ASTM D5769-22

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D5769 − 20 D5769 − 22
Standard Test Method for
Determination of Benzene, Toluene, and Total Aromatics in
Finished Gasolines by Gas Chromatography/Mass
Spectrometry
This standard is issued under the fixed designation D5769; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination in volume percent of benzene, toluene, other specified individual aromatic
compounds, and total aromatics in finished motor gasoline, including gasolines containing oxygenated blending components, by
gas chromatography/mass spectrometry (GC/MS). Precision is calculated for benzene, toluene and total aromatics.
1.2 This test method has been tested for evaluated using a D6300the following concentration ranges, in liquid volume percent, for
the following aromatics: benzene, 0.1 % to 4 %; toluene, 1 % to 13 %;-compliant Interlaboratory Study (ILS), with the lowest and
highest ILS sample averages listed as follows: benzene, 0.09 % to 4.00 %; toluene, 1.0 % to 13.0 %; and total (C6 to C12)
aromatics, 10 %10.0 % to 42 %.42.0 %. The round-robinILS study did not test the method for individual hydrocarbon process
streams produced in a refinery, such as reformates, fluid catalytic cracked naphthas, and so forth, used in the blending of gasolines.
1.3 Results are reported to the nearest 0.01 % for benzene and 0.1 % for the other aromatics by liquid volume. The Report Section
(14) describes the applicable reporting ranges of this test method.
1.4 This test method includes a relative between test method bias section for EPA spark-ignition engine fuel benzene regulations
reporting based on Practice D6708 accuracy assessment between Test Method D5769 and Test Method D3606 as a possible Test
Method D5769 alternative to Test Method D3606. The Practice D6708 derived correlation equation is only applicable for blended
fuels in the with benzene results concentration range from 0.00.05 % to 2.50 % by volume as measured and reported by Test
Method D5769. The applicable Test Method D3606 range for benzene is from 0.0 % to 2.47 % by volume as reported by Test
Method D3606.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to its use.
1.7 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.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0M on Mass Spectrometry.
Current edition approved June 1, 2020July 1, 2022. Published June 2020August 2022. Originally approved in 1995. Last previous edition approved in 20152020 as
D5769 – 15.D5769 – 20. DOI: 10.1520/D5769-20.10.1520/D5769-22.
*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
D5769 − 22
2. Referenced Documents
2.1 ASTM Standards:
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by
Hydrometer Method
D3606 Test Method for Determination of Benzene and Toluene in Spark Ignition Fuels by Gas Chromatography
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
E355 Practice for Gas Chromatography Terms and Relationships
3. Terminology
3.1 This test method makes reference to common terms, procedures, and relationships. Detailed definitions of these may be found
in Practice E355 and Terminology D4175.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 aromatic, n—any hydrocarbon compound containing a benzene or naphthalene ring.
3.2.2 calibrated aromatic component, n—the individual aromatic components that have a specific calibration.
3.2.3 cool on-column injector, n—in gas chromatography, a direct sample introduction system that is set at a temperature at or
below the boiling point of solutes or solvent on injection and then heated at a rate equal to or greater than the column. Normally
used to eliminate boiling point discrimination on injection or to reduce adsorption on glass liners within injectors, or both. The
sample is injected directly into the head of the capillary column tubing.
3.2.4 open split interface, n—GC/MS interface used to maintain atmospheric pressure at capillary column outlet and to eliminate
mass spectrometer vacuum effects on the capillary column. Can be used to dilute the sample entering the mass spectrometer to
maintain response linearity.
3.2.5 reconstructed ion chromatogram (RIC), n—a limited mass chromatogram representing the intensities of ion mass
spectrometric currents for only those ions having particular mass to charge ratios. Used in this test method to selectively extract
or identify aromatic components in the presence of a complex hydrocarbon matrix, such as gasoline.
3.2.6 retention gap, n—in gas chromatography, refers to a deactivated precolumn which acts as a zone of low retention power for
reconcentrating bands in space. The polarity of the precolumn must be similar to that of the analytical column.
3.2.7 split ratio, n—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:
split ratio 5 S1C /C (1)
~ !
where:
S = flow rate at the splitter vent, and
C = flow rate at the column outlet.
