ASTM D6733-01(2020)
(Test Method)Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 50-Metre Capillary High Resolution Gas Chromatography
Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 50-Metre Capillary High Resolution Gas Chromatography
SIGNIFICANCE AND USE
5.1 Knowledge of the 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 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. The tables in Annex A1 enumerate the components reported. Component concentrations are determined in the range from 0.10 % to 15 % by mass. The procedure may be applicable to higher and lower concentrations for the individual components; however, the user must verify the accuracy if the procedures are used for components with concentrations outside the specified ranges.
1.2 This test method is applicable also to spark-ignition engine fuel blends containing oxygenated components. However, in this case, the oxygenate content must be determined by Test Methods D5599 or D4815.
1.3 Benzene co-elutes with 1-methylcyclopentene. Benzene content must be determined by Test Method D3606 or D5580.
1.4 Toluene co-elutes with 2,3,3-trimethylpentane. Toluene content must be determined by Test Method D3606 or D5580.
1.5 Although a majority of the individual hydrocarbons present are determined, some co-elution of compounds is encountered. If this procedure is utilized to estimate bulk hydrocarbon group-type composition (PONA) the user of such data should be cautioned that error may be encountered due to co-elution and a lack of identification of all components present. Samples containing significant amounts of naphthenic (for example, virgin naphthas) constituents above n-octane may reflect significant errors in PONA type groupings. Based on the interlaboratory cooperative study, this procedure is applicable to samples having concentrations of olefins less than 20 % by mass. However, significant 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. Many of the olefins in spark ignition fuels are at a concentration below 0.10 %; they are not reported by this test method and may bias the total olefin results low.
1.5.1 Total olefins in the samples may be obtained or confirmed, or both, by Test Method D1319 (volume %) or other test methods, such as those based on multidimensional PONA type of instruments.
1.6 If water is or is suspected of being present, its concentration may be determined, if desired, by the use of Test Method D1744. Other compounds containing 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 Method D5623 for sulfur compounds.
1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 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...
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Standards Content (Sample)
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.
Designation: D6733 − 01 (Reapproved 2020)
Standard Test Method for
Determination of Individual Components in Spark Ignition
Engine Fuels by 50-Metre Capillary High Resolution Gas
Chromatography
This standard is issued under the fixed designation D6733; 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 may reflect significant errors in PONA type groupings. Based
on the interlaboratory cooperative study, this procedure is
1.1 This test method covers the determination of individual
applicabletosampleshavingconcentrationsofolefinslessthan
hydrocarbon components of spark-ignition engine fuels with
20 % by mass. However, significant interfering coelution with
boiling ranges up to 225 °C. Other light liquid hydrocarbon
the olefins above C is possible, particularly if blending
mixtures typically encountered in petroleum refining
components or their higher boiling cuts such as those derived
operations, such as, blending stocks (naphthas, reformates,
from fluid catalytic cracking (FCC) are analyzed, and the total
alkylates, and so forth) may also be analyzed; however,
olefincontentmaynotbeaccurate.Manyoftheolefinsinspark
statistical data was obtained only with blended spark-ignition
ignition fuels are at a concentration below 0.10 %; they are not
engine fuels. The tables in Annex A1 enumerate the compo-
reported by this test method and may bias the total olefin
nents reported. Component concentrations are determined in
results low.
the range from 0.10 % to 15 % by mass.The procedure may be
1.5.1 Total olefins in the samples may be obtained or
applicabletohigherandlowerconcentrationsfortheindividual
confirmed, or both, by Test Method D1319 (volume %) or
components; however, the user must verify the accuracy if the
other test methods, such as those based on multidimensional
procedures are used for components with concentrations out-
PONA type of instruments.
side the specified ranges.
