Designation: D4815 − 15b

Standard Test Method for

Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl
Alcohol and C1 to C4 Alcohols in Gasoline by Gas
Chromatography1
This standard is issued under the fixed designation D4815; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.

1. Scope* cally excluded from this test method. The methanol content of
1.1 This test method covers the determination of ethers and M-85 fuel is considered beyond the operating range of the
alcohols in gasolines by gas chromatography. Specific com- system.
pounds determined are methyl tert-butylether (MTBE), ethyl 1.5 Benzene, while detected, cannot be quantified using this
tert-butylether (ETBE), tert-amylmethylether (TAME), diiso- test method and must be analyzed by alternate methodology
propylether (DIPE), methanol, ethanol, isopropanol,
(see Test Method D3606).
n-propanol, isobutanol, tert-butanol, sec -butanol, n-butanol,
and tert-pentanol (tert-amylalcohol). 1.6 The values stated in SI units are to be regarded as
1.2 Individual ethers are determined from 0.20 mass % to standard. Alternate units, in common usage, are also provided
20.0 mass %. Individual alcohols are determined from to increase clarity and aid the users of this test method.
0.20 mass % to 12.0 mass %. Equations used to convert to 1.7 This standard does not purport to address all of the
mass % oxygen and to volume % of individual compounds are safety concerns, if any, associated with its use. It is the
provided. At concentrations <0.20 mass %, it is possible that responsibility of the user of this standard to establish appro-
hydrocarbons may interfere with several ethers and alcohols. priate safety and health practices and determine the applica-
The reporting limit of 0.20 mass % was tested for gasolines
bility of regulatory limitations prior to use.
containing a maximum of 10 volume % olefins. It may be
possible that for gasolines containing >10 volume % olefins,
the interference may be >0.20 mass %. Annex A1 gives a 2. Referenced Documents
chromatogram showing the interference observed with a gaso- 2.1 ASTM Standards:2
line containing 10 volume % olefins. D1298 Test Method for Density, Relative Density, or API
1.3 This test method includes a relative bias correlation for Gravity of Crude Petroleum and Liquid Petroleum Prod-
ethanol in spark-ignition engine fuels for the U.S. EPA ucts by Hydrometer Method
regulations reporting based on Practice D6708 accuracy assess- D1744 Test Method for Water in Liquid Petroleum Products
ment between Test Method D4815 and Test Method D5599 as by Karl Fischer Reagent3
a possible Test Method D4815 alternative to Test Method D3606 Test Method for Determination of Benzene and
D5599. The Practice D6708 derived correlation equation is Toluene in Finished Motor and Aviation Gasoline by Gas
only applicable for ethanol in fuels in the concentration range Chromatography
from 2.28 % to 14.42 % by mass as measured by Test Method D4052 Test Method for Density, Relative Density, and API
D4815. The applicable Test Method D5599 range for ethanol is Gravity of Liquids by Digital Density Meter
from 2.16 % to14.39 % by mass as reported by Test Method D4057 Practice for Manual Sampling of Petroleum and
D5599. Petroleum Products
1.4 Alcohol-based fuels, such as M-85 and E-85, MTBE D4307 Practice for Preparation of Liquid Blends for Use as
product, ethanol product, and denatured alcohol, are specifi- Analytical Standards
1
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
2
Subcommittee D02.04.0L on Gas Chromatography Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2015. Published December 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1989. Last previous edition approved in 2015 as D4815 – 15a. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4815-15B. the ASTM website.

