ISO 23822:2026

• Abstract:

  This document specifies a liquid chromatography tandem mass spectrometry method (LC-MS/MS) for the determination of nitroimidazole residues in eggs and egg products. This document is applicable to eggs and egg products, including whole eggs (fresh, frozen or pasteurized), egg yolk (liquid, frozen, dried or pasteurized), egg white (liquid, frozen, dried or pasteurized), whole egg powder, egg white powder, egg yolk powder, and liquid or dried albumin preparations.

• Status: Published
• Publication Date: 29-Jun-2026
• ICS: 67.120.20 - Poultry and eggs
• Technical Committee: ISO/TC 34/SC 6 - Meat, poultry, fish, eggs and their products
• Drafting Committee: ISO/TC 34/SC 6 - Meat, poultry, fish, eggs and their products
• Current Stage: 6060 - International Standard published
• Start Date: 30-Jun-2026
• Due Date: 28-Nov-2026
• Completion Date: 30-Jun-2026

Overview

ISO 23822:2026 – Eggs and egg products – Determination of nitroimidazole residues - Liquid chromatography-tandem mass spectrometry method sets out an internationally harmonized procedure for quantifying nitroimidazole residues in eggs and egg-derived products using LC-MS/MS (liquid chromatography-tandem mass spectrometry). Developed under ISO/TC 34/SC 6, this standard ensures food safety compliance and supports quality assurance for eggs and egg products (including fresh, frozen, pasteurized, and powdered formats). Implementing ISO 23822:2026 enables laboratories and regulatory authorities to reliably detect and confirm the presence of nitroimidazole residues, ensuring that products meet legal and safety requirements.

Key Topics

• Nitroimidazole Residues: This standard covers the determination of several nitroimidazole compounds, including metronidazole, dimetridazole, ronidazole, ipronidazole, and their hydroxy derivatives-substances of concern due to their banned or limited use in food-producing animals.
• Applicability: Applicable to a wide range of egg and egg product matrices:
  • Whole eggs (fresh, frozen, pasteurized)
  • Egg yolk and white (liquid, frozen, dried, pasteurized)
  • Egg powders (whole, yolk, white)
  • Albumin preparations
• Sample Preparation: Detailed protocols for homogenizing, reconstituting, and storing test samples to minimize alterations and maintain integrity.
• Analytical Method: Outlines the full LC-MS/MS workflow, including:
  • Extraction using acetonitrile
  • Purification with solid-phase extraction cartridges
  • Analytical separation via HPLC and detection by mass spectrometry
  • Use of isotope-labelled internal standards for quantification
• Validation and Performance: Specifies method sensitivity with defined limits of detection (0.4 µg/kg) and quantification (1.0 µg/kg), and includes collaborative data on precision (coefficient of variation < 20%).
• Reporting Requirements: Ensures clear documentation of results, sampling, and any deviations from the procedure.

Applications

The ISO 23822:2026 standard is directly applicable to:

• Food Safety Laboratories: Assists in routine monitoring and regulatory surveillance of eggs and egg-based ingredients for unauthorized nitroimidazole residues.
• Food Industry Quality Control: Supports internal quality checks for producers, processors, and exporters, ensuring that egg products comply with international residue limits and trade requirements.
• Regulatory Authorities: Enables enforcement of residue legislation and facilitates international trade by harmonizing residue detection protocols.
• Research and Development: Provides a validated method for studying residue depletion, validating new egg-based matrices, and supporting development of alternative analytical techniques.

By establishing a standardized approach to nitroimidazole residue determination in eggs, ISO 23822:2026 promotes consumer confidence, helps prevent food fraud, and supports public health initiatives against the misuse of veterinary drugs.

Related Standards

• ISO 3696: Water for analytical laboratory use - Specification and test methods (referenced for reagent preparation).
• CAC/GL 50-2004: General Guidelines on Sampling (recommended for collecting representative egg samples).
• ISO 5725-2: Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method.

These related standards ensure compatibility with recognized laboratory practices and global food safety frameworks. For further guidance on veterinary drug residue testing in food, consult sector-specific ISO and Codex standards.

Keywords: ISO 23822, nitroimidazole residues, eggs, egg products, LC-MS/MS, food safety, residue analysis, metronidazole, regulatory compliance, standard method, food testing, laboratory methods, international food standards, analytical chemistry.

