EN ISO 25202:2026
(Main)Leather - Chemical analysis - Determination of glutaraldehyde content (ISO 25202:2026)
- Abstract
This document specifies a method for the determination of free and released glutaraldehyde in leathers, using liquid chromatography (LC).
- Status
- Published
- Publication Date
- 13-Oct-2026
- Technical Committee
- CEN/TC 289 - Leather
- Drafting Committee
- CEN/TC 289/WG 1 - Chemical test methods
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 14-Oct-2026
- Due Date
- 11-Nov-2026
- Completion Date
- 14-Oct-2026
EN ISO 25202:2026 is a CEN standard for leather chemical analysis. It specifies a liquid chromatography (LC) method for determining free and released glutaraldehyde in leather, which is useful for laboratories, leather manufacturers, and buyers that need a consistent way to measure this substance.
What does EN ISO 25202:2026 specify?
EN ISO 25202:2026 specifies a test method for leather that measures glutaraldehyde by LC after derivatization. The method is aimed at chemical analysis of leather samples, including material taken from finished products when normal sampling is not possible.
The document is organized into scope, normative references, terms and definitions, principle, reagents, apparatus, specimen preparation, procedure, expression of results, and test report. Annex A gives LC operating conditions, and the bibliography points to a related formaldehyde method in leather.
What are the key requirements of EN ISO 25202:2026?
Clause 4 sets out the measurement principle. EN ISO 25202:2026 separates glutaraldehyde from other aldehydes and ketones, reacts the extract with 2,4-dinitrophenylhydrazine (DNPH), and measures the derivative by reversed-phase LC with UV detection at 355 nm. In practice, the lab is not measuring the raw compound directly but a tagged form that can be separated and quantified.
Sample and extraction requirements
Clause 7 requires sampling in line with ISO 2418 and cutting the leather as described in ISO 4044. If sampling from a finished product is not possible, the test report has to record the sampling details. This matters because the result must be traceable to a defined piece of leather.
Clause 8.1 specifies extraction with a detergent solution at 40 °C for a fixed time, followed by immediate filtration and cooling. The leather-to-solution ratio is not to be changed, and extraction and analysis should be done on the same working day. This keeps the result comparable between laboratories.
Derivatization and LC measurement
Clause 8.1.2 requires mixing the filtered extract with acetonitrile, DNPH solution, and water, then allowing the reaction to stand before membrane filtration and LC analysis. For higher glutaraldehyde levels, a smaller aliquot is used. This step converts the analyte into a form that the LC system can separate and detect reliably.
Clause 8.2 requires calibration with six standard solutions and analysis of samples under the same LC conditions. The calibration range is set so the laboratory can build a graph of concentration against peak area. In practice, the lab needs a valid calibration before reporting any sample result.
Calculation and reporting
Clause 9 requires results to be reported in mg/kg to the nearest 0.1 mg/kg, based on the mass of leather tested. The calculation uses the concentration read from the calibration graph, the dilution factor, the test portion mass, and the detergent-solution volume. Clause 10 then requires the report to identify the standard used, the sample, the date, the result, any unusual observations, and any deviations from the procedure.
Annex A gives the LC settings needed to run the method, including the column type, mobile phase program, temperature, wavelength, flow rate, and injection volume. It also notes how to treat the two peaks that can appear for glutaraldehyde-DNPH on a C18 stationary phase.
What terms does EN ISO 25202:2026 define?
EN ISO 25202:2026 uses these key terms and abbreviations in the method:
- Glutaraldehyde - the analyte measured in leather, reported as free and released glutaraldehyde.
- Free glutaraldehyde - glutaraldehyde present in the extract in measurable form before hydrolysis.
- Released glutaraldehyde - glutaraldehyde that is hydrolysed during extraction and then measured with the free portion.
- LC - liquid chromatography, the separation technique used for quantification.
- DNPH - 2,4-dinitrophenylhydrazine, the reagent used to form detectable hydrazones.
- CAS RN - Chemical Abstracts Service Registry Number, the chemical identifier used for reagents and standards.
- Detergent solution - the extraction solution made with sodium dodecylsulfonate or sodium dodecylsulfate.
Who uses EN ISO 25202:2026?
EN ISO 25202:2026 is used by leather testing laboratories, tanneries, quality control teams, and compliance staff. It is also relevant to buyers and technical managers who need test data for leather raw materials or finished goods such as shoes and garments.
The document supports routine chemical testing, specification checks, product verification, and reporting of glutaraldehyde content in mg/kg. Because it includes sampling, extraction, LC analysis, and reporting rules, it is practical for laboratories that need repeatable results.