*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

1
 D4815 − 15b
D4420 Test Method for Determination of Aromatics in TABLE 1 Pertinent Physical Constants and Retention
Finished Gasoline by Gas Chromatography (Withdrawn Characteristics for TCEP/WCOT Column Set Conditions
as in Table 2
2004)3
Relative Retention Relative
D5599 Test Method for Determination of Oxygenates in Time
Retention Molecular Density at
Gasoline by Gas Chromatography and Oxygen Selective Component
Time, Min. (MTBE = (DME = Mass 15.56/
Flame Ionization Detection 1.00) 1.00) 15.5 6°C
D6708 Practice for Statistical Assessment and Improvement Water 2.90 0.58 0.43 18.0 1.000
of Expected Agreement Between Two Test Methods that Methanol 3.15 0.63 0.46 32.0 0.7963
Ethanol 3.48 0.69 0.51 46.1 0.7939
Purport to Measure the Same Property of a Material Isopropanol 3.83 0.76 0.56 60.1 0.7899
tert-Butanol 4.15 0.82 0.61 74.1 0.7922
3. Terminology n-Propanol 4.56 0.90 0.67 60.1 0.8080
MTBE 5.04 1.00 0.74 88.2 0.7460
3.1 Definitions of Terms Specific to This Standard: sec-Butanol 5.36 1.06 0.79 74.1 0.8114
3.1.1 low volume connector—a special union for connecting DIPE 5.76 1.14 0.85 102.2 0.7282
Isobutanol 6.00 1.19 0.88 74.1 0.8058
two lengths of tubing 1.6 mm inside diameter and smaller. ETBE 6.20 1.23 0.91 102.2 0.7452
Sometimes this is referred to as zero dead volume union. tert-Pentanol 6.43 1.28 0.95 88.1 0.8170
1,2-Dimethoxyethane 6.80 1.35 1.00 90.1 0.8720
3.1.2 oxygenate—any oxygen-containing organic compound (DME)
that can be used as a fuel or fuel supplement, for example, n-Butanol 7.04 1.40 1.04 74.1 0.8137
TAME 8.17 1.62 1.20 102.2 0.7758
various alcohols and ethers.
3.1.3 split ratio—in capillary gas chromatography, the ratio
of the total flow of carrier gas to the sample inlet versus the
flow of the carrier gas to the capillary column, expressed by 4.3 After benzene and TAME elute from the nonpolar
split ratio 5 ~ S1C ! /C (1)
column, the column switching valve is switched back to its
original position to backflush the heavy hydrocarbons.
where:
4.4 The eluted components are detected by a flame ioniza-
S = flow rate at the splitter vent, and tion or thermal conductivity detector. The detector response,
C = flow rate at the column outlet. proportional to the component concentration, is recorded; the
3.1.4 tert-amyl alcohol—tert -pentanol. peak areas are measured; and the concentration of each
3.2 Acronyms: component is calculated with reference to the internal standard.
3.2.1 DIPE—diisopropylether.
5. Significance and Use
3.2.2 ETBE—ethyl tert-butylether.
5.1 Ethers, alcohols, and other oxygenates can be added to
3.2.3 MTBE—methyl tert-butylether. gasoline to increase octane number and to reduce emissions.
3.2.4 TAME—tert-amyl methylether. Type and concentration of various oxygenates are specified and
3.2.5 TCEP—1,2,3-tris-2-cyanoethoxypropane—a gas regulated to ensure acceptable commercial gasoline quality.
chromatographic liquid phase. Drivability, vapor pressure, phase separation, exhaust, and
evaporative emissions are some of the concerns associated with
3.2.6 WCOT—a type of capillary gas chromatographic col-
oxygenated fuels.
umn prepared by coating the inside of the capillary with a thin
film of stationary phase. 5.2 This test method is applicable to both quality control in
the production of gasoline and for the determination of
4. Summary of Test Method deliberate or extraneous oxygenate additions or contamination.
4.1 An appropriate internal standard, such as 1,2- 6. Apparatus
dimethoxyethane (ethylene glycol dimethyl ether), is added to
6.1 Chromatograph—While any gas chromatographic
the sample, which is then introduced into a gas chromatograph
system, which is capable of adequately resolving the individual
equipped with two columns and a column switching valve. The
ethers and alcohols that are presented in Table 1, can be used
sample first passes onto a polar TCEP column, which elutes
for these analyses, a gas chromatographic instrument, which
lighter hydrocarbons to vent and retains the oxygenated and
can be operated at the conditions given in Table 2 and has a
heavier hydrocarbons.
column switching and backflushing system equivalent to Fig.
4.2 After methylcyclopentane, but before DIPE and MTBE 1, has been found acceptable. Carrier gas flow controllers shall
elute from the polar column, the valve is switched to backflush be capable of precise control where the required flow rates are
the oxygenates onto a WCOT nonpolar column. The alcohols low (see Table 2). Pressure control devices and gages shall be
and ethers elute from the nonpolar column in boiling point capable of precise control for the typical pressures required.
order, before elution of any major hydrocarbon constituents. 6.1.1 Detector—A thermal conductivity detector or flame
ionization detector can be used. The system shall have suffi-
cient sensitivity and stability to obtain a recorder deflection of
3
The last approved version of this historical standard is referenced on at least 2 mm at a signal-to-noise ratio of at least 5 to 1 for
www.astm.org. 0.005 volume % concentration of an oxygenate.

2
 D4815 − 15b

NOTE 1—Detector B is optional and used to simplify setting cut times.

FIG. 1 Analysis of Oxygenates in Gasoline Schematic of Chromatographic System

TABLE 2 Chromatographic Operation Conditions or flame ionization detection are used. Split injection is
Temperatures Flows, mL/min Carrier Gas: Helium necessary to maintain the actual chromatographed sample size
Column Oven 60 to injector 75 Sample size, µLA 1.0–3.0 within the limits of column and detector optimum efficiency
Injector, °C 200 Column 5 Split ratio 15:1 and linearity.
Detector—TCD, °C 200 Auxiliary 3 Backflush, min 0.2–0.3
—FID, °C 250 Makeup 18 Valve reset time 8–10 min 6.1.4.1 Some gas chromatographs are equipped with on-
Valve °C 60 Total Analysis time 18–20 min column injectors and autosamplers, which can inject small
A
Sample size must be adjusted so that alcohols in the range of 0.1 mass % to samples sizes. Such injection systems can be used provided
12.0 mass % and ethers in the range of 0.1 mass % to 20.0 mass % are eluted that sample size is within the limit of the column and detectors
from the column and measured linearly at the detector. A sample size of 1.0 µL has
been introduced in most cases. optimum efficiency and linearity.
6.1.4.2 Microlitre syringes, automatic syringe injectors, and
liquid sampling valves have been used successfully for intro-
ducing representative samples into the gas chromatographic
6.1.2 Switching and Backflushing Valve—A valve, to be inlet.
located within the gas chromatographic column oven, capable 6.2 Data Presentation or Calculation, or Both:
of performing the functions described in Section 11 and
6.2.1 Recorder—A recording potentiometer or equivalent
illustrated in Fig. 1. The valve shall be of low volume design
with a full-scale deflection of 5 mV or less can be used to
and not contribute significantly to chromatographic deteriora-
monitor detector signal. Full-scale response time should be 1 s
tion.
or less with sufficient sensitivity and stability to meet the
6.1.2.1 Valco Model No. A 4C10WP, 1.6 mm (1⁄16 in.) fit-
requirements of 6.1.1.
tings. This particular valve was used in the majority of the
6.2.2 Integrator or Computer—Means shall be provided for
analyses used for the development of Section 15.
determining the detector response. Peak heights or areas can be
6.1.2.2 Valco Model No. C10W, 0.8 mm (1⁄32 in.) fittings.
measured by computer, electronic integration, or manual tech-
This valve is recommended for use with columns of 0.32 mm
niques.
inside diameter and smaller.
6.1.2.3 Some gas chromatographs are equipped with an 6.3 Columns, Two as Follows:
auxiliary oven, which can be used to contain the valve and 6.3.1 Polar Column—This column performs a preseparation
polar column. In such a configuration, the nonpolar column is of the oxygenates from volatile hydrocarbons in the same
located in the main oven and the temperature can be adjusted boiling point range. The oxygenates and remaining hydrocar-
for optimum oxygenates resolution. bons are backflushed onto the nonpolar column in 6.3.2. Any
6.1.3 An automatic valve switching device must be used to column with equivalent or better chromatographic efficiency
ensure repeatable switching times. Such a device should be and selectivity to that described in 6.3.1.1 can be used. The
synchronized with injection and data collection times. column shall perform at the same temperature as required for
6.1.4 Injection System—The chromatograph should be the column in 6.3.2, except if located in a separate auxiliary
equipped with a splitting-type inlet device if capillary columns oven as in 6.1.2.3.