International
Standard
ISO 23822
First edition
Eggs and egg products —
2026-06
Determination of nitroimidazole
residues — Liquid chromatography-
tandem mass spectrometry method
Œufs et ovoproduits — Dosage des résidus de nitroimidazole
— Méthode de chromatographie en phase liquide couplée à la
spectrométrie de masse en tandem
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Sampling . 1
6 Preparation of test sample . 2
6.1 Preparation of sample .2
6.1.1 Fresh eggs and egg products with shell.2
6.1.2 Other egg products .2
6.2 Storage .2
7 Reagents and materials . 2
7.1 Reagents .2
7.2 Preparation of solution .2
7.3 Standards .3
7.4 Preparation of standard solution . .3
7.5 Materials .4
8 Apparatus . 4
9 Procedure . 4
9.1 General .4
9.2 Extraction .4
9.3 Purification .4
9.4 LC-MS/MS analysis .4
9.4.1 HPLC conditions .4
9.4.2 MS parameters .5
9.5 Confirmation .6
9.5.1 Retention time .6
9.5.2 Ion abundance ratios .6
9.6 Quantification . . .6
9.7 Blank test .6
9.8 Calculation .7
9.9 Limits of detection .7
9.10 Limits of quantification .7
9.11 Precision . . .7
10 Test report . 7 ®
Annex A (informative) Compound name, CAS Registry Number , molecular formula, relative
molecular mass and structural formula . 8
Annex B (informative) LC-MS/MS chromatograms of the quantification ion pairs for
nitroimidazoles from the mixed standard solution . 9
Annex C (informative) Collaborative interlaboratory test result .16
Bibliography . 17

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 6, Meat,
poultry, fish, eggs and their products.
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.

iv
International Standard ISO 23822:2026(en)
Eggs and egg products — Determination of nitroimidazole
residues — Liquid chromatography-tandem mass
spectrometry method
1 Scope
This document specifies a liquid chromatography tandem mass spectrometry method (LC-MS/MS) for the
determination of nitroimidazole residues in eggs and egg products.
This document is applicable to eggs and egg products, including whole eggs (fresh, frozen or pasteurized),
egg yolk (liquid, frozen, dried or pasteurized), egg white (liquid, frozen, dried or pasteurized), whole egg
powder, egg white powder, egg yolk powder, and liquid or dried albumin preparations.
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 3696, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
nitroimidazole residues
compounds including metronidazole, dimetridazole, ronidazole, ipronidazole, hydroxymetronidazole,
hydroxydimetridazole and hydroxyipronidazole
4 Principle
The test sample is extracted using acetonitrile. The extracted solution is purified through solid-phase
extraction. The nitroimidazole residues are determined and confirmed by LC-MS/MS, and quantified with
an internal standard method.
5 Sampling
Sampling is not part of the method specified in this document. A recommended sampling method is given in
CAC/GL 50-2004.
It is essential that the laboratory receives a sample which is truly representative and remains unaffected by
damage or change during transport or storage.
Start from a representative sample of at least 1 kg.

Store the sample in such a way that deterioration and change in composition are prevented.
6 Preparation of test sample
6.1 Preparation of sample
6.1.1 Fresh eggs and egg products with shell
Take 16 (about 1 kg) fresh eggs or egg products and remove the shells. Homogenize the egg contents sample
with the appropriate equipment. Transfer the homogenized sample into a polyethylene bottle.
6.1.2 Other egg products
Homogenize the egg products samples thoroughly. Transfer the homogenized sample into a polyethylene
bottle.
For concentrated or dried egg products, weigh 5 g (to the nearest 0,01 g) of the homogenized sample into a
50 ml centrifuge tube, add 20 ml of water for reconstitution, vortex for 10 min, and then sonicate for 10 min.
Ensure that the sample is evenly dispersed to obtain the reconstituted egg solutions.
NOTE This step is necessary to reconstitute dried (e.g. egg powder) or concentrated egg products to their ready-
to-use form by diluting them to the required concentration. Liquid and frozen products are already in a suitable state
for analysis and can bypass this procedure.
6.2 Storage
Store the test sample and standby sample at a temperature between −20 °C and −16 °C.
7 Reagents and materials
Reagents shall be of recognized analytical grade, unless otherwise specified.
7.1 Reagents
7.1.1 Water, grade 1 in accordance with ISO 3696.
7.1.2 Acetonitrile (CH CN), HPLC grade.
7.1.3 Methanol (CH OH), HPLC grade.
7.1.4 Formic acid (HCOOH), HPLC grade.
7.1.5 Sodium chloride (NaCl).
7.1.6 Dimethyl sulfoxide (DMSO).
7.1.7 n-Hexane (C H ).
6 14
7.2 Preparation of solution
7.2.1 10 % Methanol aqueous solution (containing 0,1 % formic acid).
Pipette 10 ml of methanol and 0,1 ml of formic acid into a 100 ml one-mark volumetric flask. Dilute to the
mark with water and mix.
...