1.2 This test method is applicable also to spark-ignition
1.6 If water is or is suspected of being present, its concen-
engine fuel blends containing oxygenated components.
tration may be determined, if desired, by the use of Test
However, in this case, the oxygenate content must be deter-
Method D1744. Other compounds containing sulfur, nitrogen,
mined by Test Methods D5599 or D4815.
and so forth, may also be present, and may co-elute with the
hydrocarbons. If determination of these specific compounds is
1.3 Benzene co-elutes with 1-methylcyclopentene. Benzene
required, it is recommended that test methods for these specific
content must be determined by Test Method D3606 or D5580.
materials be used, such as Test Method D5623 for sulfur
1.4 Toluene co-elutes with 2,3,3-trimethylpentane. Toluene
compounds.
content must be determined by Test Method D3606 or D5580.
1.7 The values stated in SI units are to be regarded as the
1.5 Although a majority of the individual hydrocarbons
standard. The values given in parentheses are provided for
present are determined, some co-elution of compounds is
information only.
encountered. If this procedure is utilized to estimate bulk
hydrocarbon group-type composition (PONA) the user of such
1.8 This standard does not purport to address all of the
data should be cautioned that error may be encountered due to
safety concerns, if any, associated with its use. It is the
co-elution and a lack of identification of all components
responsibility of the user of this standard to establish appro-
present. Samples containing significant amounts of naphthenic
priate safety, health, and environmental practices and deter-
(for example, virgin naphthas) constituents above n-octane
mine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accor-
dance with internationally recognized principles on standard-
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of
ization established in the Decision on Principles for the
Subcommittee D02.04.0L on Gas Chromatography Methods.
Development of International Standards, Guides and Recom-
Current edition approved Nov. 1, 2020. Published November 2020. Originally
mendations issued by the World Trade Organization Technical
approved in 2001. Last previous edition approved in 2016 as D6733 – 01 (2016).
DOI: 10.1520/D6733-01R20. Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6733 − 01 (2020)
2. Referenced Documents 5. Significance and Use
2.1 ASTM Standards: 5.1 Knowledge of the individual component composition
D1319 Test Method for Hydrocarbon Types in Liquid Petro- (speciation) of gasoline fuels and blending stocks is useful for
leum Products by Fluorescent Indicator Adsorption refinery quality control and product specification. Process
D1744 Test Method for Determination of Water in Liquid control and product specification compliance for many indi-
Petroleum Products by Karl Fischer Reagent (Withdrawn vidual hydrocarbons may be determined through the use of this
2016) test method.
D3606 Test Method for Determination of Benzene and
6. Apparatus
Toluene in Spark Ignition Fuels by Gas Chromatography
6.1 Instrumentation—A gas chromatograph capable of op-
D4057 Practice for Manual Sampling of Petroleum and
erating under the conditions outlined in Table 1, equipped with
Petroleum Products
a split injector, a carrier gas pressure control, and a flame
D4420 Test Method for Determination of Aromatics in
ionization detector which are required.
Finished Gasoline by Gas Chromatography (Withdrawn
2004)
6.2 Sample Introduction System—Manual or automatic liq-
D4815 Test Method for Determination of MTBE, ETBE,
uid syringe sample injection may be employed.
TAME, DIPE, tertiary-Amyl Alcohol and C to C Alco-
1 4
6.3 Data Acquisition System—Any data system can be used
hols in Gasoline by Gas Chromatography
with a requirement:
D5580 Test Method for Determination of Benzene, Toluene,
6.3.1 Sampling rate of 10 Hz or more with a storage of
Ethylbenzene, p/m-Xylene, o-Xylene, C and Heavier
sampling data for later processing.
Aromatics, and Total Aromatics in Finished Gasoline by
6.3.2 Capacity for at least 400 peaks/analysis.
Gas Chromatography
6.3.3 Identification of individual components from retention
D5599 Test Method for Determination of Oxygenates in
time; software can be used to automatically identify the peaks
Gasoline by Gas Chromatography and Oxygen Selective
with the index system determined from Table A1.1 or Table
Flame Ionization Detection
A1.2.
