ASTM D4794-94(2022)e1

Standard Test Method for Determination of Ethoxyl or Hydroxyethoxyl Substitution in Cellulose Ether Products by Gas Chromatography

ABSTRACT
This test method is applicable to the determination of ethoxyl or hydroxyethoxyl substitution in cellulose ether products by a Zeisel gas chromatographic technique. The equipment and materials to be used shall include reagents, gas chromatograph, electronic integrator, column, syringe, reaction vials, caps, heating block, and a cover. The following reagents are as follows: iodoethane, O-xylene, toluene, hydrochloric acid, and colume packing. When a cellulose ether containing ethyl or hydroxyethyl substitutes is allowed to react with hydriodic acid, one mole of iodoethane is liberated for each mole of ethoxyl or hydroxyethoxyl ether substituted on the cellulose chain. The iodoethane is extracted in-situ with o-xylene and quantitated by gas chromatography using an internal standard technique. It is recommended to run duplicate samples.
SCOPE
1.1 This test method is applicable to the determination of ethoxyl or hydroxyethoxyl substitution in cellulose ether products by a Zeisel gas chromatographic technique.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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 5 and 9.1.8.1.  
1.4 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: Published
• Publication Date: 31-May-2022
• ICS: 71.080.60 - Alcohols. Ethers
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.36 - Cellulose and Cellulose Derivatives

Overview

ASTM D4794-94(2022)e1 is a standard test method developed by ASTM International for the precise determination of ethoxyl or hydroxyethoxyl substitution in cellulose ether products using gas chromatography. This method employs a Zeisel gas chromatographic technique to quantify the variation in substituent levels of cellulose ethers, offering important analytical data for product quality control, research, and regulatory compliance across multiple industries.

Key Topics

• Zeisel Gas Chromatographic Technique: Utilizes chemical reactions and gas chromatography to measure ethoxyl and hydroxyethoxyl groups in cellulose ethers.
• Reagents and Apparatus:
  • Key chemicals: iodoethane, o-xylene, toluene, and hydriodic acid.
  • Essential equipment: gas chromatograph with thermal conductivity detector, reaction vials, heating blocks, electronic integrators, and stainless steel columns.
• Analytical Process:
  • Cellulose ethers react with hydriodic acid, releasing iodoethane in proportion to the level of ethoxyl or hydroxyethoxyl substitution.
  • The liberated iodoethane is extracted and quantified by gas chromatography using an internal standard (toluene).
• Precision and Units: Results are reported in SI units. Duplicate testing is recommended to ensure accuracy and reliability.
• Safety and Compliance: Users must observe all safety, health, and environmental protocols due to the use of aggressive reagents and potential pressurization during reactions.

Applications

ASTM D4794-94(2022)e1 is highly valuable for organizations involved in the production and quality assurance of cellulose ether products. Typical application areas include:

• Quality Control in Manufacturing: Ensuring product specifications for ethoxyl or hydroxyethoxyl substitution are met in cellulose-based additives used in paints, coatings, food products, construction materials, and pharmaceuticals.
• Product Development and Research: Facilitating formulation adjustments and validation by precisely measuring chemical modification levels.
• Regulatory Compliance and Documentation: Generating standardized data needed in product certifications and regulatory submissions.
• Comparative Assessment: Evaluating different batches or supplier lots for consistency in cellulose ether substitution profiles.

Organizations that benefit from this method include manufacturers, analytical laboratories, and industries where cellulose ethers serve as thickeners, stabilizers, or binding agents.

Related Standards

These ASTM standards and related international documents may be relevant when working with cellulose ethers and chromatographic testing:

• ASTM D1439 - Test Method for Sodium Carboxymethylcellulose
• ASTM E260 - Practice for Packed Column Gas Chromatography
• ISO 17025 - General requirements for the competence of testing and calibration laboratories
• ASTM D1795 - Test Method for Intrinsic Viscosity of Cellulose
• ISO 9001 - Quality management systems (for quality assurance processes)

For comprehensive quality and regulatory strategies concerning cellulose ethers and analytical lab methods, aligning ASTM D4794-94(2022)e1 with the above standards is highly recommended.

