ASTM D7057-23

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Designation: D7057 − 18 D7057 − 23
Standard Test Method for
Analysis of Isopropylbenzene (Cumene) by Gas
Chromatography (External Standard)
This standard is issued under the fixed designation D7057; 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 of the purity of isopropylbenzene (cumene) by gas chromatography. Calibration of
the gas chromatography system is done by the external standard calibration technique.
1.2 This test method has been found applicable to the measurement of impurities such as nonaromatic hydrocarbons, benzene,
toluene, ethylbenzene, phenol, cymenes, t-butylbenzene, n-butylbenzene, n-propylbenzene, alpha-methylstyrene, sec-
butylbenzene, and diisopropylbenzenes, which are impurities that can be found in isopropylbenzene. The latter impurities can be
analyzed over a range of 1 mg/kg to 500 mg/kg by this method (see Table 1). The limit of quantitation averages 3.8 mg/kg while
the limit of detection for these impurities averages 1.1 mg/kg.mg/kg based on the data in Table 1.
1.3 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded off
in accordance with the rounding-off method of Practice E29.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. For specific hazard statements, see Section 89.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
D3437 Practice for Sampling and Handling Liquid Cyclic Products
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D4790 Terminology of Aromatic Hydrocarbons and Related Chemicals
D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E355 Practice for Gas Chromatography Terms and Relationships
This test method is under the jurisdiction of ASTM Committee D16 on Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsibility of
Subcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic Hydrocarbons.
Current edition approved Jan. 1, 2018April 1, 2023. Published January 2018April 2023. Originally approved in 2004. Last previous edition approved in 20132018 as D7057
– 13. DOI: 10.1520/D7057-18.18. DOI: 10.1520/D7057-23.
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.
*A Summary of Changes section appears at the end of this standard
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D7057 − 23
TABLE 1 Summary of Precision Data (mg/kg)
Range
Compound Repeatability Reproducibility
Studied
Benzene 1.004+0.006*Benzene 0.924+0.158*Benzene 1.0–295
Toluene 0.644+0.009*Toluene 1.505+0.069*Toluene 0.2–260
Ethylbenzene (EB) 1.249+0.022*EB 2.534+0.230*EB 5–370
n-Propylbenzene (NPB) -0.369+0.015*NPB -6.793+0.214*NPB 180–465
Phenol (PHE) 1.926+.0095*PHE 3.718+0.207*PHE 1–225
alpha-methylstyrene(AMS) 1.368+0.057*AMS 21.181+0.976*AMS 6–305
tert-Butylbenzene(TBB) 1.666+0.011*TBB 4.126+0.086*TBB 2–250
sec-Butylbenzene(SBB) 0.635+0.010*SBB 0.891+0.090*SBB 2–245
m-Cymene 0.618+0.011*m-Cymene 1.811+0.181*m-Cymene 5–240
o-Cymene 0.498+0.012*o-Cymene 1.951+0.156*o-Cymene 1–160
p-Cymene 0.485+0.019*p-Cymene 1.618+0.097*p-Cymene 2–270
n-Butylbenzene(NBB) 0.445+0.030*NBB 2.600+0.045*NBB 0.3–265
1,3-diisopropylbenzene(13DIPB) 0.727+0.010*13DIPB 1.570+0.720*13DIPB 1–210
1,4-diisopropylbenzene(14DIPB) 0.435+0.013*14DIPB 1.112+0.040*14DIPB 1–285
NonAromatics(NA) 0.441+0.242*NA 1.663+0.306*NA 5–95
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs
2.2 Other Document:
OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200
3. Terminology
3.1 See Terminology D4790 for definition of terms used in this test method.
4. Summary of Test Method
4.1 Cumene (isopropylbenzene) is analyzed by a gas chromatograph (GC) equipped with a flame ionization detector (FID). A
precisely repeatable volume of the sample to be analyzed is injected onto the gas chromatograph. The peak areas of the impurities
are measured and converted to concentrations via an external standard methodology. Purity by GC (the Cumene content) is
calculated by subtracting the sum of the impurities from 100.00, excluding Acetophenone (AP) and 2-phenyl-2-propanol (DMPC
or DMBA) which are artifacts of cumene hydroperoxide (CHP) thermal decomposition in the inlet of the GC. Results are reported
in weightmass percent.
5. Significance and Use
5.1 This test method is suitable for setting specifications on the materials referenced in 1.2 and for use as an internal quality control
tool where isopropylbenzene is produced or is used in a manufacturing process. It may also be used in development or research
work involving isopropylbenzene.
5.2 This test method is useful in determining the purity of isopropylbenzene with normal impurities present. If extremely high
boiling or unusual impurities are present in the isopropylbenzene, this test method would not necessarily detect them and the purity
calculation would be erroneous.
5.3 Cumene hydroperoxide, if present, will yield thermal decomposition products, primarily AP and DMPC as stated in 4.1, that
will elute in the chromatogram thereby giving incorrect results unless they are excluded as indicated in 4.1. It is also possible to
get erroneous results for trace alpha-methylstyrene present in isopropylbenzene if the inlet has become unduly contaminated with
non-volatile foreign substances.
5.4 The nonaromatic hydrocarbons commonly present from the isopropylbenzene manufacturing process, particularly a
non-zeolitic one, will interfere with the determination of xylenes (if present).
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D7057 − 23
6. Apparatus
6.1 Gas Chromatograph—Any instrument having a flame ionization detector that can be operated at the conditions given in Table
2. The system should have sufficient sensitivity to obtain a minimum peak height response for 1 mg/kg benzene of twice the height
of the signal background noise.
6.2 Columns—The choice of column is based on resolution requirements. Any column may be used that is capable of resolving
all significant impurities from isopropylbenzene. The column described in Table 2 has been used successfully and shall be used
as a referee in cases of dispute. Unless the analyst can be sure of peak identity, for example by gas chromatography-mass
spectrometry (GC-MS), the use of the column in Table 2 is strongly recommended.
6.3 Recorder—Chromatographic data systems are preferred but electronic integration may be used if the user can demonstrate that
the results are consistent with the precision statement. Recorders are not considered adequate for meeting the precision
requirements of this standard.
6.4 Injector—The specimen must be precisely and repeatedly injected into the gas chromatograph. An automatic sample injection
device is highly recommended. Manual injection can be employed if the precision stated in Table 1, Summary of Precision Data,
can be reliably and consistently satisfied.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
7.2 Carrier Gas, Makeup, and Detector Gases—Helium, hydrogen, nitrogen, or other carrier, makeup and detector gases 99.999 %
minimum purity. Oxygen in carrier gas less than 1 ppm, less than 0.5 ppm is preferred. Purify carrier, makeup, and detector gases
to remove oxygen, water, and hydrocarbons.
TABLE 2 Recommended Operating Conditions
Detector flame ionization
Injection Port capillary splitter
Column A:
Tubing fused silica
Stationary Phase crosslinked
polydimethylsilicone (HP-1,
DB-1 or equiv)
Film Thickness, μm 1.0
Length, m 60
Diameter, mm 0.32
Temperatures:
Injector, °C 250
Detector, °C 300
Oven, °C 85 hold for 13 min
Ramp 1 = 6°C/min to
125°C, hold for 2 min
Ramp 1 = 6 °C ⁄min to
125 °C, hold for 2 min
Ramp 2 = 30°C/min to
250°C, hold for 7.5 min
Ramp 2 = 30 °C ⁄min to
250 °C, hold for 7.5 min
Carrier Gas Helium
Flow Rate, mls/min 3
Split Ratio 60:1
Sample Size, μL 1.0
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the tes
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