ASTM D7884-20

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: D7884 − 19 D7884 − 20
Standard Test Method for
Determination of 4-Carboxybenzaldehyde and p-Toluic Acid
in Purified Terephthalic Acid by Reverse Phase High
1
Performance Liquid Chromatography
This standard is issued under the fixed designation D7884; 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 4-Carboxybenzaldehyde (4-CBA) and p-Toluic acid (p-TOL) in purified
terephthalic acid (PTA) by reverse phase high performance liquid chromatography (HPLC). This method is applicable for 4-CBA
from 2 to 500 mg/kg and for p-TOL from 10 to 500 mg/kg, respectively.
1.2 In determining the conformance of the test results using this method to applicable specification, results shall be rounded off
in accordance with the rounding-off method of Practice E29.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
1.5 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
2.1 ASTM Standards:
D1193 Specification for Reagent Water
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
E682 Practice for Liquid Chromatography Terms and Relationships
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 ISO Document:
EN ISO 8213 Chemical products for industrial use—Sampling techniques—Solid chemical products in the form of particles
varying from powders to coarse lumps
1
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 D16.02 on Oxygenated Aromatics.
Current edition approved Nov. 1, 2019Oct. 1, 2020. Published December 2019December 2020. Originally approved in 2013. Last previous edition approved in 20132019
as D7884 – 13.D7884 – 19. DOI: 10.1520/D7884-19.10.1520/D7884-20.
2
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.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
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D7884 − 20
4
2.3 Other Document:
OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200
3. Summary of Test Method
3.1 Reverse Phase HPLC Method—PTA sample is dissolved in ammonium hydroxide solution, and a fixed volume of this solution
is injected into a high performance liquid chromatograph equipped with a UV detector. A C18 chemically bonded column is used
to separate the impurities 4-CBA and p-TOL from PTA. The external standard calibration is used for quantification.
4. Significance and Use
4.1 The presence of 4-CBA and p-TOL in PTA used for the production of polyester is undesirable because they can slow down
the polymerization process and 4-CBA imparts coloration to the polymer due to thermal instability.
4.2 Determining the amount of 4-CBA and p-TOL remaining from the manufacture of PTA is often required. This test method is
suitable for setting specifications and for use as an internal quality control tool where these products are produced or are used.
5. Apparatus
5.1 High Performance Liquid Chromatograph (HPLC)—Any HPL
...

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7884 − 20
Standard Test Method for
Determination of 4-Carboxybenzaldehyde and p-Toluic Acid
in Purified Terephthalic Acid by Reverse Phase High
1
Performance Liquid Chromatography
This standard is issued under the fixed designation D7884; 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* Procedures for Aromatic Hydrocarbons and Related Ma-
terials
1.1 This test method covers the determination of the
E29 Practice for Using Significant Digits in Test Data to
4-Carboxybenzaldehyde (4-CBA) and p-Toluic acid (p-TOL)
Determine Conformance with Specifications
in purified terephthalic acid (PTA) by reverse phase high
E682 Practice for Liquid Chromatography Terms and Rela-
performance liquid chromatography (HPLC). This method is
tionships
applicable for 4-CBA from 2 to 500 mg/kg and for p-TOL from
E691 Practice for Conducting an Interlaboratory Study to
10 to 500 mg/kg, respectively.
Determine the Precision of a Test Method
1.2 In determining the conformance of the test results using 3
2.2 ISO Document:
this method to applicable specification, results shall be rounded
EN ISO 8213 Chemical products for industrial use—
off in accordance with the rounding-off method of Practice
Sampling techniques—Solid chemical products in the
E29.
form of particles varying from powders to coarse lumps
4
1.3 The values stated in SI units are to be regarded as
2.3 Other Document:
standard. No other units of measurement are included in this
OSHA Regulations, 29 CFR paragraphs 1910.1000 and
standard.
1910.1200
1.4 This standard does not purport to address all of the
3. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1 Reverse Phase HPLC Method—PTA sample is dissolved
in ammonium hydroxide solution, and a fixed volume of this
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. solution is injected into a high performance liquid chromato-
1.5 This international standard was developed in accor- graph equipped with a UV detector. A C18 chemically bonded
dance with internationally recognized principles on standard- column is used to separate the impurities 4-CBA and p-TOL
ization established in the Decision on Principles for the from PTA. The external standard calibration is used for
Development of International Standards, Guides and Recom- quantification.
mendations issued by the World Trade Organization Technical
4. Significance and Use
Barriers to Trade (TBT) Committee.
4.1 The presence of 4-CBA and p-TOL in PTA used for the
2. Referenced Documents
production of polyester is undesirable because they can slow
2
down the polymerization process and 4-CBA imparts color-
2.1 ASTM Standards:
ation to the polymer due to thermal instability.
D1193 Specification for Reagent Water
D6809 Guide for Quality Control and Quality Assurance
4.2 Determining the amount of 4-CBA and p-TOL remain-
ing from the manufacture of PTA is often required. This test
method is suitable for setting specifications and for use as an
1
This test method is under the jurisdiction of ASTM Committee D16 on
internal quality control tool where these products are produced
Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-
or are used.
bility of Subcommittee D16.02 on Oxygenated Aromatics.
Current edition approved Oct. 1, 2020. Published December 2020. Originally
approved in 2013. Last previous edition approved in 2019 as D7884 – 19. DOI:
3
10.1520/D7884-20. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 4th Floor, New York, NY 10036, http://www.ansi.org.
4
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from U.S. Government Printing Office Superintendent of Documents,
Standards volume information, refer to the standard’s Document Summary page on 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
the ASTM website. www.access.gpo.gov.
*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

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D7884 − 20
5
5. Apparatus Society, where such specifications are available. Other grades
may be used, provided it is first ascertained that the reagent is
5.1 High Performance Liquid Chromatograph (HPLC)—
of sufficiently high
...