.2 Pneumatic Operation of the Chromatograph—The use of constant pressure was the mode of operating the gas
chromatography used by the participants in the interlaboratory cooperative study. Other carrier gas control methods such as
constantflow(pressureprogramming)maybeused,butthismaychangethechromatographyelutionpatternunlessthetemperature
programming profile is also adjusted to compensate for the flow differences.
6.2.3 Temperature Control—The injector operated in the split mode shall be heated by a separate heating zone and heated to
temperatures of 200 to 275°C.
6.3 Column, a fused silica capillary column, 100 m in length by 0.25 mm inside diameter, coated with a 0.5 mmµm film of
bonded dimethylpolysiloxane. The column must meet the resolution requirements expressed in 8.3. Columns from two different
commercial sources were used in the interlaboratory cooperative study.
6.4 Data System, a computer based chromatography data system capable of accurately and repeatedly measuring the retention
time and areas of eluting peaks. The system shall be able to acquire data at a rate of at least 10 Hz.Although it is not mandatory,
a data system which calculates column resolution (R) is extremely useful as it will replace the need to carry out the manual
calculations which must be performed as listed in 8.3.
Annual Book of ASTM Standards, Vol 05.01.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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.
Discontinued; see 1999 Annual Book of ASTM Standards, Vol 05.01.
Withdrawn. The last approved version of this historical standard is referenced on www.astm.org.
D 6729 – 04 (2009)
6.4.1 Electronic Integrators, shall be capable of storing up to 400 components in the peak table and shall be able to acquire the
data at 10 Hz or faster speeds. They shall be capable of integrating peaks having peak widths at half height which are 1.0s wide.
The integrator must be capable of displaying the integration mode of partially resolved peaks. In addition, these integrators should
be able to download a commonly readable format of data (that is, ASCII) to a computer in order to facilitate data processing.
6.5 Sample Introduction—Sample introduction by way of a valve, automatic injection device, robotic arm or other automatic
means is highly recommended.An automatic sample introduction device is essential to the reproducibility of the analysis. Manual
injectionsarenotrecommended.Allofthereproducibilitydatareportedbythistestmethodforthesamplesanalyzedweregathered
using automatic injection devices.
6.6 Flame Ionization Detector (FID)— The gas chromatograph should possess a FID having a sensitivity of 0.005 coulombs/g
for n-butane. The linear dynamic range of the detector should be 10 or better. The detector is heated to 300°C.
7. Reagents and Materials
7.1 Calibrating Standard Mixture—Aspark ignition engine fuel standard of known composition and concentration by mass can
be used. In order to corroborate the identification of the sample, a typical chromatogram (Fig. 1) was obtained from reference
sample ARC96OX.
7.2 Gas Chromatograph Gases—All of the following gases shall have a purity of 99.999 % (V/V) or greater.
NOTE 1—Warning: Gases are compressed. Some are flammable and all gases are under high pressure.
7.2.1 Helium—The test data was developed with helium as the carrier gas. It is possible that other carrier gases may be used
for this test method. At this time, no data is available from this test method with other carrier gases.
7.2.2 Air, Hydrogen and Make-up Gas (Helium or Nitrogen), shall have a purity of 99.999 % (V/V) or greater.
8. Instrument Check Out Prior to Analysis
8.1 Setting:
8.1.1 Linear Gas Velocity—If the gas chromatograph is equipped with an electronic flow readout device, set the flow to 1.8
mL/min. This is achieved by setting the carrier gas flow rate by injection of methane or natural gas at 35°C. Ensure that the
retention time is 7.00 6 0.05 min. This corresponds to a linear velocity of 25 to 26 cm/s. This is equivalent to retention times of
methane at 0°C ranging from 6.5 to 6.8 min.
8.1.2 If the gas chromatograph is not equipped with an electronic flow readout device, calculate the linear gas velocity in cm/s
using Eq 1.
column length ~cm!
linear gas velocity 5 V 5 (1)
retention time of methane~s!
8.1.3 The typical retention times for methane and linear gas velocity for helium are 6.5 to 6.8 and 24 to 26 cm/s, respectively.
8.2 Setting the Split Ratio—If the gas chromatograph is equipped with an electronic split-ratio readout device, set the split ratio
to a sample split of 200:1. If the gas chromatograph is not equipped with an electronic split-ratio readout device, one must first
calculate column flow rate and then proceed to calculating split ratio using Eq 2 and 3.
60 p r ! L T !2 P – P !
~ ~ ~
ref i o
column flow rate 5 F 5 (2)
2 2
~T!3~P !~P – P !µ
ref i o
where:
F = flow rate as calculated by using the equation,
r = column radius, cm,
L = column length, cm,
P = inlet pressure,
i
P = outlet pressure,
o
P = reference pressure, 1 atm,
ref
T = temperature of the column oven,
T = temperature at the column outlet, and
ref
µ = linear velocity, cm/s.
split vent flow 1 F
split ratio 5 S 5 (3)
F
8.2.1 The column flow rate is calculated by the use of Eq 2. Use the results obtained from Eq 3 to adjust the split flow until
a split flow of approximately 200:1 is achieved.
8.3 Evaluation of Column Performance :
8.3.1 Prior to using the column described in Table 1, measure the resolution of the column under the conditions of Table 2.
Annual Book of ASTM Standards, Vol 05.03.
Reference spark ignition sample No.ARC 960X obtained from theAlberta Research Council, Edmonton,Alberta, Canada. Other samples are available from suppliers.
D 6729 – 04 (2009)
FIG. 1 Chromatogram for Reference Spiked Gasoline
D 6729 – 04 (2009)
FIG. 1 Chromatogram for Reference Spiked Gasoline (continued)
Check that the resolution for the following pairs of components is obtained using Eq 4 to calculate the resolution of a pair of
components:
~t – t
...
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