ASTM D6142-21

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Designation: D6142 − 16 D6142 − 21
Standard Test Method for
Analysis of Phenol by Capillary Gas Chromatography
This standard is issued under the fixed designation D6142; 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 known impurities in phenol by gas chromatography (GC). It is generally meant
for the analysis of phenol of 99.9 % or greater purity.
1.2 This test method has been found applicable over impurity concentrations of 15 up to 70 mg/kg. Users of this method believe
it is linear over a wider range. The limit of detection (LOD) is 1.7 mg/kg and the limit of quantitation (LOQ) is 5.8 mg ⁄kg.
NOTE 1—LOD is defined in 7.1 as part of the method setup. The values above were calculated based on the ILS data for acetone, acetophenone,
α-methylstyrene, and 2-methylbenzofuran in Table 3.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.
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:
D3852 Practice for Sampling and Handling Phenol, Cresols, and Cresylic Acid
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
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the direct
responsibility of Subcommittee D16.02 on Oxygenated Aromatics.
Current edition approved June 1, 2016Nov. 1, 2021. Published June 2016November 2021. Originally approved in 1997. Last previous edition approved in 20122016 as
D6142D6142 – 16. – 12. DOI: 10.1520/D6142-16.10.1520/D6142-21.
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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D6142 − 21
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 definitiondefinitions of terms used in this test method.
4. Summary of Test Method
4.1 A known amount of an internal standard is added to a sample of phenol. The prepared sample is mixed and analyzed by a gas
chromatograph equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standard is
measured. The amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak area
of the impurity. Results are reported in milligrams per kilogram.
5. Significance and Use
5.1 This test method is suitable for setting specifications on phenol and for use as an internal quality control tool where phenol
is produced or is used in a manufacturing process. It may also be used in development or research work involving phenol. It is
generally applied to determining those commonly occurring impurities such as mesityl oxide, cumene, hydroxyacetone, acetone,
alpha-methylstyrene,α-methylstyrene, 2-methylbenzofuran, and acetophenone.
5.2 Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromatographic
analysis cannot determine absolute purity if water is present or unknown components are contained within the material being
examined.
6. Interferences
6.1 The internal standard chosen must be sufficiently resolved from any impurity and the phenol peak.
6.2 Any solvent used must also be sufficiently resolved from any impurity, the internal standard, and the phenol peak.
7. Apparatus
7.1 Gas Chromatograph—Any chromatograph having a flame ionization detector that can be operated at the conditions given in
TABLE 1 Recommended Operating Conditions
Column: To use for identification of all components
Tubing fused silica
Stationary phase polyethylene glycol-acid modified
Solid support crosslinked
Film thickness, μ 0.5
Length, m 50
Inside diameter, m 0.32
Inside diameter, mm 0.32
Carrier Gas Helium. Nitrogen or hydrogen are permitted. Nitrogen
and hydrogen carrier gas require different conditions.
The user must conduct the necessary evaluation to
determine that equivalent results are obtained.
Flow rate mL/min 1.3
Temperature, °C
Injector 180
Detector 230
Oven
Initial, °C 110 for 6 min
Rate, °C 12 per min
Final, °C 210 for 90 min
Internal Standard sec-butyl alcohol
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www.access.gpo.gov.
D6142 − 21
Table 1. The system should have sufficient sensitivity to obtain a minimum peak height response for a 2 mg/kg impurity twice the
height of the signal background noise.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.
7.2 Columns—The choice of column is based on resolution requirements. Any column may be used that is capable of resolving
all significant impurities from the major component. The column and conditions described in Table 1 have been used successfully
and shall be used as referee in cases of dispute.
7.3 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.
8. Reagents
8.1 Purity of Reagent—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.
8.2 High Purity Phenol—Phenol (99.99 % or greater purity).
8.3 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, 1 ppm, less than 0.5 ppm is preferred. Purify carrier, makeup, and detector
gases to remove oxygen, water, and hydrocarbons. Helium was the carrier used for the conditions in Table 1.
8.4 Compressed Air—Purify air to remove water and hydrocarbons. Air for an FID should contain less than 0.1 ppm THC.
8.5 Pure Compounds for Calibration,Equipment Setup Check Sample: shall include mesityl oxide, cumene, hydroxyacetone,
acetone, alpha-methylstyrene, 2-methylbenzofuran, and acetophenone. The purity of all reagents should be 99.9 % or greater. If
the purity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the
standard can be adjusted for the presence of the impurities.
8.5.1 For GC standards, a setup check sample should be included to:
8.5.1.1 Determine retention times for the components measured in GC standards.
8.5.1.2 Verify there is adequate resolution to measure the components of interest in GC standards.
8.5.1.3 Determine that the equipment has the sensitivity specified in the scope of the standard.
8.5.2 For GC standards and standards that determine trace levels, the equipment setup check sample should contain a component
with a concentration that is approximately two times the LOD stated in the scope of the standard. When the equipment setup check
sample is analyzed, an acceptable result for the trace component is 650 % of the expected concentration.
8.5.2.1 For GC standards where the primary material cannot be purified so that no impurities are detected, the following is
suggested:
(1) Add an impurity that is not present in the primary material. Determine that the impurity has the following properties:
(a) The impurity is essentially inert and unreactive in the primary material.
(b) The retention time is sufficiently separated from other impurities so that there will be no mistake in identification.
(c) The impurity is completely vaporized in the injection port.
(d) The impurity is well behaved on the column, that is, no fronting or tailing.
(e) The response factor is known and not significantly different from the components of interest.
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