3
 D4815 − 15b

FIG. 2 Analyses of Oxygenates in Gasoline Example Chromatogram Showing Oxygenates

6.3.1.1 TCEP Micro-Packed Column, 560 mm (22 in.) by nents of the same boiling point range in a gasoline sample. The
1.6 mm (1⁄16 in.) outside diameter by 0.76 mm (0.030 in.) following procedure has been used successfully.
inside diameter stainless steel tube packed with 0.14 g to 0.15 g 8.1.2 Completely dissolve 10 g of TCEP in 100 mL of
of 20 % (mass/mass) TCEP on 80/100 mesh Chromosorb methylene chloride. Next add 40 g of 80/100 mesh Chromo-
P(AW). This column was used in the cooperative study to sorb P(AW) to the TCEP solution. Quickly transfer this mixture
provide the precision and bias data referred to in Section 15. to a drying dish, in a fume hood, without scraping any of the
6.3.2 Nonpolar (Analytical) Column—Any column with residual packing from the sides of the container. Constantly,
equivalent or better chromatographic efficiency and selectivity but gently, stir the packing until all of the solvent has
to that described in 6.3.2.1 and illustrated in Fig. 2 can be used. evaporated. This column packing can be used immediately to
6.3.2.1 WCOT Methyl Silicone Column, 30 m (1181 in.) prepare the TCEP column.
long by 0.53 mm (0.021 in.) inside diameter fused silica
WCOT column with a 2.6 µm film thickness of cross-linked 9. Sampling
methyl siloxane. This column was used in the cooperative 9.1 Every effort should be made to ensure that the sample is
study to provide the precision and bias data referred to in representative of the fuel source from which it is taken. Follow
Section 15. the recommendations of Practice D4057, or its equivalent,
when obtaining samples from bulk storage or pipelines.
7. Reagents and Materials
9.2 Upon receipt in the laboratory, chill the sample in its
7.1 Carrier Gas—Carrier gas appropriate to the type of
original container to 0 °C to 5 °C (32 °F to 40 °F) before any
detector used. Helium has been used successfully. The mini-
subsampling is performed.
mum purity of the carrier gas used must be 99.95 mol %.
9.3 If necessary, transfer the chilled sample to a vapor tight
7.2 Standards for Calibration and Identification—Standards
container and store at 0 °C to 5 °C (32 °F to 40 °F) until needed
of all components to be analyzed and the internal standard are
for analysis.
required for establishing identification by retention time as well
as calibration for quantitative measurements. These materials
10. Preparation of Micro-Packed TCEP Column
shall be of known purity and free of the other components to be
analyzed. (Warning—These materials are flammable and can 10.1 Wash a straight 560 mm length of 1.6 mm outside
be harmful or fatal if ingested or inhaled.) diameter (0.76 mm inside diameter) stainless steel tubing with
methanol and dry with compressed nitrogen.
7.3 Methylene Chloride, used for column preparation, re-
agent grade, free of nonvolatile residue. (Warning—Harmful 10.2 Insert six to twelve strands of silvered wire, a small
if inhaled. High concentrations may cause unconsciousness or mesh screen, or stainless steel frit inside one end of the tube.
death.) Slowly add 0.14 g to 0.15 g of packing material to the column
and gently vibrate to settle the packing inside the column.
8. Preparation of Column Packings When strands of wire are used to retain the packing material
8.1 TCEP Column Packing: inside the column, leave 6.0 mm (0.25 in.) of space at the top
8.1.1 Any satisfactory method used in the practice of the art of the column.
that will produce a column capable of retaining the C1 to C4 10.3 Column Conditioning—Both the TCEP and WCOT
alcohols and MTBE, ETBE, DIPE, and TAME from compo- columns are to be briefly conditioned before use. Connect the