D5623 Test Method for Sulfur Compounds in Light Petro-
leum Liquids by Gas Chromatography and Sulfur Selec- 6.4 Sampling—Two millilitres or more crimp-top vials and
tive Detection aluminum caps with polytetrafluoroethylene (PTFE)-lined
E355 Practice for Gas Chromatography Terms and Relation- septa are used to transfer the sample.
ships
6.5 Capillary Column—A 50 m fused silica capillary col-
umn with an internal diameter of 0.2 mm, containing a 0.5 µm
3. Terminology
film thickness of bonded dimethylpolysiloxane phase is used.
3.1 Definitions—This test method makes reference to many
The features must be respected to reproduce the separation of
common gas chromatographic procedures, terms, and relation-
the reference chromatogram. The column must meet the
ships. Detailed definitions can be found in Practice E355.
criteria of efficiency, resolution, and polarity defined in Section
10.
4. Summary of Test Method
7. Reagents and Materials
4.1 Representative samples of the petroleum liquid are
introduced into a gas chromatograph equipped with an open
7.1 Carrier Gas and Make-up, helium, 99.99 mol % pure.
tubular (capillary) column coated with specified stationary
(Warning—Compressed gas under high pressure.)
phase(s). Helium carrier gas transports the vaporized sample
7.2 Fuel Gas, hydrogen, hydrocarbon free, 99.99 mol %
through the column in which it is partitioned into individual
pure. (Warning—Compressed gas under high pressure. Ex-
components, which are sensed with a flame ionization detector
tremely flammable.)
as they elute from the end of the column. The detector signal
is recorded digitally by way of an integrator or integrating
TABLE 1 Operating Conditions
computer. Each eluting component is identified by comparing
Temperatures Method 1 Method 2
its retention time to those established by analyzing reference
Column initial isotherm, °C 35 10
standards or samples under identical conditions. The concen-
Initial hold time, min. 10 15
Rate 1, °C/min. 1.1 1.3
tration of each component in mass % is determined by normal-
Final temperature 1, °C 114 70
ization of the peak areas after correction of selected compo-
Hold time 2, min. 0 0
nents with detector response factors. The unknown
Rate 2, °C/min 1.7 1.7
Final temperature 2, °C 250 250
components are reported individually as well as a summary
Final hold time 2, min. 5 20
total.
Injector, °C 250 250
Detector, °C 280 280
Carrier gas helium pressure, kPA (psi) 207 (30) 190 (27)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Flow rate (initial isotherm), mL/min. 0.9 0.7
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Average linear velocity, cm/s 22 21.5
Standards volume information, refer to the standard’s Document Summary page on
Injection
the ASTM website.
Sample size, µL 0.5 0.3
The last approved version of this historical standard is referenced on Splitter vent–flow out, mL/min. 250 200
www.astm.org.
D6733 − 01 (2020)
TABLE 2 Reference Retention Times of Normal Paraffins
7.3 Oxidizing Gas, air, 99 mol %. (Warning—Compressed
gas under high pressure.)
NOTE 1—Minutes and tenths of a minute.
Method Method Method Method Method Method
7.4 n-Pentane, 99+ mol % pure. (Warning—Extremely
1 1 1 2 2 2
flammable. Harmful if inhaled.)
n-Paraffins Lower Refer- Upper Lower Refer- Upper
Time ence Time Time ence Time
7.5 n-Hexane, 99+ % mol % pure. (Warning—Extremely
Time Time
flammable. Harmful if inhaled.)
n-Heptane 18.5 19.4 20.3 39.5 40.7 42.0
n-Octane 32.0 33.0 34.0 57.0 57.8 59.0
7.6 n-Heptane, 99+ mol % pure. (Warning—Extremely
n-Dodecane 92.8 94.0 95.2 106.4 107.6 108.8
flammable. Harmful if inhaled.)
7.7 2-Methylheptane, 99+ mol % pure. (Warning—
Extremely flammable. Harmful if inhaled.)
7.8 4-Methylheptane, 99+ mol % pure. (Warning—
Initial temperature 35 °C
Extremely flammable. Harmful if inhaled.)
Hold time 50 min
Final temperature 220 °C
7.9 n-Octane, 99+ mol % pure. (Warning—Extremely
Hold time 20 min
Rate 3 °C ⁄min.
flammable. Harmful if inhaled.)
