ASTM D6733-01

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
An American National Standard
Designation:D6733–01
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 D 6733; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope fluid catalytic cracking (FCC) are analyzed, and the total olefin
content may not be accurate. Many of the olefins in spark
1.1 This test method covers the determination of individual
ignition fuels are at a concentration below 0.10 %; they are not
hydrocarbon components of spark-ignition engine fuels with
reported by this test method and may bias the total olefin
boiling ranges up to 225°C. Other light liquid hydrocarbon
results low.
mixtures typically encountered in petroleum refining opera-
1.5.1 Total olefins in the samples may be obtained or
tions,suchas,blendingstocks(naphthas,reformates,alkylates,
confirmed, or both, by Test Method D 1319 (volume %) or
and so forth) may also be analyzed; however, statistical data
other test methods, such as those based on multidimensional
was obtained only with blended spark-ignition engine fuels.
PONA type of instruments.
The tables in Annex A1 enumerate the components reported.
1.6 If water is or is suspected of being present, its concen-
Component concentrations are determined in the range from
tration may be determined, if desired, by the use of Test
0.10 to 15 mass %. The procedure may be applicable to higher
Method D 1744. Other compounds containing sulfur, nitrogen,
and lower concentrations for the individual components; how-
and so forth, may also be present, and may co-elute with the
ever, the user must verify the accuracy if the procedures are
hydrocarbons. If determination of these specific compounds is
used for components with concentrations outside the specified
required, it is recommended that test methods for these specific
ranges.
materials be used, such as Test Method D 5623 for sulfur
1.2 This test method is applicable also to spark-ignition
compounds.
engine fuel blends containing oxygenated components. How-
1.7 The values stated in SI units are to be regarded as the
ever, in this case, the oxygenate content must be determined by
standard. The values given in parentheses are provided for
Test Methods D 5599 or D 4815.
information only.
1.3 Benzene co-elutes with 1-methylcyclopentene. Benzene
1.8 This standard does not purport to address all of the
contentmustbedeterminedbyTestMethodD 3606orD 5580.
safety concerns, if any, associated with its use. It is the
1.4 Toluene co-elutes with 2,3,3-trimethylpentane. Toluene
responsibility of the user of this standard to establish appro-
contentmustbedeterminedbyTestMethodD 3606orD 5580.
priate safety and health practices and determine the applica-
1.5 Although a majority of the individual hydrocarbons
bility of regulatory limitations prior to use.
present are determined, some co-elution of compounds is
encountered. If this procedure is utilized to estimate bulk
2. Referenced Documents
hydrocarbon group-type composition (PONA) the user of such
2.1 ASTM Standards:
data should be cautioned that error may be encountered due to
D 1319 Test Method for Hydrocarbon Types in Liquid
co-elution and a lack of identification of all components
Petroleum Products by Fluorescent Indicator Adsorption
present. Samples containing significant amounts of naphthenic
D 1744 Test Method for Determination of Water in Liquid
(for example, virgin naphthas) constituents above n-octane
Petroleum Products by Karl Fisher Reagent
may reflect significant errors in PONA type groupings. Based
D 3606 Test Method for Determination of Benzene and
on the interlaboratory cooperative study, this procedure is
Toluene in Finished Motor and Aviation Gasoline by Gas
applicabletosampleshavingconcentrationsofolefinslessthan
Chromatography
20 mass %. However, significant interfering coelution with the
D 4057 Practice for Manual Sampling of Petroleum and
olefins above C is possible, particularly if blending compo-
Petroleum Products
nents or their higher boiling cuts such as those derived from
D 4420 Test Method forAromatics in Finished Gasoline by
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 05.01.
D02.04.0L on Gas Chromatographic Methods. Discontinued; see 1999 Annual Book of ASTM Standards, Vol 05.01.
Current edition approved Nov. 10, 2001. Published January 2002. Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6733–01
TABLE 1 Operating Conditions
Gas Chromatography
D 4815 Test Method for Determination of MTBE, ETBE, Temperatures Method 1 Method 2
TAME, DIPE, tertiary-Amyl Alcohol and C to C Alco-
Column initial isotherm, °C 35 10
1 4
Initial hold time, min. 10 15
hols in Gasoline by Gas Chromatography
Rate 1, °C/min. 1.1 1.3
D 5580 Test Method for Determination of Benzene, Tolu-
Final temperature 1, °C 114 70
ene, Ethylbenzene p/m-Xylene, o-Xylene, C and Heavier
Hold time 2, min. 0 0
Rate 2, °C/min 1.7 1.7
Aromatics and Total Aromatics in Finished Gasoline by
Final temperature 2, °C 250 250
Gas Chromatography
Final hold time 2, min. 5 20
D 5599 Test Method for Determination of Oxygenates in
Injector, °C 250 250
Detector, °C 280 280
Gasoline by Gas Chromatography and Oxygen Selective
Carrier gas helium pressure, kPA (psi) 207 (30) 190 (27)
Flame Ionization Detection
Flow rate (initial isotherm), mL/min. 0.9 0.7
D 5623 Test Method for Sulfur Compounds in Light Petro-
Average linear velocity, cm/s 22 21.5
Injection
leum Liquids by Gas Chromatography and Sulfur Selec-
Sample size, µL 0.5 0.3
tive Detection
Splitter vent–flow out, mL/min. 250 200
E 355 Practice for Gas Chromatography Terms and Rela-
tionships
6.3 Data Acquisition System—Any data system can be used
3. Terminology
with a requirement:
3.1 Definitions—This test method makes reference to many
6.3.1 Sampling rate of 10 Hz or more with a storage of
common gas chromatographic procedures, terms, and relation-
sampling data for later processing.