4
 D4815 − 15b
columns to the valve (see 11.1) in the chromatographic oven. baseline and the system is ready for another analysis. The
Adjust the carrier gas flows as in 11.3 and place the valve in the chromatogram should appear similar to the one illustrated in
RESET position. After several minutes, increase the column Fig. 2.
oven temperature to 120 °C and maintain these conditions for 11.5.1.1 Ensure that the BACKFLUSH time is sufficient to
5 min to 10 min. Cool the columns below 60 °C before quantitatively transfer the higher concentrations of the ethers,
shutting off the carrier flow. specifically MTBE, into the nonpolar column.
11.5.2 It is necessary to optimize the valve BACKFLUSH
11. Preparation of Apparatus and Establishment of time by analyzing a standard blend containing oxygenates. The
Conditions correct BACKFLUSH time is determined experimentally by
11.1 Assembly—Connect the WCOT column to the valve using valve switching times between 0.20 min and 0.35 min.
system using low volume connectors and narrow bore tubing. When the valve is switched too soon, C5 and lighter hydro-
It is important to minimize the volume of the chromatographic carbons are backflushed and are co-eluted in the C4 alcohol
system that comes in contact with the sample; otherwise, peak section of the chromatogram. When the valve BACKFLUSH is
broadening will occur. switched too late, part or all of the ether component (MTBE,
ETBE, or TAME) is vented, resulting in an incorrect ether
11.2 Adjust the operating conditions to those listed in Table measurement.
2, but do not turn on the detector circuits. Check the system for 11.5.2.1 DIPE may require a BACKFLUSH time slightly
leaks before proceeding further. shorter than the other ethers. The system may require reopti-
11.2.1 If different polar and nonpolar columns or capillary mization if the analysis of DIPE is required.
columns of smaller ID, or both, are used it can be necessary to 11.5.3 To facilitate setting BACKFLUSH time, the column
use different optimum flows and temperatures. vent in Fig. 1 can be connected to a second detector (TCD or
11.3 Flow Rate Adjustment: FID), as described in Test Method D4420, and used to set
11.3.1 Attach a flow measuring device to the column vent BACKFLUSH TIME based on the oxygenates standard con-
with the valve in the RESET position and adjust the pressure to taining the ethers of interest.
the injection port to give 5.0 mL ⁄ min flow (14 psig). Soap
bubble flow meters are suitable. 12. Calibration and Standardization
11.3.2 Attach a flow measuring device to the split injector 12.1 Identification—Determine the retention time of each
vent and adjust the flow from the split vent using the A flow component either by injecting small amounts separately, in
controller to give a flow of 70 mL ⁄ min. Recheck the column known mixtures, or by comparing the relative retention times
vent flow set in 11.3.1 and adjust if necessary. with those in Table 1.
11.3.3 Switch the valve to the BACKFLUSH position and 12.1.1 To ensure minimum interference from hydrocarbons,
adjust the variable restrictor to give the same column vent flow it is strongly recommended that a fuel devoid of oxygenates be
set in 11.3.1. This is necessary to minimize flow changes when chromatographed to determine the level of any hydrocarbon
the valve is switched. interference.
11.3.4 Switch the valve to the inject position RESET and
adjust the B flow controller to give a flow of 3.0 to 3.2 mL/min 12.2 Preparation of Calibration Samples—Prepare multi-
at the detector exit. When required for the particular instru- component calibration standards of the oxygenates and con-
mentation used, add makeup flow or TCD switching flow to centration ranges of interest, by mass, in accordance with
give a total of 21 mL/min at the detector exit. Practice D4307.
12.2.1 For each oxygenate, prepare a minimum of five
11.4 When a thermal conductivity detector is used, turn on calibration standards spanning the range of the oxygenate in
the filament current and allow the detector to equilibrate. When the samples. As an example, for full range calibration, 0.1, 0.5,
a flame ionization detector is used, set the hydrogen and air 2, 5, 10, 15, and 20 mass % of each oxygenate may be used.
flows and ignite the flame. 12.2.2 Before preparing the standards, determine the purity
11.5 Determine the Time to Backflush—The time to back- of the oxygenate stocks and make corrections for the impurities
flush will vary slightly for each column system and must be found. Whenever possible, use stocks of at least 99.9 % purity.
determined experimentally as follows. The start time of the Correct the purity of the components for water content,
integrator and valve timer must be synchronized with the determined by Test Method D1744.
injection to accurately reproduce the backflush time. 12.2.3 To minimize evaporation of light components, chill
11.5.1 Initially assume a valve BACKFLUSH time of all chemicals and gasoline used to prepare standards.
0.23 min. With the valve RESET, inject 1 µL to 3 µL of a blend 12.2.4 Prepare standards by transferring a fixed volume of
containing at least 0.5 % or greater oxygenates (see 7.3), and oxygenates, using pipettes or eye droppers (for volumes below
simultaneously begin timing the analysis. At 0.23 min, rotate 1 volume %), to 100 mL volumetric flasks or septum capped
the valve to the BACKFLUSH position and leave it there until vials as follows. Cap and record the tare weight of the
the complete elution of TAME is realized. Record this time as volumetric flask or vial to 0.1 mg. Remove the cap and
the RESET time, which is the time at which the valve is carefully add the oxygenate to the flask or vial. Do not
returned to the RESET position. When all of the remaining contaminate with sample the part within the flask or vial that
hydrocarbons are backflushed, the signal will return to a stable contacts the cap. Cap and record the net mass (Wi) to 0.1 mg of

