ASTM D4815-99
(Test Method)Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography
Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, <I>tertiary</I>-Amyl Alcohol and C<sub>1</sub> to C<sub>4</sub> Alcohols in Gasoline by Gas Chromatography
SCOPE
1.1 This test method is designed for the determination of ethers and alcohols in gasolines by gas chromatography. Specific compounds determined are: methyl tert -butylether (MTBE), ethyl tert -butylether (ETBE), tert -amylmethylether (TAME), diisopropylether (DIPE), methanol, ethanol, isopropanol, -propanol, isobutanol, tert -butanol, sec butanol, -butanol, and tert -pentanol ( tert -amylalcohol).
1.2 Individual ethers are determined from 0.1 to 20.0 mass percent. Individual alcohols are determined from 0.1 to 12.0 mass percent. Equations used to convert to mass percent oxygen and to volume % of individual compounds are provided.
1.3 Alcohol-based fuels such as M-85 and E-85, MTBE product, ethanol product and denatured alcohol are specifically excluded from this method. The methanol content of M-85 fuel is considered beyond the operating range of the system.
1.4 Benzene, while detected, cannot be quantified using this test method and must be analyzed by alternate methodology (Test Method D3606 or D4420).
1.5 SI (metric) units are preferred and used throughout this standard. Alternate units, in common usage, are also provided to increase clarity and aid the users of this test method.
1.6 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/i.
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Designation: D 4815 – 99 An American National Standard
Standard Test Method for
Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl
Alcohol and C to C Alcohols in Gasoline by Gas
1 4
Chromatography
This standard is issued under the fixed designation D 4815; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope ucts by Karl Fischer Reagent
D 3606 Test Method for the Determination of Benzene and
1.1 This test method covers the determination of ethers and
Toluene in Finished Motor and Aviation Gasoline by Gas
alcohols in gasolines by gas chromatography. Specific com-
Chromatography
pounds determined are methyl tert-butylether (MTBE), ethyl
D 4052 Test Method for Density and Relative Density of
tert-butylether (ETBE), tert-amylmethylether (TAME), diiso-
Liquids by Digital Density Meter
propylether (DIPE), methanol, ethanol, isopropanol,
D 4057 Practice for Manual Sampling of Petroleum and
n-propanol, isobutanol, tert-butanol, sec-butanol, n-butanol,
Petroleum Products
and tert-pentanol (tert-amylalcohol).
D 4307 Practice for Preparation of Liquid Blends for Use as
1.2 Individual ethers are determined from 0.1 to 20.0 mass
Analytical Standards
%. Individual alcohols are determined from 0.1 to 12.0 mass
D 4420 Test Method for Aromatics in Finished Gasoline by
%. Equations used to convert to mass % oxygen and to volume
Gas Chromatography
% of individual compounds are provided.
1.3 Alcohol-based fuels, such as M-85 and E-85, MTBE
3. Terminology
product, ethanol product, and denatured alcohol, are specifi-
3.1 Definitions of Terms Specific to This Standard:
cally excluded from this test method. The methanol content of
3.1.1 low volume connector—a special union for connecting
M-85 fuel is considered beyond the operating range of the
two lengths of tubing 1.6-mm inside diameter and smaller.
system.
Sometimes this is referred to as zero dead volume union.
1.4 Benzene, while detected, cannot be quantified using this
3.1.2 MTBE—methyl tert-butylether.
test method and must be analyzed by alternate methodology
3.1.3 ETBE—ethyl tert-butylether.
(see Test Method D 3606 or D 4420).
3.1.4 TAME—tert-amyl methylether.
1.5 The values stated in SI units are to be regarded as
3.1.5 DIPE—diisopropylether.
standard. Alternate units, in common usage, are also provided
3.1.6 tert-amyl alcohol—tert-pentanol.
to increase clarity and aid the users of this test method.
