ASTM D7882-13

Standard Test Method for Determination of 4-Carboxybenzaldehyde and <emph type="bdit" >p</emph>-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Normal 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 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 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 normal voltage mode and UV detection. It is applicable for 4-CBA from 5 to 400 mg/kg and for p-TOL from 10 to 400 mg/kg, respectively.  
1.2 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.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 14-Aug-2013
• ICS: 71.080.40 - Organic acids
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.02 - Oxygenated Aromatics

Standards Content (Sample)

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Designation:D7882 −13
Standard Test Method for
Determination of 4-Carboxybenzaldehyde and p-Toluic Acid
in Purified Terephthalic Acid by Capillary Electrophoresis
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with Normal Voltage Mode
This standard is issued under the fixed designation D7882; 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 ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to
1.1 This test method covers the determination of
Determine the Precision of a Test Method
4-carboxybenzaldehyde (4-CBA) and p-toluic acid (p-TOL) in
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purified terephthalic acid (PTA) by capillary electrophoresis 2.2 ISO Document:
(CE) with normal voltage mode and UV detection. It is EN ISO 8213 Chemical Products for Industrial Use—
applicablefor4-CBAfrom5to400mg/kgandforp-TOLfrom Sampling Techniques—Solid Chemical Products in the
10 to 400 mg/kg, respectively. Form of ParticlesVarying from Powders to Coarse Lumps
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1.2 In determining the conformance of the test results using 2.3 Other Document:
this method to applicable specifications, results shall be OSHA Regulations 29 CFR paragraphs 1910.1000 and
rounded off in accordance with the rounding-off method of 1910.1200
Practice E29.
3. Terminology
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 3.1 Definitions of Terms Specific to Normal Voltage Mode in
standard.
this Standard:
3.1.1 capillary electrophoresis, n—an electrophoretic tech-
1.4 This standard does not purport to address all of the
nique in which a sample is introduced into a 50 to 100 µm i.d.
safety concerns, if any, associated with its use. It is the
fused-silica capillary filled with electrolyte solution and sub-
responsibility of the user of this standard to establish appro-
jected to high voltage for separation.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3.1.1.1 Discussion—Normal voltage, with the anode on the
injection side and the cathode on the detection side, is applied
2. Referenced Documents
across the capillary causing electrolyte and analytes to migrate
2
towards the cathode and through the capillary’s UV detector
2.1 ASTM Standards:
window. Analytes are separated based on the differential rates
D1193 Specification for Reagent Water
of migration in the electric field. Analyte detection and
D4790 Terminology ofAromatic Hydrocarbons and Related
quantitation are based on the principles of UV detection.
Chemicals
D6809 Guide for Quality Control and Quality Assurance
3.1.2 electrolye,n—acombinationofabufferreagentandan
Procedures for Aromatic Hydrocarbons and Related Ma-
ion-pair reagent dissolved in an aqueous solution and placed
terials
inside the capillary, used as a carrier for the analytes.
E29 Practice for Using Significant Digits in Test Data to
3.1.3 electroosmotic flow (EOF), n—the directional velocity
Determine Conformance with Specifications
of electrolyte-solution flow within the capillary under an
E177 Practice for Use of the Terms Precision and Bias in
applied voltage; the velocity and direction of flow are deter-
mined by electrolyte chemistry, capillary-wall chemistry, and
applied voltage (see Fig. 1).
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This test method is under the jurisdiction of ASTM Committee D16 on
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
Subcommittee D16.02 on Oxygenated Aromatics.
Current edition approved Aug. 15, 2013. Published October 2013. DOI:
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10.1520/D7882-13. Available fromAmerican 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.
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contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
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.
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D7882−13
FIG. 1Pictorial Diagram of Charged and Neutral Species Mobilities in CE
3.1.4 electropherogram, n—a graphical presentation of UV method is suitable for setting specifications and for use as an
detector response versus time of analysis; the x-axis is migra- internal quality control where these products are produced or
tion time, which is used to identify the analyte qualitatively, used.
and t
...