5
 D4815 − 15b
TABLE 3 Example Calculation of Correlation Coefficient
Xi Yi x = Xi − x̄ y = Yi − ȳ xy x2 y2
1.0 0.5 −2.0 −1.0 2.0 4.0 1.0
2.0 1.0 −1.0 −0.5 0.5 1.0 0.25
3.0 1.5 0.0 0.0 0.0 0.0 0.0
4.0 2.0 +1.0 0.5 0.5 1.0 0.25
5.0 2.5 +2.0 1.0 2.0 4.0 1.0
x̄ = 3.0 ȳ = 1.5 (^xy) ^x2 = 10.0 ^y2 = 2.5
2 = 25.0

s o xyd 2 25.0
r2 5 5 5 1.0
s o x 2 ds o y 2 d s 10.0ds 2.5d

the oxygenate added. Repeat the addition and weighing proce-

dure for each oxygenate of interest. Similarly, add 5 mL of the
internal standard (DME) and record its net mass (Ws) to
0.1 mg.
12.2.5 Dilute each standard to 100.0 mL with oxygenate-
free gasoline or a mixture of hydrocarbons, such as isooctane/
mixed xylenes (63.35 volume %). Do not exceed 30 volume %
for all oxygenates, including the internal standard added. Store
the capped calibrations standards below 5 °C (40 °F) when not
in use.
12.3 Standardization:
12.3.1 Run the calibration standards and establish the cali- FIG. 3 A Least-Squares Fit Calibration for MTBE
bration curve for each oxygenate. Plot the response ratio (rspi):
rspi 5 ~ Ai/As! (2)
where:
where: (rspi) = response ratio for oxygenate i (y-axis),
Ai = area of oxygenate, and mi = slope of linear equation for oxygenate i,
As = area of internal standard. amti = amount ratio for oxygenate i (x-axis), and
as the y-axis versus the amount ratio (amti): bi = y-axis intercept.
amti 5 ~ Wi/Ws! (3) 12.3.4 The values mi and bi are calculated as follows:
where: mi 5 ( xy/ ( x 2
(8)
Wi = mass of oxygenate, and and
Ws = mass of internal standard.
b i 5 ȳ 2 m i x̄ (9)
as the x-axis calibration curves for each oxygenate. Check
the correlation r2 value for each oxygenate calibration. The r2 12.3.5 For the example in Table 3:
value should be at least 0.99 or better. r2 is calculated as m i 5 5/10 5 0.5 (10)
follows:
and
2
~ ( xy! 2 b i 5 ȳ 2 m i x̄ 5 1.5 2 ~ 0.5!~ 3 ! 5 0 (11)
r 5 (4)
~ ( x 2 !~ ( y 2 !
Therefore, the least-squares fit (see Eq 7) for the above
where: example in Table 3 is:
x 5 X i 2 x̄ (5) ~ rspi ! 5 0.5 amti 10 (12)
y 5 Y i 2 ȳ (6) NOTE 1—Normally the bi value is not zero and may be either positive
or negative. Fig. 3 gives an example of a linear least-squares fit for MTBE
and: and the resulting equation in the form of Eq 7.
Xi = amti ratio data point, 12.3.6 For an optimum calibration, the absolute value of the
X = average values for all (amti) data points, y-intercept bi must be at a minimum. In this case, Ai approaches
Yi = corresponding rspi ratio data point, and zero when wi is less than or equal to 0.1 mass %. The equation
ȳ = average values for all (rspi) data points. to determine the mass % oxygenate i or wi, reduces to Eq 13.
12.3.2 Table 3 gives an example on the calculation of r2 for The y-intercept can be tested using Eq 13:
an ideal data set Xi and Yi: w i 5 ~ b i /m i !~ W s /W g ! 100 % (13)
12.3.3 For each oxygenate i calibration data set, obtain the
linear least-squares fit equation in the form: where:
wi = mass % oxygenate i, where wi is ≤0.1 mass %,
~ rspi ! 5 ~ m i !~ amti ! 1b i (7)

6
 D4815 − 15b

Ws = mass of internal standard added to the gasoline rspi 5 ~ m i !~ amti ! 1b i (15)

samples, g, and where:
Wg = mass of gasoline samples, g.
NOTE 2—Since in practice W and Wg vary slightly from sample to
mi = slope of the linear fit,
s
sample, use average values. bi = y-intercept, and
amti = amount ratio as defined by Eq 3.
12.3.7 The following gives an example of the calculation
for the y-intercept (bi) test using Fig. 3 for oxygenate i (MTBE) or
for which bi = 0.015 and mi = 1.83. From 13.1, a typical Wi
sample preparation may contain approximately Ws = 0.4 g amti 5 5 ~ rspi 2 b i ! /m i (16)
Ws
(0.5 mL) of internal standard and approximately Wg = 7 g
(9.5 mL) of a gasoline sample. Substituting these values into or
Eq 13 yields: Wi 5 @ ~ rspi 2 b i ! /m i # Ws (17)
w i 5 ~ 0.015/1.83!~ 0.4 g/7 g ! 100 % (14) 5 @ ~ Ai/As 2 b i ! /m i # Ws (18)

50.05 mass % To obtain mass % (w i) results for each oxygenate:

