ISO 25122

• Abstract:

  This document specifies a gas chromatographic (GC) method for the determination of traces of carbon monoxide and carbon dioxide in ethylene and propylene for industrial use. This document is applicable to ethylene and propylene having carbon monoxide and carbon dioxide concentrations greater than 0,5 mL/m3.

• Status: Not Published
• ICS: 71.040.40 - Chemical analysis
• ICS: 71.080.10 - Aliphatic hydrocarbons
• Technical Committee: ISO/TC 47 - Chemistry
• Drafting Committee: ISO/TC 47/WG 2 - Light Olefins
• Current Stage: 6000 - International Standard under publication
• Start Date: 09-Sep-2026
• Completion Date: 12-Sep-2026

Overview

ISO 25122:2026 defines the standardized gas chromatographic (GC) method for determining traces of carbon monoxide (CO) and carbon dioxide (CO₂) in ethylene and propylene intended for industrial use. Developed by ISO/TC 47 (Chemistry), this standard ensures accurate, repeatable, and reliable quantification of trace contaminants in these key feedstock gases, supporting quality control and compliance in the chemical and petrochemical industries. The test method is applicable to ethylene and propylene samples with CO and CO₂ concentrations above 0.5 mL/m³.

Key Topics

• Gas Chromatography (GC) Techniques:
  The standard focuses on GC analysis equipped with a flame ionization detector (FID) for quantifying small amounts of carbon monoxide and carbon dioxide.

• Methanization Process:
  A methanizer is used to convert CO and CO₂ into methane for effective FID detection, utilizing catalytic hydrogenation at 350–400 °C.

• Sampling Procedures:
  The approach references ISO 7382 for ethylene and ISO 8563 for propylene to ensure representative sampling, whether samples are in the gaseous or liquid phase.

• Calibration and Quality Assurance:
  Detailed procedural steps for calibration, sample injection, and ongoing quality control using certified reference gases or internally prepared standards.

• Equipment Requirements:

  • Gas chromatographs with designated columns and detectors
  • Gas standards and high-purity reagent gases
  • Data processing software for accurate measurement and reporting

• Precision and Reporting:
  The standard stipulates repeatability and reproducibility conditions and provides clear guidelines for test reporting, essential for laboratory quality protocols.

Applications

The ISO 25122 method is essential for:

• Industrial Gas Production and Supply:
  Ensuring bulk ethylene and propylene meet purity specifications by quantifying trace CO and CO₂ levels.

• Petrochemical Process Control:
  Maintaining high-quality raw material for downstream processes such as polymerization, where the presence of contaminants can affect catalytic reactions and final product quality.

• Regulatory Compliance:
  Meeting contractual and statutory requirements on trace contaminant levels in feed gases as specified by international and national authorities.

• Quality Assurance in Chemical Manufacturing:
  Supporting internal and third-party laboratory verification of gas quality, reducing risk of process upsets and equipment fouling due to impurities.

Related Standards

• ISO 7382:
  Ethylene for industrial use - Sampling in the liquid and the gaseous phase
  Describes sampling methods for ethylene which are referenced in ISO 25122.

• ISO 8563:
  Propylene and butadiene for industrial use - Sampling in the liquid phase
  Provides essential procedures for proper sampling of propylene.

• Other Relevant Standards:
  Laboratories may refer to related ISO and IEC documents for broader guidance on analytical methods and laboratory competence.

By following ISO 25122, organizations benefit from a globally recognized method for monitoring trace levels of carbon monoxide and carbon dioxide in critical raw materials, enabling consistent product quality in industrial operations and compliance with industry regulations. For up-to-date information or implementation guidance, contact your local ISO member body or visit the ISO website.

International
Standard
First edition
Ethylene and propylene for
industrial use — Determination
of traces of carbon monoxide
and carbon dioxide — Gas
chromatographic method
PROOF/ÉPREUVE
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
5.1 Nitrogen .2
5.2 Hydrogen .2
5.3 Air .2
5.4 Gas standard .2
6 Apparatus . 2
6.1 Gas Chromatography .2
6.2 Column .4
6.3 Methanizer .6
6.4 Data processing equipment .6
7 Sampling . 6
8 Procedure . 6
8.1 Preparation of Apparatus .6
8.2 Calibration .6
8.3 Sample measurement .7
9 Calculation . 7
10 Reporting . 7
11 Precision . 7
11.1 Repeatability (r) .7
11.2 Reproducibility (R) .7
12 Quality Assurance . 8
13 Test report . 8
PROOF/ÉPREUVE
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 47, Chemistry.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
PROOF/ÉPREUVE
iv
International Standard ISO 25122:2026(en)
Ethylene and propylene for industrial use — Determination
of traces of carbon monoxide and carbon dioxide — Gas
chromatographic method
1 Scope
This document specifies a gas chromatographic (GC) method for the determination of traces of carbon
monoxide and carbon dioxide in ethylene and propylene for industrial use.
This document is applicable to ethylene and propylene having carbon monoxide and carbon dioxide
concentrations greater than 0,5 mL/m .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 7382, Ethylene for industrial use — Sampling in the liquid and the gaseous phase
ISO 8563, Propylene and butadiene for industrial use — Sampling in the liquid phase
3 Terms and definitions
No terms and definitions need to be defined in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso
...

ISO/DISPRF 25122:2026(en)
ISO/TC 47
Secretariat: JISC
Date: 2026-06-1608-11
Ethylene and propylene for industrial use — Determination of traces
of carbon monoxide and carbon dioxide — — Gas chromatographic
method
PROOF
ISO/PRF 25122:2026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO/DIS 25122 2026 – All rights reserved
ii
ISO/DISPRF 25122:2026(en)
Contents
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
5.1 Nitrogen . 2
5.2 Hydrogen . 2
5.3 Air . 2
5.4 Gas standard . 2
6 Apparatus . 2
6.1 Gas Chromatography . 2
6.2 Column . 4
6.3 Methanizer . 7
6.4 Data processing equipment . 7
7 Sampling . 8
8 Procedure . 8
8.1 Preparation of Apparatus . 8
8.2 Calibration . 8
8.3 Sample measurement . 8
9 Calculation . 8
10 Reporting . 8
11 Precision . 9
11.1 Repeatability (r) . 9
11.2 Reproducibility (R) . 9
12 Quality Assurance . 9
13 Test report . 9

Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 1
6 Apparatus . 2
7 Sampling . 6
8 Procedure . 7
9 Calculation . 7
10 Reporting . 7
11 Precision . 7
iii
ISO/PRF 25122:2026(en)
12 Quality Assurance . 8
13 Test report . 8
iv © ISO/DIS 25122 2026 – All rights reserved
iv
ISO/DISPRF 25122:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 47, Chemistry.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.htmlwww.iso.org/members.html.

v
DRAFT International Standard ISO/DIS 25122:2026(en)

Ethylene and Propylenepropylene for Industrial Use industrial use —
Determination of Tracestraces of Carbon Monoxidecarbon monoxide
and Carbon Dioxidecarbon dioxide — Gas Chromatographic
Methodchromatographic method
1 Scope
This document specifies a gas chromatographic (GC) method for the determination of traces of carbon
monoxide and carbon dioxide in ethylene and propylene for industrial use.
This document is applicable to ethylene and propylene having carbon monoxide and carbon dioxide
concentrations greater than 0,5 mL/m .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 7382, Ethylene for indus
...