3.2.8 total ion chromatogram (TIC), n—mass spectrometer computer output representing either the summed intensities of all
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D5769 − 22
scanned ion currents or a sample of the current in the ion beam for each spectrum scan plotted against the corresponding spectrum
number. Generally, it can be correlated with a flame ionization detector chromatogram.
3.2.9 uncalibrated aromatic component, n—individual aromatics for which a calibration is not available. These components are
estimated from the calibration of several calibrated aromatic components.
3.2.10 wall coated open tubular (WCOT), n—a type of capillary column prepared by coating or bonding the inside wall of the
capillary with a thin film of stationary phase.
4. Summary of Test Method
4.1 A gas chromatograph equipped with a dimethylpolysiloxane WCOT column is interfaced to a fast scanning mass spectrometer
that is suitable for capillary column GC/MS analyses. The sample is injected either through a capillary splitter port or a
cool-on-column injector capable of introducing a small sample size without overloading the column. The capillary column is
interfaced directly to the mass spectrometer or by way of an open split interface or other appropriate device.
4.2 Calibration is performed on a mass basis, using mixtures of specified pure aromatic hydrocarbons. Volume percent data is
calculated from the densities of the individual components and the density of the sample. A multipoint calibration consisting of
at least five levels and bracketing the expected concentrations of the specified individual aromatics is required. Specified deuterated
hydrocarbons are used as the internal standards, for example, d6-benzene for quantitating benzene. Unidentified aromatic
hydrocarbons present that have not been specifically calibrated for are quantitated using the calibration of an adjacent calibrated
compound and summed with the other aromatic components to obtain a total aromatic concentration of the sample.
4.3 Specified quality control mixture(s), such as synthetic quality control mixtures must be analyzed to monitor the performance
of the calibrated GC/MS system. Analysis of a gasoline as a reference material is strongly recommended.
5. Significance and Use
5.1 Test methods to determine benzene and the aromatic content of gasoline are necessary to assess product quality and to meet
fuel regulations.
5.2 This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined
that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this
test method.
6. Apparatus
6.1 Gas Chromatography:
6.1.1 System equipped with temperature-programmable gas chromatograph suitable for split injections with WCOT column or
cool-on-column injector that allows the injection of small (for example, 0.1 μL) samples at the head of the WCOT column or a
retention gap. An autosampler is mandatory for the on-column injections.
6.1.2 WCOT column containing dimethylpolysiloxane bonded stationary phase, meeting the specification in the following table.
For on-column injections, a column containing a thicker film of stationary phase, such as 4 μm to 5 μm, is recommended to prevent
column sample overload.
Resolution R between 1,3,5-
2 t12t2
s d
trimethylbenzene and 1-methyl-2-
R 5
1.699sy21y1d
ethylbenzene at the 3 % by mass level
each must be equal to or greater than t2 = retention time of 1,3,5-
2.0
trimethylbenzene
t1 = retention time of
1-methyl-2-ethylbenzene
y2 = peak width at half height
of 1,3,5-trimethylbenzene
y1 = peak width at half height
1-methyl-2-ethyl benzene
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6.2 Mass Spectrometry:
6.2.1 Mass spectrometer capable of producing electron impact spectra at 70, or higher, electron volts or equivalent, and capable
of scanning the range of the specified quantitation masses or m/e. The mass scan range shall cover the masses of interest for
quantitation and should yield at least 5 scans across the peak width at half peak width for a 1 % to 3 % by mass toluene and cover
the masses of interest for quantitation. A scan range of 41 to 200 daltons is adequate.
6.2.2 The mass spectrometer must be capable of being interfaced to a gas chromatograph and WCOT columns. The interface must
be at a high enough temperature to prevent condensation of components boiling up to 220 °C, usually 20 °C above the final column
temperature is adequate. Direct column interface to the mass spectrometer can be used. An open split interface with computer
controlled programmable flow controller(s) can also be used, particularly with cool on-column injections, to maintain all aromatic
components within the linearity of the mass spectrometer and at the same time maintain detectability of lower concentration
aromatic components. For example, a higher open-split-interface make-up gas flow can be used for the high concentration
components, such as toluene and xylenes, and a lower make-up gas flow rate may be used during the elution of the lower
concentration benzene and C9+ components. Other interfaces may be used provided the criteria specified in Sections 9 and 10 are
met.