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Keywords: cellulose ether, ethoxyl substitution, hydroxyethoxyl substitution, gas chromatography, ASTM D4794, Zeisel method, quality control, analytical chemistry, internal standard, laboratory testing

Standards Content (Sample)

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.
´1
Designation: D4794 − 94 (Reapproved 2022)
Standard Test Method for
Determination of Ethoxyl or Hydroxyethoxyl Substitution in
Cellulose Ether Products by Gas Chromatography
This standard is issued under the fixed designation D4794; 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.
ε NOTE—Editorial update made to 1.3 and 9.1.8 in June 2022.
1. Scope 3.3 Column—stainless steel, 1829 mm in length, 3.2 mm in
outside diameter, packed with the reagent in 4.6, coiled to fit
1.1 This test method is applicable to the determination of
the chromatograph used; or equivalent column and packing as
ethoxyl or hydroxyethoxyl substitution in cellulose ether prod-
appropriate.
ucts by a Zeisel gas chromatographic technique.
3.4 Syringe, 10 µL.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 3.5 Reaction Vials, Caps, and Heating Block.
standard.
3.6 Syringe,100µL.
1.3 This standard does not purport to address all of the
3.7 Cover, stainless steel, fabricated to cover the heating
safety concerns, if any, associated with its use. It is the
block.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Reagents and Materials
mine the applicability of regulatory limitations prior to use.
4.1 Purity of Reagents—Reagent grade chemicals shall be
For specific hazard statements, see Section 5 and 9.1.8.1.
used in all tests. Unless otherwise indicated, it is intended that
1.4 This international standard was developed in accor-
all reagents shall conform to the specifications of the Commit-
dance with internationally recognized principles on standard-
tee onAnalytical Reagents of theAmerican Chemical Society,
ization established in the Decision on Principles for the
where such specifications are available. Other grades may be
Development of International Standards, Guides and Recom-
used, provided it is first ascertained that the reagent is of
mendations issued by the World Trade Organization Technical
sufficiently high purity to permit its use without lessening the
Barriers to Trade (TBT) Committee.
accuracy of the determination.
2. Summary of Test Method
4.2 Iodoethane, 99 % minimum.
2.1 When a cellulose ether containing ethyl or hydroxyethyl
4.3 O-xylene.
substitutes is allowed to react with hydriodic acid, one mole of
4.4 Toluene.
iodoethane is liberated for each mole of ethoxyl or hydroxy-
ethoxyl ether substituted on the cellulose chain. The iodoeth- 4.5 Hydriodic Acid, 57 % (sp gr 1.69 to 1.70).
ane is extracted in situ with o-xylene and quantitated by gas
4.6 Column Packing, 10 % methyl silicone stationary phase
chromatography using an internal standard technique. It is
USP code [G1] coated on inert diatomite solid support USP
recommended to run duplicate samples.
code [S1A], 100/120 mesh.
3. Apparatus
3.1 Gas Chromatograph with thermal conductivity detector
The sole source of supply of a heating block, Silli-Therm Heating Module,
and heated injection port.
Reacti-Block 21, Reacti-Vials, and Minnert valve tops, known to the committee at
this time is the Pierce Chemical Company P.O. Box 117, Rockford, IL61105–9976.
3.2 Electronic Integrator.
If you are aware of alternative suppliers, please provide this information to ASTM
International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
1 3
This test method is under the jurisdiction of ASTM Committee D01 on Paint ACS Reagent Chemicals, Specifications and Procedures for Reagents and
and Related Coatings, Materials, andApplications and is the direct responsibility of Standard-Grade Reference Materials, American Chemical Society, Washington,
Subcommittee D01.36 on Cellulose and Cellulose Derivatives. DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
CurrenteditionapprovedJune1,2022.PublishedJuly2022.Originallyapproved Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
in 1988. Last previous edition approved in 2017 as D4794 – 94 (2017). DOI: U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
10.1520/D4794-94R22E01. copeial Convention, Inc. (USPC), Rockville, MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D4794 − 94 (2022)
5. Hazards 8.1.1 Calibrate the integrator according to the manufactur-
er’s instructions.
5.1 Safety precautions must be taken for handling of hydri-
odic acid. 8.2 If an integrator is not available peak areas and response
factors can be determined manually as follows:
5.2 During the reaction, the glass vials are under pressure.
Exercise precaution in handling the hot vials. A 3 w 3 P 3 F
RF 5 (1)
0.05 3 B 3 P
6. Apparatus Preparation and Conditioning
where:
6.1 Column (Note 1)—Columns are packed with reagent
RF = response factor,
under vacuum and mechanical vibration using silanized glass
A = peak height of internal standard (toluene),
wool to contain the packing. Install each in the gas chromato
...