Which standards are used with EN ISO 25202:2026?
EN ISO 25202:2026 refers to three normative standards:
- ISO 2418 - gives the position and preparation of specimens for leather testing.
- ISO 3696 - specifies the grade of water used for analytical laboratory work.
- ISO 4044 - covers preparation of chemical test samples from leather.
The bibliography also cites ISO 17226-1, a related leather method for determining formaldehyde by HPLC, which helps place this test within the wider set of leather chemical methods.
What does the EN ISO 25202:2026 document contain?
EN ISO 25202:2026 contains a full step-by-step method for extraction, DNPH reaction, LC analysis, calibration, calculation, and reporting. It gives the apparatus list, reagent specifications, specimen preparation guidance, and a worked calculation approach based on calibration data.
Annex A provides a practical LC set-up, including the mobile phase program, separation column, temperature, detection wavelength, and injection volume. The note under Annex A also explains how to handle the double-peak response of glutaraldehyde-DNPH on the stated column type.
Relations
- Consolidated By
ISO 25202:2026 - Leather — Chemical analysis — Determination of glutaraldehyde content - Effective Date
- 12-Feb-2026
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Frequently Asked Questions
EN ISO 25202:2026 is a draft published by the European Committee for Standardization (CEN). Its full title is "Leather - Chemical analysis - Determination of glutaraldehyde content (ISO 25202:2026)". This standard covers: This document specifies a method for the determination of free and released glutaraldehyde in leathers, using liquid chromatography (LC).
This document specifies a method for the determination of free and released glutaraldehyde in leathers, using liquid chromatography (LC).
EN ISO 25202:2026 is classified under the following ICS (International Classification for Standards) categories: 59.140.30 - Leather and furs. The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 25202:2026 has the following relationships with other standards: It is inter standard links to ISO 25202:2026. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 25202:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 25202:2025
01-februar-2025
Usnje - Kemijska analiza - Določevanje vsebnosti glutaraldehida (ISO/DIS
25202:2024)
Leather - Chemical analysis - Determination of glutaraldehyde content (ISO/DIS
25202:2024)
Leder - Chemische Analyse - Bestimmung des Glutaraldehydgehalts (ISO/DIS
25202:2024)
Cuir - Analyse chimique - Détermination de la teneur en glutaraldéhyde (ISO/DIS
25202:2024)
Ta slovenski standard je istoveten z: prEN ISO 25202
ICS:
59.140.30 Usnje in krzno Leather and furs
71.040.40 Kemijska analiza Chemical analysis
oSIST prEN ISO 25202:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN ISO 25202:2025
oSIST prEN ISO 25202:2025
DRAFT
International
Standard
ISO/DIS 25202
IULTCS
IUC 40
IULTCS
Leather — Chemical analysis —
Secretariat: ISO
Determination of glutaraldehyde
content
Voting begins on:
2024-12-11
ICS: 59.140.30
Voting terminates on:
2025-03-05
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference numbers
ISO/DIS 25202:2024(en)
IULTCS/IUC 40:2024(en)
oSIST prEN ISO 25202:2025
DRAFT
ISO/DIS 25202:2024(en)
International
Standard
ISO/DIS 25202
IULTCS
IUC 40
IULTCS
Leather — Chemical analysis —
Secretariat: ISO
Determination of glutaraldehyde
content
Voting begins on:
ICS: 59.140.30
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2024
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
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RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: copyright@iso.org
Website: www.iso.org
Reference numbers
Published in Switzerland ISO/DIS 25202:2024(en)
IULTCS/IUC 40:2024(en)
ii
oSIST prEN ISO 25202:2025
ISO/DIS 25202:2024(en)
IULTCS/IUC 40:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Preparation of test specimens . 2
8 Procedure . 3
8.1 Sample processing .3
8.1.1 Extraction .3
8.1.2 Reaction with DNPH .3
8.2 Determination by LC .3
9 Expression of results . 4
9.1 General .4
9.2 Calculation of the glutaraldehyde content .4
9.3 Precision of the test method .4
10 Test report . 4
Annex A (informative) LC conditions . 5
Bibliography . 6
iii
oSIST prEN ISO 25202:2025
ISO/DIS 25202:2024(en)
IULTCS/IUC 40:2024(en)
Foreword
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This document was prepared by the European Committee for Standardization (CEN) Technical Committee
CEN/TC 289, Leather, in collaboration with the Chemical Test Commission of the International Union of
Leather Technologists and Chemists Societies (IUC Commission, IULTCS), in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement). This method is technically similar to
the Colorimetric Section of the method IUC 19 which was declared an official method at the IULTCS Delegates
meeting on 31st May 2003 i
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