10.2 Column Evaluation—To perform the required
7.10 n-Dodecane, 99+ mol % pure. (Warning—Extremely
separation, the column must meet three criteria of separation:
flammable. Harmful if inhaled.)
efficiency, resolution, and polarity.
7.11 Toluene, 99+ mol % pure. (Warning—Extremely 10.2.1 Effıciency—The number of theoretical plates is cal-
flammable. Harmful if inhaled.)
culated with the normal octane peak using Eq 1:
n 5 5.545 Rt/W (1)
~ !
7.12 System Performance Mixture—Weigh an equal amount 0.5
of n-pentane, n-heptane, n-octane, n-dodecane,
where:
2-methylheptane, 4-methylheptane, and toluene. Dilute this
n = number of theoretical plates,
mixture in n-hexane to obtain a concentration of 2 % by mass
Rt = retention time of normal octane, and
for each compound.
W = mid-height peak width of normal octane in the same
0.5
unit as retention time.
8. Sampling
10.2.1.1 The number of theoretical plates must be greater
8.1 Container Sampling—Samples shall be taken as de-
than 200 000.
scribed in Practice D4057 for instructions on manual sampling
10.2.2 Resolution—Resolution is determined between the
into open container.
peaks of 2-methylheptane and 4-methylheptane using Eq 2:
8.2 The sample and a 2 mLvial must be cooled at 4 °C. Part
2 Rt 2 Rt
~ !
a b
~ ! ~ !
R 5 (2)
ofthesampleistransferredto the vial up to 80 %ofitsvolume,
1.699 W 1W
~ !
0.5~a! 0.5~b!
and aluminum cap with septum is crimped.
where:
Rt = retention time of 4-methylheptane,
9. Preparation of Apparatus
(a)
Rt = retention time of 2-methylheptane,
(b)
9.1 Installation—Install and condition column in accor-
W = mid-height peak width of 4-methylheptane in the
0.5(a)
dance with the supplier’s instruction.
same unit as retention time, and
W = mid-height peak width of 2-methylheptane in the
0.5(b)
9.2 Operating Conditions—Two sets of operating condi-
same unit as retention time.
tions are proposed in Table 1, the first with an initial column
temperature above the ambient temperature, the second with a
10.2.2.1 The resolution must be equal to 4 or greater than
sub-ambient column temperature profile. Adjust the operating
1.20.
conditions of the gas chromatograph to conform to the first or
10.2.3 Polarity—Polarity is defined by the McReynolds
second method.
constant of toluene, using Eq 3:
9.3 Carrier Gas Pressure—Set a correct carrier gas pressure Rn 5 Ki 2 Ki (3)
tol ana squalane
using the system performance mixture such that the retention
where:
time of n-Heptane, n-Octane and n-Dodecane are between the
Ki = toluene Kovats index on Squalane at
squalane
values given in Table 2.
35 °C = 742.6, and
Ki = tolueneKovatsindexontheanalyticalcolumnat
ana
10. System Performance Evaluation
35 °C.
10.1 Evaluation of the column and linearity of the split
10.2.3.1 Toluene Kovats index is calculated using Eq 4:
injection are carried out with a system performance mixture
logT' 2 logT'
R t R h
~ ! ~ !
defined in 7.12 and with the column temperature conditions
Ki 5 7001100 (4)
S D
ana
logT' 2 logT'
defined in the following table. R~o! R~h!
D6733 − 01 (2020)
where: 12.3 Integration of Chromatogram—Integration codes must
be selected to obtain a horizontal baseline with a perpendicular
T' = adjusted retention time for toluene,
R(t)
droptothebaselineforpartiallyresolvedpeaks.Anexampleof
T' = adjusted retention time for n-heptane, and
R(h)
T' = adjusted retention time for n-octane. correct baseline is given in Figs. A1.1 and A1.2.
R(o)
10.2.3.2 Adjusted retention time of a peak is determined by 12.4 Identification—Each peak is identified by matching the
subtracting the retention time of an unretained compound (air retentiontimewith
...
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