veterinary drug residues

working group on veterinary drug residues

The working group was founded in 1985 and consists of active and corresponding members who come from authorities and institutions of official food monitoring, from independent private laboratories, from the food industry and universities. The active members meet twice a year in Frankfurt (Main) for working group meetings. Active and corresponding members have the opportunity to view and download the minutes of the working group meetings on the internal working group pages (at -> log in to MyGDCh with membership number and password). The main tasks of the working group include:


  • Evaluation, further development and validation of analysis methods for the detection of pharmacologically active substances in animals, animal products and food with special attention to new analysis techniques
  • Elaboration of opinions on legally relevant and other processes with regard to residues of veterinary drugs and other pharmacologically active substances on behalf of the Food Chemical Society.

The results of the activity are primarily used in official examination tasks, in self-monitoring systems in food production and in the work of expert laboratories.

Head of the working group


Dipl.-Chem. Angelika Oltmanns
State investigation institute for the
Health and Veterinary Saxony
Department of Pharmacologically Active Substances
Zschopauer Str. 87
09111 Chemnitz
Tel .: 0351 8144-3653


Dr. Christian Hinkel
Bavarian State Office for Health
and food safety (LGL)

Term of office: 2021-2023

Evaluation and further development of methods

In the past few years numerous methods for the detection of natural and synthetic hormones, of antibiotic substances (including sulfonamides, tetracyclines, quinolones) and of anthelmintics have been worked on. With the cooperation of the working group , this methodical work has found its way into official investigation procedures. The working group regularly sifts through new, available analytical methods for the detection of pharmacologically active substances, the process characteristics of which make an application in testing laboratories appear practicable in compliance with the EU validation regulations. As a rule, checks for selectivity, sensitivity, precision and recovery are first carried out in at least three laboratories from the group of working groups on the basis of grown or spiked samples. The results are presented in the working group and discussed in detail. In the event of a successful pre-validation, the second step is to check the corresponding method with a larger number of participants from the group of active and corresponding members. The methods currently being worked on include the determination of:


  • Coccidiostats
    In comparative studies by different laboratories, experiences in the analysis of different matrices and modifications of the generally recognized method for the determination of coccidiostats with LC-MS-MS are evaluated.
  • ß-lactam antibiotics
    The active ingredients from the group of ß-lactam antibiotics can be determined very sensitively using the LC-MS-MS method. A method that has been extensively tested in the context of a dissertation (link) is tested with spiked samples with regard to its robustness for use in routine laboratories and its suitability for checking the maximum levels stipulated in food.
  • Aminoglycosides
    For the determination of aminoglycosides in biological matrices, the coupling of HPLC with a mass-selective detector (tandem MS) appears to be well suited. The comparative investigation of published analytical methods in several laboratories is currently being carried out.
  • Antibiotics in honey
    For the determination of antibiotics in honey using LC-MS-MS, various test methods were compared with regard to sample preparation. The following working hypotheses were formulated from the results of the internal laboratory comparison test "Veterinary medicinal products in honey":
    1.) When honey is normally stored at room temperature, anhydroerythromycin is formed from erythromycin through elimination of water.
    2.) A work-up process that does not contain an acidic hydrolysis step leads to sub-findings for sulfonamides and false negative results for Dapsone.
    3.) Macrolides are unstable in acidic solution.
    4.) An acidic environment promotes the epimerization of tetracyclines.
    5.) Influences of the pH value of the extraction agent used on the results of trimethoprim, nitroimidazoles, tylosin A, tylosin B, and chloramphenicol are not discernible.

Screening test systems

The working group has set itself the goal of following the new developments in rapid test systems in addition to checking physico-chemical measuring methods such as LC-MS. After an extensive comparison of the commercially available ELISA test kits, the premitest as a rapid antibiotic test in organ material was compared in several laboratories with the results of the three-plate inhibitor test and chemical analysis methods. The working group already has some experience with the use of optical biosensors in residue analysis, which will be further examined in the near future.

Validation of methods

The aim of the validation of examination methods includes the assurance of a scientifically justified and legally secured comparability of analysis results. The validation is part of quality assurance systems according to DIN EN ISO / IEC 17025.

The analysis results from different laboratories within the EU and beyond must be comparably accurate, correct and precise. Decision 2002/657 / EC (Literature 1) applies to test results in the context of official residue controls.

A sub-working group of the working group has developed a proposed procedure for the practical implementation of validation in routine laboratories in accordance with the above-mentioned EU decision. This was published after discussion in the working group (literature 2). In addition, a comparative analysis of various validation procedures was carried out.

The results of these discussions have found their way into the validation procedure recommended by the BVL using the "InterVal" software from quo data GmbH.

Links and literature




1) Commission decision of August 12, 2002 on the implementation of Council Directive 96/23 / EC on the implementation of analytical methods and the evaluation of results
(2002/657 / EG)
2) Validation of procedures for testing pharmacologically active substances in the routine laboratory
food chemistry 57, 99-102 (2003)
3) Discussion on the method validation of procedures for testing for pharmacologically active substances
food chemistry 58, 56-57 (2004)


Annual report 2020

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Comment on chloramphenicol ( pdf ) Poster LM-Tag 2014 ( pdf ) Rapid test methods ( pdf ) Laboratory tests on honey ( pdf )

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last modified: 24.11.2021 09:34 H from Webmaster