6.2.3 A computer system shall be interfaced to the mass spectrometer to allow acquisition of continuous mass scans or total ion
chromatogram (TIC) for the duration of the chromatographic program and be able to analyze repeatedly 0.01 % by mass
1,4-diethylbenzene with the specified signal/noise ratio of 5. Software must be available to allow searching any GC/MS run for
specific ions or reconstructed ions and plotting the intensity of the ions with respect to time or scan number. The ability to integrate
the area under a specific ion plot peak is essential for quantitation. The quantitation software must allow linear least squares or
quadratic nonlinear regression and quantitation with multiple internal standards. It is also recommended that software be available
to automatically perform the identification of aromatic components as specified in 13.1.1.
7. Reagents and Materials
7.1 Carrier Gas—Helium and hydrogen have been used successfully. The recommended minimum purity of the carrier gas used
is 99.999 mol percent. Additional purification using commercially available scrubbing reagents may be necessary to remove trace
oxygen, which may deteriorate the performance of the GC WCOT. (Warning—Helium and hydrogen are supplied under high
pressure. Hydrogen can be explosive and requires special handling. Hydrogen monitors that automatically shut off supply to the
GC in case of serious leaks are available from GC supply manufacturers.)
7.2 Dilution Solvents—Reagent grade 2,2,4-trimethylpentane (iso-octane), n-heptane, n-nonane, cyclohexane, or toluene, or a
combination thereof, used as a solvent in the preparation of the calibration mixtures. (Warning—The gasoline samples and
solvents used as reagents such as iso-octane, cyclohexane, n-heptane, n-octane, and toluene, are flammable and may be harmful
or fatal if ingested or inhaled. Benzene is a known carcinogen. Use with proper ventilation. Safety glasses and gloves are required
while preparing samples and standards. Samples should be kept in well ventilated laboratory areas.)
NOTE 1—Toluene should be used as a solvent only for the preparation of C9+ components and shall be free from interfering aromatics.
7.3 Internal Standards—Deuterated analogs of benzene, ethylbenzene, and naphthalene, as specified in Table 1, shall be used as
internal standards because of their similar chromatographic characteristics as the components analyzed. The use of a fourth internal
standard toluene-d8 is recommended. Deuterated naphthalene is hygroscopic and should be stored away from high humidity.
7.4 Standards for Calibration and Identification—Aromatic hydrocarbons used to prepare standards should be 99 % or greater
purity (see Table 1). If reagents of high purity are not available, an accurate assay of the reagent shall be performed using a properly
calibrated GC or other techniques. The concentration of the impurities that overlap the other calibration components shall be
known and used to correct the concentration of the calibration components. The use of only high purity reagents is strongly
recommended because of the error that may be introduced from impurity corrections. Standards are used for calibration as well
as for establishing the identification by retention time in conjunction with mass spectral match (see 13.1.1). Naphthalene is
hygroscopic and should be stored away from high humidity.
8. Sampling
8.1 Every effort should be made to ensure that the sample is representative of the fuel source from which it is taken. Follow the
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TABLE 1 Mass Spectrometer Quantitation Ions for Sample Components and Internal Standards
Compound CAS Primary Ion Internal Standard ISTD ION
No. (Dalton) (ISTD) (Dalton)
Benzene 71-43-2 78 Benzene-d6 84 + 83
