SIST EN ISO 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
• Public Enquiry End Date: 27-Feb-2025
• ICS: 59.140.30 - Leather and furs
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: IUSN - Leather
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 26-Oct-2026
• Due Date: 31-Dec-2026
• Ref Project: EN ISO 25202:2026 - Leather - Chemical analysis - Determination of glutaraldehyde content (ISO 25202:2026)

SIST EN ISO 25202:2026 is a standard for leather chemical analysis. It specifies an LC method for determining free and released glutaraldehyde in leather, for use in laboratory testing.

What does SIST EN ISO 25202:2026 specify?

SIST EN ISO 25202:2026 specifies a method for measuring glutaraldehyde content in leather by liquid chromatography (LC). The scope covers free glutaraldehyde and glutaraldehyde released during extraction.

The document is organized into clauses on scope, normative references, terms and definitions, principle, reagents, apparatus, specimen preparation, procedure, expression of results, and test report, followed by one informative annex.

Annex	What it covers
Annex A	LC conditions, including example measurement conditions and a note on peak handling

What are the key requirements of SIST EN ISO 25202:2026?

SIST EN ISO 25202:2026 is built around extraction, derivatization, LC separation, and calculation from a calibration graph. In practice, it gives a laboratory a full workflow from leather sampling to the reported result.

• Sampling and specimen preparation - Clause 7 requires sampling in accordance with ISO 2418 and cutting leather in accordance with ISO 4044. If sampling from finished products is not possible, the sampling details must be included in the test report. This matters because the result is only as representative as the specimen taken.

• Extraction of the leather sample - Clause 8.1.1 calls for about 2 g of leather pieces, extracted with 50 ml of detergent solution at 40 °C for 60 minutes in a shaken water bath. The leather/solution ratio must not be changed, and extraction and analysis should be carried out on the same working day. This keeps the test conditions comparable from sample to sample.

• Reaction with DNPH - Clause 8.1.2 mixes the filtered extract with acetonitrile and 2,4-dinitrophenylhydrazine (DNPH), then allows at least 60 minutes for reaction before LC analysis. For samples with higher glutaraldehyde content, smaller aliquots are used. This step converts aldehydes into measurable derivatives.

• Calibration approach - Clause 8.2.1 and 8.2.2 describe calibration solutions prepared from either glutaraldehyde solution or derivatized glutaraldehyde-DNPH solution. The example calibration range is 0.1 µg/ml to 2.0 µg/ml, corresponding under the stated conditions to 5 mg/kg to 100 mg/kg in leather. This gives the laboratory the range over which to build the calibration graph.

• LC measurement - Clause 8.2.3 requires analysis by LC with UV detection, and Annex A gives example conditions for the LC system. The annex includes a reversed-phase C18 column, a 30 °C column temperature, 10 µl injection volume, and detection at (355 ± 5) nm. This is the practical set-up used to separate and measure the derivative.

• Evaluation of the chromatogram - Clause 4 states that glutaraldehyde is separated and quantified as a derivative from other aldehydes and ketones. The note in Annex A says that, with a C18 reversed-phase column, glutaraldehyde-DNPH gives two peaks and the calibration area is the sum of both peaks. This matters when integrating chromatograms so the reported value reflects the whole derivative signal.

• Reporting the result - Clause 9 requires the glutaraldehyde content to be expressed to the nearest 0.1 mg/kg. The result is calculated from the calibration graph and the sample mass, using the formula given in Clause 9.2. This gives a single result that can be compared with internal specifications or customer requirements.

Who uses SIST EN ISO 25202:2026?

SIST EN ISO 25202:2026 is used by leather testing laboratories, quality control teams, manufacturers, and buyers who need to measure glutaraldehyde in leather. It is relevant for routine chemical analysis of leather materials and for checking samples from finished products such as shoes or garments.

Which standards are used with SIST EN ISO 25202:2026?

SIST EN ISO 25202:2026 cites three normative references that support the method:

• ISO 2418 - gives the position and preparation of leather specimens for testing.
• ISO 3696 - specifies the water quality required for analytical laboratory use.
• ISO 4044 - covers preparation of chemical test samples from leather.

These referenced standards help ensure that sampling, water quality, and sample preparation are handled consistently before the LC measurement begins.

What does the SIST EN ISO 25202:2026 document contain?

The document contains the method principle, reagent list, apparatus list, specimen preparation instructions, step-by-step extraction and derivatization procedures, calibration instructions, and the calculation and reporting approach. It also includes an informative annex with example LC conditions and a bibliographic reference to ISO 17226-1.

Clause 8 gives the detailed laboratory procedure, including extraction, DNPH reaction, filtration, and LC analysis. Clause 9 gives the calculation path from calibration graph to mg/kg result, and Clause 10 lists the items that must appear in the test report.

Annex A provides the measurement conditions used as an example for the LC system. It is the part to consult when setting up the chromatographic method in the laboratory.

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
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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
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NATIONAL REGULATIONS.
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RECIPIENTS OF THIS DRAFT ARE INVITED
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NOTIFICATION OF ANY RELEVANT PATENT
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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
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
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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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/had not] received notice of
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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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