3.1.7 oxygenate—any oxygen-containing organic com-
1.6 This standard does not purport to address all of the
pound that can be used as a fuel or fuel supplement, for
safety concerns, if any, associated with its use. It is the
example, various alcohols and ethers.
responsibility of the user of this standard to establish appro-
3.1.8 split ratio—in capillary gas chromatography, the ratio
priate safety and health practices and determine the applica-
of the total flow of carrier gas to the sample inlet versus the
bility of regulatory limitations prior to use.
flow of the carrier gas to the capillary column, expressed by
2. Referenced Documents
split ratio 5 ~S 1 C!/C (1)
2.1 ASTM Standards:
where:
D 1298 Test Method for Density, Relative Density (Specific
S 5 flow rate at the splitter vent, and
Gravity), or API Gravity of Crude Petroleum and Liquid
C 5 flow rate at the column outlet.
Petroleum Products by Hydrometer Method
3.1.9 TCEP—1,2,3-tris-2-cyanoethoxypropane—a gas
D 1744 Test Method for Water in Liquid Petroleum Prod-
chromatographic liquid phase.
3.1.10 WCOT—a type of capillary gas chromatographic
1 column prepared by coating the inside of the capillary with a
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee thin film of stationary phase.
D02.04 on Hydrocarbon Analysis.
Current edition approved Nov. 10, 1999. Published January 2000. Originally
published as D 4815 – 89. Last previous edition D 4815 – 94a.
2 3
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4815
4. Summary of Test Method for these analyses, a gas chromatographic instrument, which
can be operated at the conditions given in Table 2 and has a
4.1 An appropriate internal standard, such as 1,2-
column switching and backflushing system equivalent to Fig.
dimethoxyethane (ethylene glycol dimethyl ether), is added to
1, has been found acceptable. Carrier gas flow controllers shall
the sample, which is then introduced into a gas chromatograph
be capable of precise control where the required flow rates are
equipped with two columns and a column switching valve. The
low (see Table 2). Pressure control devices and gages shall be
sample first passes onto a polar TCEP column, which elutes
capable of precise control for the typical pressures required.
lighter hydrocarbons to vent and retains the oxygenated and
6.1.1 Detector—A thermal conductivity detector or flame
heavier hydrocarbons.
ionization detector can be used. The system shall have suffi-
4.2 After methylcyclopentane, but before DIPE and MTBE
cient sensitivity and stability to obtain a recorder deflection of
elute from the polar column, the valve is switched to backflush
at least 2 mm at a signal-to-noise ratio of at least 5 to 1 for
the oxygenates onto a WCOT nonpolar column. The alcohols
0.005 volume % concentration of an oxygenate.
and ethers elute from the nonpolar column in boiling point
6.1.2 Switching and Backflushing Valve—A valve, to be
order, before elution of any major hydrocarbon constituents.
located within the gas chromatographic column oven, capable
4.3 After benzene and TAME elute from the nonpolar
of performing the functions described in Section 11 and
column, the column switching valve is switched back to its
illustrated in Fig. 1. The valve shall be of low volume design
original position to backflush the heavy hydrocarbons.
and not contribute significantly to chromatographic deteriora-
4.4 The eluted components are detected by a flame ioniza-
tion.
tion or thermal conductivity detector. The detector response,
6.1.2.1 Valco Model No. A 4C10WP, 1.6-mm ( ⁄16-in.)
proportional to the component concentration, is recorded; the
fittings. This particular valve was used in the majority of the
peak areas are measured; and the concentration of each
analyses used for the development of Section 15.
component is calculated with reference to the internal standard.
6.1.2.2 Valco Model No. C10W, 0.8-mm ( ⁄32-in.) fittings.
5. Significance and Use This valve is recommended for use with columns of 0.32-mm
inside diameter and smaller.