Toluene 108-88-3 92 Ethylbenzene-d10 or 116 + 115 or 100 + 99
toluene-d8
Ethylbenzene 100-41-4 106 Ethylbenzene-d10 116 + 115
1,3-Dimethylbenzene 108-38-3 106 Ethylbenzene-d10 116 + 115
1,4-Dimethylbenzene 106-42-3 106 Ethylbenzene-d10 116 + 115
1,2-Dimethylbenzene 95-47-6 106 Ethylbenzene-d10 116 + 115
(1-Methylethyl)-benzene 98-82-8 120 Ethylbenzene-d10 116 + 115
Propyl-benzene 103-65-1 120 Ethylbenzene-d10 116 + 115
1-Methyl-3-ethylbenzene 620-14-4 120 Ethylbenzene-d10 116 + 115
1-Methyl-4-ethylbenzene 622-96-8 120 Ethylbenzene-d10 116 + 115
1,3,5-Trimethylbenzene 108-67-8 120 Ethylbenzene-d10 116 + 115
1-Methyl-2-ethylbenzene 611-14-3 120 Ethylbenzene-d10 116 + 115
1,2,4-Trimethylbenzene 95-63-6 120 Ethylbenzene-d10 116 + 115
1,2,3-Trimethylbenzene 526-73-8 120 Ethylbenzene-d10 116 + 115
Indan 496-11-7 117 Ethylbenzene-d10 116 + 115
1,4-Diethylbenzene 105-05-5 134 Naphthalene-d8 136 + 135
n-Butylbenzene 104-51-8 134 Naphthalene-d8 136 + 135
1,2-Diethylbenzene 135-01-3 134 Naphthalene-d8 136 + 135
1,2,4,5-Tetramethylbenzene 95-93-2 134 Naphthalene-d8 136 + 135
1,2,3,5-Tetramethylbenzene 527-53-7 134 Naphthalene-d8 136 + 135
Naphthalene 91-20-3 128 Naphthalene-d8 136 + 135
2-Methyl-naphthalene 91-57-6 142 Naphthalene-d8 136 + 135
1-Methyl-naphthalene 90-12-0 142 Naphthalene-d8 136 + 135
recommendations of Practice D4057, or its equivalent, when obtaining samples from bulk storage or pipelines. Sampling to meet
certain regulatory specifications may require the use of specific sampling procedures. Consult appropriate regulations.
8.2 Appropriate steps should be taken to minimize the loss of light hydrocarbons from the gasoline sample while sampling and
during analyses. Upon receipt in the laboratory, chill the sample in its original container to between 0 °C to 5 °C before and after
a sample aliquot is removed for analysis.
8.3 After the sample is prepared for analysis with internal standard(s), chill the sample and fill the autosampler vial to
approximately 90 % of its volume. The remainder of the sample should be re-chilled immediately and protected from evaporation
for further analyses, if necessary. To prevent evaporation of the sample, the autosampler vials should be stored at 0 °C to 5 °C until
ready for loading on the autosampler.
9. Calibration
9.1 Preparation of Calibration Standards—Multi-component calibration standards using all the compounds listed in Table 1 are
prepared by mass according to Practice D4307. The standards may be prepared by combining the specified individual aromatics
either into a single mixture or into multiple sets. Multiple sets may be prepared as follows: (1) Set I consists of benzene,
methylbenzene (toluene), ethylbenzene, 1,2-dimethylbenzene, 1,3-dimethylbenzene, and 1,4-dimethylbenzene, using 2,2,4-
trimethylpentane (isooctane) as a recommended dilution solvent; (2) Set II consists of the remaining C + components using a 50/50
mixture of 2,2,4-trimethylpentane and methylbenzene (toluene) as the recommended dilution solvent. Other solvents, such as
n-nonane, or co-solvents may be used to improve solubility, chromatographic or mass spectrometric performance, provided these
solvents contain no detectable amounts of aromatics which will interfere with the analyses.
NOTE 2—It may be more convenient to prepare gravimetrically pure (solvent free) batches of Set I and Set II components, which then can be weighed
into appropriate diluted standards. The internal standards for Set I are benzene-d and ethylbenzene-d . Toluene-d may be added to the internal standard
6 10 8
mixture for the quantitation of toluene. The internal standards for Set II are ethylbenzene-d and naphthalene-d .
10 8
NOTE 3—Appropriate internal standards batches may be prepared and then added to calibration standards and samples in a single step.
