FprEN ISO 25202
(Main)Leather - Chemical analysis - Determination of glutaraldehyde content (ISO/FDIS 25202:2026)
- Abstract
This document specifies a method for the determination of free and released glutaraldehyde in leathers, using liquid chromatography (LC).
- Status
- Not Published
- Publication Date
- 04-Nov-2026
- Technical Committee
- CEN/TC 289 - Leather
- Drafting Committee
- CEN/TC 289/WG 1 - Chemical test methods
- Current Stage
- 5060 - Closure of Vote - Formal Approval
- Start Date
- 07-Sep-2026
- Completion Date
- 07-Sep-2026
FprEN ISO 25202 is a CEN draft standard for leather chemical analysis. It specifies a liquid chromatography (LC) method for determining free and released glutaraldehyde in leathers, so laboratories can measure this analyte in leather samples.
What does FprEN ISO 25202 specify?
FprEN ISO 25202 specifies a test method for glutaraldehyde in leather using LC. The scope focuses on measuring the free form and the portion released during extraction, which matters in practice because the result reflects what can be extracted from the leather sample under the defined test conditions.
The document is organized into clauses for scope, normative references, terms and definitions, principle, reagents, apparatus, specimen preparation, procedure, expression of results, and test report. Annex A provides LC operating conditions.
| Annex | What it covers |
|---|---|
| Annex A | Informative LC conditions, including an example separation and detection setup |
What are the key requirements of FprEN ISO 25202?
FprEN ISO 25202 works by extracting leather with a detergent solution, converting aldehydes to DNPH derivatives, and separating and measuring them by LC with UV detection. In practice, this means the user prepares the sample, derivatises the extract, and compares it against calibration solutions.
Sample selection and preparation
Clause 7 requires sampling in accordance with ISO 2418 and cutting the leather in accordance with ISO 4044. If ISO 2418 sampling is not possible, for example for finished products such as shoes or garments, the test report must include the sampling details. This matters because the laboratory result is only meaningful if the sample origin and preparation are traceable.
Extraction and derivatisation
Clause 8.1.1 extracts about 2 g of leather pieces with preheated detergent solution at 40 °C for 60 min, then filters and cools the extract. The same leather-to-solution ratio must not be changed, and extraction and analysis should be completed on the same working day. Clause 8.1.2 then mixes a measured aliquot of extract with acetonitrile and DNPH solution, waits at least 60 min, filters, and sends the solution to LC. This sequence matters because the chemical conversion step is part of the measurement, not just sample handling.
Calibration and LC measurement
Clause 8.2 prepares calibration solutions from glutaraldehyde solution or derivatised glutaraldehyde-DNPH solution. The method uses a concentration range that supports leather results from 5 mg/kg to 100 mg/kg under the stated conditions. Clause 8.2.3 then requires the calibration solutions and samples to be analysed on an LC system, with Annex A giving an example setup. For routine work, this tells the laboratory how to build the calibration curve and run the instrument.
Calculation and reporting
Clause 9 requires the result to be expressed to the nearest 0.1 mg/kg. The glutaraldehyde content is calculated from the calibration graph, the dilution factor, the sample mass, and the detergent solution volume. In practice, the analyst must retain the raw calibration data and the sample mass so the reported value can be traced back to the calculation.
Test report content
Clause 10 requires the report to identify the standard used, identify the sample, state the test date and result, and note unusual features or deviations. If the result is based on dry matter, that must also be reported. This supports quality control, audits, and customer-facing documentation.
What terms does FprEN ISO 25202 define?
FprEN ISO 25202 does not list formal terms in Clause 3, but it uses several key technical terms that matter for reading the method:
- Liquid chromatography (LC) - the separation technique used to isolate the glutaraldehyde derivative before UV detection.
- 2,4-dinitrophenylhydrazine (DNPH) - the reagent that reacts with aldehydes and ketones to form hydrazones for measurement.
- Free glutaraldehyde - glutaraldehyde present in the extract without needing hydrolysis.
- Released glutaraldehyde - glutaraldehyde that hydrolyses during extraction and is included in the measured amount.
- Derivative - the chemically modified form measured by the LC system.
- CAS RN - Chemical Abstracts Service Registry Number, the identifier used for listed chemicals in the reagents section.
Who uses FprEN ISO 25202?
FprEN ISO 25202 is used by leather testing laboratories, quality control teams in tanneries and leather product manufacturing, and buyers who specify chemical limits for leather. It is also relevant to technical staff who need a repeatable method for verifying glutaraldehyde content in incoming materials, finished leather, or compliance samples.
Which standards are used with FprEN ISO 25202?
| Standard | What it contributes |
|---|---|
| ISO 2418 | Sampling position and preparation of specimens for testing |
| ISO 3696 | Water quality for analytical laboratory use |
| ISO 4044 | Preparation of chemical test samples for leather |
| ISO 17226-1 | Related leather method for formaldehyde content, cited in the bibliography |
What does the FprEN ISO 25202 document contain?
The document contains the test principle, a reagents list, apparatus requirements, specimen preparation instructions, a step-by-step extraction and DNPH derivatisation procedure, calibration and LC analysis instructions, and the result calculation formula. It also includes reporting requirements for the test report.
Annex A gives example LC measurement conditions, including flow rate, mobile phase composition, column type, temperature, detection wavelength, injection volume, and an example note on peak area handling for glutaraldehyde-DNPH. The document also cites ISO 17226-1 in the bibliography as a related leather chemical test method.
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
FprEN ISO 25202 is a draft published by the European Committee for Standardization (CEN). Its full title is "Leather - Chemical analysis - Determination of glutaraldehyde content (ISO/FDIS 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).
FprEN ISO 25202 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.
FprEN ISO 25202 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.
FprEN ISO 25202 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
Phone: +41 22 749 01 11
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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