12.3.8 Since wi is less than 0.1 mass %, the y-intercept bi Wi~ 100!
wi 5 (19)
has an acceptable value for MTBE. Similarly, determine wi for Wg
all other oxygenates. For all oxygenates, wi must be less than where:
or equal to 0.1 mass %. If any of the wi values are greater than Wg = weight of gasoline sample.
0.1 mass %, rerun the calibration procedure for oxygenate i or
check instrument parameters and hardware or check for hydro- 14.2 Report the mass fraction of each oxygenate to the
carbon interferences. nearest 0.01 %. For concentrations less than the mass fraction
of 0.20 %, report as “not detected.”
13. Procedure 14.3 Volumetric Concentration of Oxygenates—If the volu-
13.1 Preparation of Sample—Transfer 0.5 mL of internal metric concentration of each oxygenate is desired, calculate the
standard (Ws) by a volumetric pipette into a tared and capped volumetric concentration in accordance with Eq 20:
10 mL volumetric flask. Record weight to nearest 0.1 mg.
Record the net mass of the internal standard added. Retare the
capped flask. Fill the 10 mL volumetric flask to volume with
V i 5 wi S D
Df
Di
(20)

sample, cap, and record the net mass (Wg) to the nearest 0.1 mg where:
of the sample added. Mix thoroughly and inject into the gas wi = mass % of each oxygenate, as determined using Eq 19,
chromatograph. If using an automatic sampler, then transfer an Vi = volume % of each oxygenate to be determined,
aliquot of the solution into a glass gas chromatographic (GC) Di = relative density at 15.56 °C (60 °F) of the individual
vial. Seal the GC vial with a TFE-fluorocarbon-lined septum. If oxygenate, as found in Table 1, and
the sample is not immediately analyzed, store below 5 °C Df = relative density of the fuel under study, as determined
(40 °F). by Test Method D1298 or D4052.
13.2 Chromatographic Analysis—Introduce a representative 14.4 Report the volume % of each oxygenate to the nearest
aliquot of the sample, containing internal standard, into the gas 0.01 volume %.
chromatograph, using the same technique and sample size as
14.5 Mass % Oxygen—To determine the oxygen content of
used for the calibration analysis. An injection volume of 1.0 µL
the fuel, convert and sum the oxygen contents of all oxygen-
to 3.0 µL with a 15:1 split ratio has been used successfully.
ated components determined above in accordance with the
Start recording and integrating devices in synchronization
following equation:
with sample introduction. Obtain a chromatogram or inte-
grated peak report, or both, which displays the retention times w i 3 16.0 3 N i
and integrated area of each detected component.
W tot 5 ( Mi
(21)

13.3 Interpretation of Chromatogram—Compare the reten- or

tion times of sample components to those of the calibration w 1 3 16.0 3 N 1 w 2 3 16.0 3 N 2
analysis to determine the identities of oxygenates present. W tot 5
M1
1
M2
1. . . (22)

14. Calculations and Reporting where:

14.1 Mass Concentration of Oxygenates—After identifying wi = mass % of each oxygenate, as determined using Eq
the various oxygenates, measure the area of each oxygenate 13,
peak and that of the internal standard. From the least-squares fit Wtot = total mass % oxygen in the fuel,
calibrations, as depicted in the MTBE example in Fig. 3, Mi = molecular mass of the oxygenate, as given in Table
calculate the mass of each oxygenate (Wi) in the gasoline 1,
samples, using the response ratio (rspi) of the areas of the 16.0 = atomic mass of oxygen, and
Ni = number of oxygen atoms in the oxygenate molecule.
oxygenate to that of the internal standard as follows:

7
 D4815 − 15b
TABLE 4 Precision Interval as Determined from Cooperative Study Data
Repeatability
Component Total
MEOH EtOH iPA tBA nPA MTBE sBA DIPE iBA ETBE tAA nBA TAME
Oxygen
Wt. %
0.20 0.04 0.02 0.02 0.02 0.01 0.02 0.01 0.03 0.03 0.01 0.02 0.02 0.02
0.50 0.06 0.04 0.03 0.03 0.02 0.03 0.02 0.05 0.05 0.03 0.03 0.04 0.03
1.00 0.09 0.06 0.04 0.04 0.03 0.05 0.03 0.08 0.08 0.05 0.04 0.06 0.05 0.02
2.00 0.14 0.09 0.06 0.06 0.05 0.07 0.05 0.12 0.12 0.09 0.06 0.09 0.08 0.05
3.00 0.17 0.12 0.07 0.07 0.06 0.09 0.06 0.15 0.15 0.12 0.08 0.12 0.11 0.08
4.00 0.20 0.14 0.09 0.09 0.07 0.11 0.07 0.17 0.17 0.16 0.09 0.14 0.13 0.12
5.00 0.23 0.16 0.10 0.10 0.08 0.12 0.08 0.20 0.20 0.19 0.11 0.16 0.15 0.15
6.00 0.26 0.18 0.11 0.11 0.08 0.14 0.09 0.22 0.22 0.22 0.12 0.18 0.17
10.00 0.35 0.24 0.15 0.15 0.11 0.18 0.12 0.29 0.29 0.33 0.16 0.24 0.25
12.00 0.39 0.27 0.16 0.16 0.12 0.20 0.14 0.32 0.32 0.38 0.18 0.27 0.29
14.00 0.22 0.35 0.44 0.32
16.00 0.24 0.38 0.49 0.35
20.00 0.27 0.43 0.58 0.41
Reproducibility
Component Total
MEOH EtOH iPA tBA nPA MTBE sBA DIPE iBA ETBE tAA nBA TAME
Oxygen
Wt. %
0.20 0.14 0.09 0.14 0.07 0.04 0.04 0.15 0.14 0.14 0.11 0.06 0.09 0.14
0.50 0.24 0.16 0.26 0.12 0.07 0.08 0.28 0.26 0.26 0.21 0.10 0.15 0.22
1.00 0.37 0.23 0.42 0.19 0.11 0.12 0.44 0.42 0.42 0.46 0.15 0.22 0.31 0.09
2.00 0.57 0.34 0.67 0.30 0.16 0.19 0.70 0.67 0.67 0.61 0.22 0.33 0.44 0.22
3.00 0.72 0.43 0.80 0.40 0.21 0.25 0.92 0.88 0.88 0.83 0.28 0.41 0.54 0.36
4.00 0.86 0.51 1.06 0.48 0.24 0.30 1.11 1.06 1.06 1.03 0.33 0.49 0.63 0.52
5.00 0.99 0.58 1.23 0.56 0.28 0.35 1.29 1.23 1.23 1.22 0.38 0.55 0.70 0.70
6.00 1.10 0.64 1.40 0.63 0.31 0.40 1.46 1.40 1.40 1.41 0.42 0.61 0.77
10.00 1.51 0.86 1.97 0.89 0.41 0.56 2.06 1.97 1.97 2.07 0.56 0.82 1.00
12.00 1.68 0.95 2.22 1.00 0.45 0.63 2.33 2.22 2.22 2.38 0.62 0.91 1.10
14.00 0.70 2.46 2.68 1.19
16.00 0.77 2.69 2.96 1.28
20.00 0.89 3.13 3.51 1.43