ships. Detailed definitions can be found in Practice E 355.
6.3.2 Capacity for at least 400 peaks/analysis.
4. Summary of Test Method 6.3.3 Identification of individual components from retention
time; software can be used to automatically identify the peaks
4.1 Representative samples of the petroleum liquid are
with the index system determined from Table A1.1 or Table
introduced into a gas chromatograph equipped with an open
A1.2.
tubular (capillary) column coated with specified stationary
6.4 Sampling—Two millilitres or more crimp-top vials and
phase(s). Helium carrier gas transports the vaporized sample
aluminum caps with polytetrafluoroethylene (PTFE)-lined
through the column in which it is partitioned into individual
septa are used to transfer the sample.
components, which are sensed with a flame ionization detector
6.5 Capillary Column—A 50 m fused silica capillary col-
as they elute from the end of the column. The detector signal
umn with an internal diameter of 0.2 mm, containing a 0.5 µm
is recorded digitally by way of an integrator or integrating
film thickness of bonded dimethylpolysiloxane phase is used.
computer. Each eluting component is identified by comparing
The features must be respected to reproduce the separation of
its retention time to those established by analyzing reference
the reference chromatogram. The column must meet the
standards or samples under identical conditions. The concen-
criteria of efficiency, resolution, and polarity defined in Section
tration of each component in mass % is determined by normal-
10.
ization of the peak areas after correction of selected compo-
nents with detector response factors. The unknown
7. Reagents and Materials
components are reported individually as well as a summary
7.1 Carrier Gas and Make-up, helium, 99.99 mol % pure.
total.
(Warning—Compressed gas under high pressure.)
5. Significance and Use
7.2 Fuel Gas, hydrogen, hydrocarbon free, 99.99 mol %
pure. (Warning—Compressed gas under high pressure. Ex-
5.1 Knowledge of the individual component composition
tremely flammable.)
(speciation) of gasoline fuels and blending stocks is useful for
7.3 Oxidizing Gas, air, 99 mol %. (Warning—Compressed
refinery quality control and product specification. Process
gas under high pressure.)
control and product specification compliance for many indi-
7.4 n-Pentane, 99+ mol % pure. (Warning—Extremely
vidual hydrocarbons may be determined through the use of this
flammable. Harmful if inhaled.)
test method.
7.5 n-Hexane, 99+ % mol % pure. (Warning—Extremely
flammable. Harmful if inhaled.)
6. Apparatus
7.6 n-Heptane, 99+ mol % pure. (Warning—Extremely
6.1 Instrumentation—A gas chromatograph capable of op-
flammable. Harmful if inhaled.)
erating under the conditions outlined in Table 1, equipped with
7.7 2-Methylheptane, 99+ mol % pure. (Warning—
a split injector, a carrier gas pressure control, and a flame
Extremely flammable. Harmful if inhaled.)
ionization detector which are required.
7.8 4-Methylheptane, 99+ mol % pure. (Warning—
6.2 Sample Introduction System—Manual or automatic liq-
Extremely flammable. Harmful if inhaled.)
uid syringe sample injection may be employed.
7.9 n-Octane, 99+ mol % pure. (Warning—Extremely
flammable. Harmful if inhaled.)
7.10 n-Dodecane, 99+ mol % pure. (Warning—Extremely
Annual Book of ASTM Standards, Vol 05.03.
Annual Book of ASTM Standards, Vol 14.02. flammable. Harmful if inhaled.)
D6733–01
7.11 Toluene, 99+ mol % pure. (Warning—Extremely
where:
flammable. Harmful if inhaled.)
n = number of theoretical plates,
Rt = retention time of normal octane, and
7.12 System Performance Mixture—Weighanequalamount
W = mid-height peak width of normal octane in the
of n-pentane, n-heptane, n-octane, n-dodecane, 0.5
same unit as retention time.
