ASTM D7881-20

Standard Test Method for Determination of 4-Carboxybenzaldehyde and <emph type="bdit" >p</emph>-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode

SIGNIFICANCE AND USE
5.1 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 is also imparting coloration to the polymer due to thermal instability.  
5.2 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 where these products are produced or used.  
5.3 This test method is intended as an alternative to the HPLC method for the determination of 4-CBA and p-TOL in PTA. The major benefits of CE are speed, simplicity, reduced reagent consumption, and operating costs.
SCOPE
1.1 This test method2 covers the determination of 4-carboxybenzaldehyde (4-CBA) and p-toluic acid (p-TOL) in purified terephthalic acid (PTA) by capillary electrophoresis (CE) with reverse voltage mode and UV detection. It is applicable for 4-CBA from 3 to 400 mg/kg and for p-TOL from 8 to 400 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.

General Information

• Status: Historical
• Publication Date: 30-Sep-2020
• ICS: 71.080.40 - Organic acids
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.02 - Oxygenated Aromatics

Standards Content (Sample)

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: D7881 −20
Standard Test Method for
Determination of 4-Carboxybenzaldehyde and p-Toluic Acid
in Purified Terephthalic Acid by Capillary Electrophoresis
1
with Reverse Voltage Mode
This standard is issued under the fixed designation D7881; 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* 2. Referenced Documents
2 3
1.1 This test method covers the determination of 2.1 ASTM Standards:
4-carboxybenzaldehyde (4-CBA) and p-toluic acid (p-TOL) in D1193 Specification for Reagent Water
purified terephthalic acid (PTA) by capillary electrophoresis D6809 Guide for Quality Control and Quality Assurance
(CE) with reverse voltage mode and UV detection. It is Procedures for Aromatic Hydrocarbons and Related Ma-
applicablefor4-CBAfrom3to400mg/kgandforp-TOLfrom terials
8 to 400 mg/kg, respectively. E29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
1.2 In determining the conformance of the test results using
E691 Practice for Conducting an Interlaboratory Study to
thismethodtoapplicablespecification,resultsshallberounded
Determine the Precision of a Test Method
off in accordance with the rounding-off method of Practice
4
2.2 ISO Documents:
E29.
EN ISO 8213 Chemical Products for Industrial Use—
1.3 The values stated in SI units are to be regarded as
Sampling Techniques—Solid Chemical Products in the
standard. No other units of measurement are included in this
Form of ParticlesVarying from Powders to Coarse Lumps
5
standard.
2.3 Other Document:
1.4 This standard does not purport to address all of the OSHA Regulations, 29 CFR paragraphs 1910.1000 and
safety concerns, if any, associated with its use. It is the
1910.1200
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 3.1 DefinitionsofTermsSpecifictoReverseVoltageModein
1.5 This international standard was developed in accor- this Standard:
dance with internationally recognized principles on standard- 3.1.1 capillary electrophoresis, n—an electrophoretic tech-
nique in which a sample is introduced into a 50 µm to 100 µm
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- i. d. fused-silica capillary filled with electrolyte solution and
subjected to high voltage for separation.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 3.1.1.1 Discussion—Reverse voltage, with the cathode on
theinjectionsideandtheanodeonthedetectionside,isapplied
across the capillary causing electrolyte and analytes to migrate
1
This test method is under the jurisdiction of ASTM Committee D16 on
towards the anode and through the capillary’s UV detector
Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-
bility of Subcommittee D16.02 on Oxygenated Aromatics.
3
Current edition approved Oct. 1, 2020. Published December 2020. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 2013. Last previous edition approved in 2019 as D7881 – 19. DOI: contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
10.1520/D7881-20. Standards volume information, refer to the standard’s Document Summary page on
2
This standard is based on SH/T 1687–2000 Purified terephthalic acid for the ASTM website.
4
industrial use—determination of 4-Carboxybenzaldehyde and p-Toluic Acid-High Available from Available from American National Standards Institute (ANSI),
performance capillary electrophoresis (HPCE), copyright SINOPEC, 22 Chaoyang- 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
5
men North Street, Chaoyang District, Beijing, China 100728. A copy of SH/T AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
1687–2000 may be obtained from China Petrochemical Press, www.sinopec- 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
press.com. 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

---------------------- Page: 1 ----------------------
D7881 − 20
window. Analytes are separated based upon the differential 3.1.7.1 Discussion—Nanolitres of sample are introduced
rates of migration in the electrical field.Analyte detection and into the capillary without analyte bias effects.
quantitation are based upon the prin
...

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: D7881 − 19 D7881 − 20
Standard Test Method for
Determination of 4-Carboxybenzaldehyde and p-Toluic Acid
in Purified Terephthalic Acid by Capillary Electrophoresis
1
with Reverse Voltage Mode
This standard is issued under the fixed designation D7881; 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*
2
1.1 This test method covers the determination of 4-carboxybenzaldehyde (4-CBA) and p-toluic acid (p-TOL) in purified
terephthalic acid (PTA) by capillary electrophoresis (CE) with reverse voltage mode and UV detection. It is applicable for 4-CBA
from 3 to 400 mg/kg and for p-TOL from 8 to 400 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
3
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
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
4
2.2 ISO Documents:
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 D7881 – 13.D7881 – 19. DOI: 10.1520/D7881-19.10.1520/D7881-20.
2
This standard is based on SH/T 1687–2000 Purified terephthalic acid for industrial use—determination of 4-Carboxybenzaldehyde and p-Toluic Acid-High performance
capillary electrophoresis (HPCE), copyright SINOPEC, 22 Chaoyangmen North Street, Chaoyang District, Beijing, China 100728. A copy of SH/T 1687–2000 may be
obtained from China Petrochemical Press, www.sinopec-press.com.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
Available from 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
1

---------------------- Page: 1 ----------------------
D7881 − 20
5
2.3 Other Document:
OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200
3. Terminology
3.1 Definitions of Terms Specific to Reverse Voltage Mode in this Standard:
3.1.1 capillary electrophoresis, n—an electrophoretic technique in which a sample is introduced into a 50 μm to 100 μm i. d.
fused-silica capillary filled with electrolyte solution and subjected to high voltage for separation.
3.1.1.1 Discussion—
Reverse voltage, with the cathode on the injection side and the anode on the detection side, is applied across the capillary causing
electrolyte and analytes to migrate towards the anode and through the capillary’s UV detector window. Analytes are separated
based upon the different
...