14.6 Report the total mass % of oxygen in the fuel to the n-Butanol (nBA) 0.06 (X0.61)
nearest 0.01 mass %. TAME 0.05 (X0.70)
Total Oxygen 0.02 (X1.26)
15. Precision and Bias4 where X is the mean mass % of the component.
15.1 Precision—The precision of this test method as deter- 15.1.2 Reproducibility—The difference between two single
mined by a statistical examination of interlaboratory test results and independent results obtained by different operators work-
is as follows: ing in different laboratories on identical material would, in the
15.1.1 Repeatability—The difference between successive long run, exceed the following values in Table 4 only in one
results obtained by the same operator with the same apparatus case in twenty.
under constant operating conditions on identical test materials Reproducibility Estimates in Oxygenates in Gasolines
Component Reproducibility
would, in the long run, in the normal and the correct operation Methanol (MeOH) 0.37 (X0.61)
of the test method, exceed the following values in Table 4 only Ethanol (EtOH) 0.23 (X0.57)
in one case in twenty. Isopropanol (iPA) 0.42 (X0.67)
tert-Butanol (tBA) 0.19 (X0.67)
Repeatability Estimates for Oxygenates in Gasoline n-Propanol (nPA) 0.11 (X0.57)
Component Repeatability MTBE 0.12 (X0.67)
Methanol (MeOH) 0.09 (X0.59) sec-Butanol (sBA) 0.44 (X0.67)
Ethanol (EtOH) 0.06 (X0.61) DIPE 0.42 (X0.67)
Isopropanol (iPA) 0.04 (X0.56) Isobutanol (iBA) 0.42 (X0.67)
tert-Butanol (tBA) 0.04 (X0.56) ETBE 0.36 (X0.76)
n-Propanol (nPA) 0.003 (X0.57) tert-Pentanol (tAA) 0.15 (X0.57)
MTBE 0.05 (X0.56) n-Butanol (nBA) 0.22 (X0.57)
sec-Butanol (sBA) 0.003 (X0.61) TAME 0.31 (X0.51)
DIPE 0.08 (X0.56) Total Oxygen 0.09 (X1.27)
Isobutanol (iBA) 0.08 (X0.56)
ETBE 0.05 (X0.82) where: X is the mean mass % of the component.
tert-Pentanol (tAA) 0.04 (X0.61)
15.2 Bias—The National Institute of Standards and Tech-
nology (NIST) provides selected alcohols in reference fuels. As
4
Supporting data have been filed at ASTM International Headquarters and may an example, the following standard reference materials (SRM)
be obtained by requesting Research Report RR:D02-1296. in reference fuels are available from NIST (www.nist.gov).