2-methylheptane, 4-methylheptane, and toluene. Dilute this
10.2.1.1 The number of theoretical plates must be greater
mixture in n-hexane to obtain a concentration of 2 mass % for
than 200 000.
each compound.
10.2.2 Resolution—Resolution is determined between the
8. Sampling peaks of 2-methylheptane and 4-methylheptane using Eq 2:
2~Rt – Rt !
8.1 Container Sampling—Samples shall be taken as de- ~a! ~b!
R 5 (2)
1.699 W 1 W !
scribedinPracticeD 4057forinstructionsonmanualsampling ~
0.5~a! 0.5~b!
into open container.
where:
8.2 The sample and a 2–mLvial must be cooled at 4°C. Part
Rt = retention time of 4-methylheptane,
(a)
ofthesampleistransferredto the vial up to 80 %ofitsvolume,
Rt = retention time of 2-methylheptane,
(b)
and aluminum cap with septum is crimped.
W = mid-height peak width of 4-methylheptane in
0.5(a)
the same unit as retention time, and
9. Preparation of Apparatus
W = mid-height peak width of 2-methylheptane in
0.5(b)
the same unit as retention time.
9.1 Installation—Install and condition column in accor-
dance with the supplier’s instruction. 10.2.2.1 The resolution must be equal to 4or greater than
1.20.
9.2 Operating Conditions—Two sets of operating condi-
10.2.3 Polarity—Polarity is defined by the McReynolds
tions are proposed in Table 1, the first with an initial column
constant of toluene, using Eq 3:
temperature above the ambient temperature, the second with a
sub-ambient column temperature profile. Adjust the operating
Rn 5 Ki – Ki (3)
tol ana squalane
conditions of the gas chromatograph to conform to the first or
where:
second method.
Ki = toluene Kovats index on Squalane at
squalane
9.3 Carrier Gas Pressure—Setacorrectcarriergaspressure
35°C = 742.6, and
using the system performance mixture such that the retention
Ki = toluene Kovats index on the analytical col-
ana
time of n-Heptane, n-Octane and n-Dodecane are between the
umn at 35°C.
values given in Table 2.
10.2.3.1 Toluene Kovats index is calculated using Eq 4:
log T8 – log T8
10. System Performance Evaluation R t R h
~ ! ~ !
Ki 5 700 1 100 (4)
ana S D
log T8 – log T8
R~o! R~h!
10.1 Evaluation of the column and linearity of the split
injection are carried out with a system performance mixture
where:
defined in 7.12 and with the column temperature conditions
T8 = adjusted retention time for toluene,
R(t)
defined in the following table.
T8 = adjusted retention time for n-heptane, and
R(h)
Initial temperature 35°C T8 = adjusted retention time for n-octane.
R(o)
Hold time 50 min.
10.2.3.2 Adjusted retention time of a peak is determined by
Final temperature 220°C
subtracting the retention time of an unretained compound (air
Hold time 20 min.
Rate 3°C/min.
or methane) from the retention time of the peak. The McRey-
nolds constant must be less than 10.
10.2 Column Evaluation—To perform the required separa-
10.2.4 Base Line Stability—Base line stability is calculated
tion, the column must meet three criteria of separation:
with the difference between area slices at the beginning and at
efficiency, resolution, and polarity.
the end of analysis, divided by the maximum area slice of
10.2.1 Effıciency—The number of theoretical plates is cal-
N-octane obtained with the system performance mixture.
culated with the normal octane peak using Eq 1:
10.2.4.1 Measurement of the Stability—Carry out one tem-
n 5 5.545~Rt/W ! (1)
0.5
perature programming defined in 10.1 without injecting any
sample. Subtract the area slices at the start of the analysis with
those corresponding to 120 min (average of three slices).
TABLE 2 Reference Retention Times of Normal Paraffins
10.2.4.2 Stability Standardization—Standardization is car-
NOTE—Minutes and tenths of a minute. ried out using the system performance mixture defined in 7.12
with the column temperature conditions defined in 10.1. The
Method 1 Method 1 Method 1 Method 2 Method 2 Method 2
value obtained in 10.2.4.1 is divided by the maximum area
n-Paraffins Lower Reference Upper Lower Reference Upper
Time Time Time Time Time Time slice of N-octane and multiplied by 100. The value obtained
n-Heptane 18.5 19.4 20.3 39.5 40.7 42.0
must be less than 2 %. If this is not the case, check for possible
n-Octane 32.0 33.0 34.0 57.0 57.8 59.0
leaks, or recondition the column according to the manufactur-
n-Dodecane 92.8 94.0 95.2 106.4 107.6 108.8
er’s recommendations.
D6733–01
10.3 Evaluation of the Linearity of the Split Inject
...