A minimum of five calibration solutions shall be prepared by mass for single mixtures containing all of the specified calibration
compounds. For toluene, three of the calibration standards must be above the 50 % point of the calibration range. If nonlinearity
is observed, the addition of a sixth calibration standard is recommended to better define its potential nonlinearity at the higher
concentration range. If the calibration solutions are prepared in sets, then for each set, five separate solutions must be prepared over
the desired concentration range; for example, five calibration solutions for Set I, and five calibration solutions for Set II. Table 2
gives the recommended volumes to be weighed into 100 mL volumetric flasks or 100 mL septum capped vials for the most
concentrated calibration standard. Adjust these concentrations, as necessary, to ensure that the concentrations of the components
D5769 − 22
TABLE 2 Relative Densities and Calibration Concentrations
Compound Relative Target Highest Calibration Components Calibration Components
Density Concentration Calibration Prepared into Prepared into
60 °F ⁄60 °F Solution (volume % a Single Mixture Two Sets of Mixtures
or mL/100 mL)
Compound Relative Target Highest Calibration Components Calibration Components
Density Concentration Calibration Prepared into Prepared into
60 °F ⁄60 °F Solution (volume percent a Single Mixture Two Sets of Mixtures
or mL/100 mL)
Benzene 0.8845 5 Set 1 Set 1
Toluene 0.8719 19 Set 1 Set 1
Ethylbenzene 0.8718 5 Set 1 Set 1
1,3-Dimethylbenzene 0.8688 6 Set 1 Set 1
1,4-Dimethylbenzene 0.8657 6 Set 1 Set 1
1,2-Dimethylbenzene 0.8846 6 Set 1 Set 1
(1-Methylethyl)-benzene 0.8664 3 Set 1 Set 2
Propyl-benzene 0.8665 3 Set 1 Set 2
1-Methyl-3-ethylbenzene 0.8691 3 Set 1 Set 2
1-Methyl-4-ethylbenzene 0.8657 3 Set 1 Set 2
1,3,5-Trimethylbenzene 0.8696 3 Set 1 Set 2
1-Methyl-2-ethylbenzene 0.8851 3 Set 1 Set 2
1,2,4-Trimethylbenzene 0.8803 5 Set 1 Set 2
1,2,3-Trimethylbenzene 0.8987 3 Set 1 Set 2
Indan 0.9689 3 Set 1 Set 2
1,4-Diethylbenzene 0.8664 3 Set 1 Set 2
n-Butylbenzene 0.8646 3 Set 1 Set 2
1,2-Diethylbenzene 0.8843 3 Set 1 Set 2
1,2,4,5-Tetramethylbenzene 0.8915 3 Set 1 Set 2
1,2,3,5-Tetramethylbenzene 0.8946 2 Set 1 Set 2
A
Naphthalene 1.000 2 Set 1 Set 2
A
2-Methyl-naphthalene 1.000 2 Set 1 Set 2
1-Methyl-naphthalene 1.0245 2 Set 1 Set 2
Uncalibrated indans 1.000 —
Uncalibrated C10-benzenes 0.878 — —
Uncalibrated C11 benzenes 1.000 — —
Uncalibrated C12-benzenes 1.000 — —
A
These components are solids at ambient temperature. The values represent g/100 mL
in the actual samples are bracketed by the calibration concentrations. Solid components are weighed directly into the flask or vial.
Other more dilute standards are prepared separately by weighing appropriate amounts of the pure aromatic components. Prepare
a calibration standard according to Practice D4307 as follows:
9.1.1 Cap and record the tare weight of the 100 mL volumetric flask or vial to 0.1 mg.
9.1.2 Remove the cap and carefully add an aromatic component to the flask or vial starting with the least volatile component. Cap
the flask and record the net mass (Wi) of the aromatic component added to 0.1 mg.
9.1.3 Repeat the addition and weighing procedure for each aromatic component.
9.1.4 If Sets I and II components were pre-mixed gravimetrically, then to each calibration solution, volumetric flask, or vial, weigh
appropriate volumes to yield the ten calibration solutions. Calculate the actual mass of each component by multiplying the total
mass of the combined mixture by the mass fraction of the individual components in the pre-mixed undiluted mixture.
9.1.5 Similarly add each internal standard and record its net mass (Ws) to 0.1 mg. If standards are prepared in multiple sets; for
Set I weigh 2 mL each of benzene-d6 and ethylbenzene-d10, and for Set II weigh 2 mL of ethylbenzene-d10 and 1 g
naphthalene-d8.
9.1.6 Dilute to 100 mL total volume the standard with the recommended solvents above or equivalent. It is not necessary to weigh
the amount of solvent added since the calculations are based on the absolute masses of the aromatic and internal standard
components.
9.1.7 Similarly prepare four additional standards to cover the concentration range of interest. For example, for benzene, prepare
0.1, 0.5, 1.0, 3.0, and 5.0 targeted volume percent standards; for toluene, prepare 2.0, 5.0, 10.0, 15.0, and 19.0 targeted volume
percent equivalent standards. If the calibration response for toluene is nonlinear, then add a sixth calibration standard, such as 2.0,
5.0, 10.0, 15.0, 17.0, and 19.0 targeted volume percent.