5.1 Ethers, alcohols, and other oxygenates can be added to
6.1.2.3 Some gas chromatographs are equipped with an
gasoline to increase octane number and to reduce emissions.
auxiliary oven, which can be used to contain the valve and
Type and concentration of various oxygenates are specified and
polar column. In such a configuration, the nonpolar column is
regulated to ensure acceptable commercial gasoline quality.
located in the main oven and the temperature can be adjusted
Drivability, vapor pressure, phase separation, exhaust, and
for optimum oxygenates resolution.
evaporative emissions are some of the concerns associated with
6.1.3 An automatic valve switching device must be used to
oxygenated fuels.
ensure repeatable switching times. Such a device should be
5.2 This test method is applicable to both quality control in
synchronized with injection and data collection times.
the production of gasoline and for the determination of
6.1.4 Injection System—The chromatograph should be
deliberate or extraneous oxygenate additions or contamination.
equipped with a splitting-type inlet device if capillary columns
6. Apparatus
or flame ionization detection are used. Split injection is
necessary to maintain the actual chromatographed sample size
6.1 Chromatograph—While any gas chromatographic sys-
within the limits of column and detector optimum efficiency
tem, which is capable of adequately resolving the individual
and linearity.
ethers and alcohols that are presented in Table 1, can be used
6.1.4.1 Some gas chromatographs are equipped with on-
column injectors and autosamplers, which can inject small
TABLE 1 Pertinent Physical Constants and Retention
samples sizes. Such injection systems can be used provided
Characteristics for TCEP/WCOT Column Set Conditions
as in Table 2 that sample size is within the limit of the column and detectors
optimum efficiency and linearity.
Relative Retention
Relative
Time
6.1.4.2 Microlitre syringes, automatic syringe injectors, and
Retention Molecular Density at
Component
Time, Min. Weight 15.56/
liquid sampling valves have been used successfully for intro-
(MTBE 5 (DME 5
15.56°C
1.00) 1.00)
ducing representative samples into the gas chromatographic
Water 2.90 0.58 0.43 18.0 1.000
inlet.
Methanol 3.15 0.63 0.46 32.0 0.7963
6.2 Data Presentation or Calculation, or Both:
Ethanol 3.48 0.69 0.51 46.1 0.7939
Isopropanol 3.83 0.76 0.56 60.1 0.7899
tert-Butanol 4.15 0.82 0.61 74.1 0.7922
TABLE 2 Chromatographic Operation Conditions
n-Propanol 4.56 0.90 0.67 60.1 0.8080
MTBE 5.04 1.00 0.74 88.2 0.7460 Temperatures Flows, mL/min Carrier Gas: Helium
sec-Butanol 5.36 1.06 0.79 74.1 0.8114
A
Column Oven 60 to injector 75 Sample size, μL 1.0–3.0
DIPE 5.76 1.14 0.85 102.2 0.7282
Injector, °C 200 Column 5 Split ratio 15:1
Isobutanol 6.00 1.19 0.88 74.1 0.8058
Detector—TCD, °C 200 Auxillary 3 Backflush, min 0.2–0.3
ETBE 6.20 1.23 0.91 102.2 0.7452
—FID, °C 250 Makeup 18 Valve reset time 8–10 min
tert-Pentanol 6.43 1.28 0.95 88.1 0.8170
Valve °C 60 Total Analysis time 18–20 min
1,2-Dimethoxyethane 6.80 1.35 1.00 90.1 0.8720
A
(DME)
Sample size must be adjusted so that alcohols in the range of 0.1 to 12.0 mass
n-Butanol 7.04 1.40 1.04 74.1 0.8137 % and ethers in the range of 0.1 to 20.0 mass % are eluted from the column and
TAME 8.17 1.62 1.20 102.2 0.7758 measured linearly at the detector. A sample size of 1.0 μL has been introduced in
most cases.
D 4815
boiling point range. The oxygenates and remaining hydrocar-
bons are backflushed onto the nonpolar column in 6.3.2. Any
column with equivalent or better chromatographic efficiency
and selectivity to that described in 6.3.1.1 can be used. The
column shall perform at the same temperature as required for
the column in 6.3.2, except if located in a separate auxiliary
oven as in 6.1.2.3.