8
 D4815 − 15b

Nominal Concentration, Mass % of utilized when reporting compliance with EPA fuels program.
SRM Type
MeOH EtOH MeOH + tBuOH Sample-specific bias, as defined in Practice D6708, was
1829 Alcohols in Reference Fuel 0.335 11.39 10.33 + 6.63
1837 Methanol and tert-butanol 10.33 + 6.63
observed for some samples after applying the bias-correction
1838 Ethanol 11.39 for the material types and considered random.
1839 Methanol 0.335 15.3.2 Correlation Equation:
15.3 Relative Bias—A relative bias assessment of Test Predicted Test Method D5599=
Method D4815 versus Test Method D5599 for the determina-
bias-corrected Test Method D4815 =C D481510.03 (23)
tion of ethanol in spark-ignition engine fuel was conducted
using data from the ASTM D02 Interlaboratory Crosscheck where:
Program. The assessment was performed in accordance with CD4815 = Test Method D4815 reported mass percent of
the requirements of Practice D6708 with a successful outcome. ethanol.
It was based on measurements of 82 spark-ignition engine fuels
supplied to the ASTM Proficiency Test Program by participat- 15.3.2.1 The correlation equation is only applicable for
ing laboratories between February 2007 and October 2014 and fuels in the concentration range of ethanol from 2.28 % to
is documented in Research Report RR:D02-1819.5 14.42 % by mass as reported by Test Method D4815.
15.3.2.2 The correlation equation is applicable for fuels that
NOTE 3—In the United States, the EPA requires the measurement of when determined by Test Method D5599 are in the concentra-
ethanol and other oxygenates in spark ignition engine fuels by Test tion range of range of 2.16 % to 14.39 % by mass.
Method D5599. Effective Jan. 1, 2016, there is an allowance in the
regulation to use other test methods if they are formally correlated with the NOTE 4—The Test Method D5599 concentration range used to develop
specified test method by a consensus organization, for example, ASTM. the Practice D6708 assessment may not cover the entire scope indicated in
This relative bias statement is intended to satisfy the requirement and the scope of Test Method D5599 for blended ethanol.
allow use of Test Method D4815 bias-corrected results in the stated NOTE 5—The correlation equation was developed from a variety of fuel
concentration ranges in place of Test Method D5599 for ethanol content. samples from the ASTM Interlaboratory Crosscheck programs; however,
15.3.1 The degree of agreement between results from Test it is recommended that the correlation equation be verified for samples of
interest to ensure applicability.
Method D4815 and Test Method D5599 can be further im-
proved by applying a correlation equation (Eq 23) (Research
16. Keywords
Report RR:D02-1819),5 and this correlation equation shall be
16.1 alcohols; DIPE (disopropylether) ; ETBE (ethyl tert-
5
butylether); ethers; gas chromatography; gasoline; MTBE
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR:D02-1819. Contact ASTM Customer (methyl tert-butylether); oxygenates; TAME (tert-
Service at service@astm.org. amylmethylether)

ANNEX

(Mandatory Information)

A1. HYDROCARBON INTERFERENCE

A1.1 Fig. A1.1 shows the interference from hydrocarbons gasoline, and the resulting chromatogram was compared with
for a gasoline containing 10 volume % olefins. Each alcohol that obtained with no ethers or alcohols added.
and ether was added at 0.1 mass % into the 10 volume % olefin

9
 D4815 − 15b

FIG. A1.1 Chromatogram Showing Hydrocarbon Interference

APPENDIX

(Nonmandatory Information)

X1. NITROGEN CARRIER GAS

NOTE X1.1—This appendix contains instrument conditions and results is much easier to obtain at lower cost. This appendix contains instrument
obtained using nitrogen as an alternative carrier gas. At this time, because conditions and results obtained using nitrogen carrier gas for the analysis
the test method precision and bias performance information using the of ethanol and MtBE in pump gasoline samples.
alternative carrier gases and conditions listed in this appendix have not
been studied in accordance with the proper ASTM ILS process, this X1.1 This section lists the GC operating conditions for
appendix is included only for information purposes. Results obtained
under the conditions described in this appendix are not considered to be D4815 utilizing nitrogen carrier gas. These conditions are same
valid D4815 results, and shall not be represented as such. as those for helium carrier gas described in Table 2. The back
NOTE X1.2—Helium is a widely used carrier gas for most capillary gas flush time and valve reset time shown in Table X1.1 were
chromatographic applications. Recent disruptions in helium supplies experimentally determined for the GC system used in this
combined with higher prices have prompted the search for alternative
carrier gases where helium’s chromatographic properties are not critical to study. These values will vary from system to system depending
the method’s performance. Nitrogen is a suitable helium replacement and on differences found in the columns.

10
 D4815 − 15b
TABLE X1.1 GC Conditions Utilizing Nitrogen Carrier Gas
Carrier gas Nitrogen (99.9995 %)
Inlet Split/splitless
Inlet temperature 200 °C
Inlet flow 75 mL/min
Split ration 15:1
Column flow 5 mL/min
Auxiliary flow 3 mL/min
Valve temperature 60 °C
Oven temperature 60 °C
Detector Flame ionization
Detector temperature 250 °C
Back flush time 0.24 min
Valve reset time 14 min
Total analysis time 16 min

FIG. X1.1 Analysis of Ethanol in Gasoline Utilizing Nitrogen Carrier Gas Conditions Described in Table X1.1

FIG. X1.2 Analysis of MtBE in Gasoline Utilizing the Nitrogen Carrier Gas Conditions Described in Table X1.1

11
 D4815 − 15b
TABLE X1.2 Analysis of Four Gasoline Samples using D4815 and
Nitrogen Carrier Gas
NOTE 1—Observed repeatability (r) was determined from replicate
analysis of each sample.
Compound Mass % Observed r D4815r
Ethanol 0.99 0.01 0.06
Ethanol 6.63 0.03 0.19
MtBE 2.10 0.01 0.08
MtBE 11.29 0.05 0.19

SUMMARY OF CHANGES

Subcommittee D02.04.0L has identified the location of selected changes to this standard since the last issue
(D4815 – 15a) that may impact the use of this standard. (Approved Dec. 1, 2015.)

(1) Added new subsections 1.3 and 15.3.

Subcommittee D02.04.0L has identified the location of selected changes to this standard since the last issue
(D4815 – 15) that may impact the use of this standard. (Approved April 1, 2015.)

(1) Added new Note X1.2.

Subcommittee D02.04.0L has identified the location of selected changes to this standard since the last issue
(D4815 – 13) that may impact the use of this standard. (Approved Feb. 1, 2015.)

(1) Added new Appendix X1.

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12