D5769 − 22
9.1.8 Store the capped calibration standards in a refrigerator at 0 °C to 5 °C when not in use.
9.1.9 Thoroughly mix the prepared standards using a vortex mixer, or equivalent, and transfer approximately 2 mL of the solution
to a vial compatible with the autosampler if such equipment is used. Chill the vials until ready for loading on the autosampler.
NOTE 4—Highly precise robotic or semi-automated sample preparation systems are available commercially. These systems may be used to prepare mass
percent calibration standards and samples for analyses provided that the results for the quality control reference material (Section 10) are met when
prepared with the automated systems.
9.2 GC/MS Calibration Procedure:
9.2.1 Prepare the GC/MS system according to manufacturer’s instructions and set analysis operating conditions. Table 3 gives
suggested operating conditions for split and on-column injection modes.
A
TABLE 3 Examples of GC/MS Conditions
Condition 1 Condition 2 Condition 3
Gas
Chromatography
(GC):
Column 60 m × 0.25 60 m × 0.32 20 m × 0.18 mm
mm mm
df=1.0 um i.d., df=5.0 um i.d., df=0.4 um
dimethyl dimethyl dimethyl
polysiloxane polysiloxane polysiloxane
Injector type splitter cool on-column splitter
Injector split ratio 250:1 — approximately
700:1
Injection size (ul) 0.1–0.5 0.1 0.1 ul
Injector temperature (C) 250 °C track oven 250 °C
temperature
Oven temperature 60 °C (0 min), 50 °C (0 min), 35 °C (1 min),
3 °C ⁄min to 2 °C ⁄min to 25 °C ⁄min to
120 (0 min) 190 °C (0 min); 210 °C (1 min)
10 °C ⁄min to 30 °C ⁄min to
250 °C. 300 °C (1 min).
Carrier gas helium hydrogen helium
Carrier gas linear velocity 35 at 50 °C 42 at 300 °C 30 cm/s at 50 °C
(cm/s)
GC/MS Interface:
GC/MS interface type direct open-split with direct
variable flow
Interface temperature (C) 280 280 250
Mass Spectrometry (MS):
MS Type quadrupole quadrupole quadrupole
B B B
MS data acquisition mode full scan full scan full scan
Scan Rate (scan/s) >1 >1 10
Source temperature (C) approximately approximately approximately
250 250 250
B B B
Ionization voltage (eV) 70 70 70
Mass scan range 45–300 45–200 70–170
A
The above are approximate conditions reported by several laboratories. Other
conditions that meet the specifications in the method may be used also.
B
Fixed operating conditions; must be used as indicated.
D5769 − 22
9.2.2 Before initiating the calibration procedure, tune the mass spectrometer according to manufacturer’s instructions. Set the mass
spectrometer data system to acquire data in the full scan (TIC-RIC) mode.
9.2.3 The WCOT shall meet the resolution requirements described in 6.1.2 when installed in the GC/MS system.
9.2.4 Prepare a solution of 0.01 % by mass of 1,4-diethylbenzene and verify that it is detected with a signal/noise ratio of at least
5 at mass 134.
9.2.5 Inject a solution of 3 % by mass of 1,2,3-trimethylbenzene and confirm that the mass spectrometer provides a fragmentation
pattern as specified in Table 4.
9.2.6 Sequentially analyze the calibration standards.
9.3 Calibration Calculations:
9.3.1 After the analyses of the calibration standards are complete, integrate the peak area of each calibration component and
internal standards using the reconstructed ion chromatogram (RIC) of the characteristic calibration ion listed in Table 1. Obtain
the area under the extracted ion at the retention time of the expected aromatic component (or internal standard).
9.3.1.1 Erroneous aromatic concentrations may result when the deuterated internal standards used for calibrations are from a
different batch or lot used for the samples. The most accurate results are obtained when using the same batch of internal standards
for the calibration and the sample. However, if the ratio of the intensities of (M-1)/M for the internal standards in the calibration
standards divided by the ratio of the intensities of (M-1)/M of the corresponding internal standards in the sample being analyzed
is less
...