6.3.1.1 TCEP Micro-Packed Column, 560 mm (22 in.) by
1.6-mm ( ⁄16-in.) outside diameter by 0.76-mm (0.030-in.)
inside diameter stainless steel tube packed with 0.14 to 0.15 g
of 20 % (mass/mass) TCEP on 80/100 mesh Chromosorb
P(AW). This column was used in the cooperative study to
provide the precision and bias data referred to in Section 15.
6.3.2 NonPolar (Analytical) Column—Any column with
equivalent or better chromatographic efficiency and selectivity
to that described in 6.3.2.1 and illustrated in Fig. 2 can be used.
6.3.2.1 WCOT Methyl Silicone Column, 30-m (1181-in.)
long by 0.53-mm (0.021-in.) inside diameter fused silica
WCOT column with a 2.6-μm film thickness of cross-linked
methyl siloxane. This column was used in the cooperative
study to provide the precision and bias data referred to in
Section 15.
7. Reagents and Materials
7.1 Carrier Gas—Carrier gas appropriate to the type of
detector used. Helium has been used successfully. The mini-
mum purity of the carrier gas used must be 99.95 mol %.
7.2 Standards for Calibration and Identification—
Standards of all components to be analyzed and the internal
standard are required for establishing identification by reten-
tion time as well as calibration for quantitative measurements.
These materials shall be of known purity and free of the other
components to be analyzed. (Warning—These materials are
flammable and can be harmful or fatal if ingested or inhaled.)
7.3 Methylene Chloride, used for column preparation, re-
agent grade, free of nonvolatile residue. (Warning—Harmful
if inhaled. High concentrations may cause unconsciousness or
death.)
8. Preparation of Column Packings
8.1 TCEP Column Packing:
8.1.1 Any satisfactory method used in the practice of the art
that will produce a column capable of retaining the C1 to C4
alcohols and MTBE, ETBE, DIPE, and TAME from compo-
nents of the same boiling point range in a gasoline sample. The
FIG. 1 Analysis of Oxygenates in Gasoline Schematic of
following procedure has been used successfully.
Chromatographic System
8.1.2 Completely dissolve 10 g of TCEP in 100 mL of
methylene chloride. Next add 40 g of 80/100 mesh Chro-
6.2.1 Recorder—A recording potentiometer or equivalent
mosorb P(AW) to the TCEP solution. Quickly transfer this
with a full-scale deflection of 5 mV or less can be used to
mixture to a drying dish, in a fume hood, without scraping any
monitor detector signal. Full-scale response time should be 1 s
of the residual packing from the sides of the container.
or less with sufficient sensitivity and stability to meet the
Constantly, but gently, stir the packing until all of the solvent
requirements of 6.1.1.
has evaporated. This column packing can be used immediately
6.2.2 Integrator or Computer—Means shall be provided for
to prepare the TCEP column.
determining the detector response. Peak heights or areas can be
measured by computer, electronic integration, or manual tech-
9. Sampling
niques.
9.1 Every effort should be made to ensure that the sample is
6.3 Columns, Two as Follows:
6.3.1 Polar Column—This column performs a presepara-
tion of the oxygenates from volatile hydrocarbons in the same Available from Hewlett Packard Co., Avondale, PA.
D 4815
FIG. 2 Analyses of Oxygenates in Gasoline Example Chromatogram Showing Oxygenates
representative of the fuel source from which it is taken. Follow broadening will occur.
the recommendations of Practice D 4057, or its equivalent,
11.2 Adjust the operating conditions to those listed in Table
when obtaining samples from bulk storage or pipelines.
2, but do not turn on the detector circuits. Check the system for
9.2 Upon receipt in the laboratory, chill the sample in its
leaks before proceeding further.
original container to 0 to 5°C (32 to 40°F) before any
11.2.1 If different polar and nonpolar columns or capillary
subsampling is performed.
columns of smaller
...
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