Validation of an analytical method for the determination of carbadox and olaquindox in feedstuff by liquid chromatography coupled to UV and/or diode array detection

Abstract

The performance characteristics of an analytical method based on high-performance liquid chromatography (HPLC) for the detection of the banned growth promoters, carbadox and olaquindox, in feedstuff were determined via a collaborative study. The relative standard deviation of repeatability (RSD_r) ranged 1.1–5.5% for carbadox and 2.5–6.2% for olaquindox. The relative standard deviation of reproducibility (RSD_R) ranged 6.4–10.7% for carbadox and 12.8-20.0% for olaquindox. In all cases, the HORRAT values were equal or below the critical value of 1.5. Moreover, trueness in all cases was between the acceptance limits of 80 and 110%. Consequently, it was concluded that the method is suitable for quantitative evaluation. The method was also qualitatively assessed in terms of correct identification of the target analytes by examination of the UV spectrum when the more specific diode array detector was coupled to HPLC. In all cases, the percentage of correct identifications was ≥94% for olaquindox and carbadox, while the percentage of false negatives was ≤6%, suggesting the extended utilization of the HPLC method from quantitative to confirmatory status with a diode array detector.

Keywords:

• HPLC-UV
• HPLC-diode array detection
• validation study
• growth promoters
• feedstuff
• olaquindox
• carbadox

Acknowledgements

The authors would like to thank the participating institutes: Agriculture Research Centre (Gembloux, Belgium), COVAX-VESELY (Praha, Czech Republic), KTTK (Vantaa, Finland), DGCCRF-L35 (Rennes, France), Sächsische Landesanstalt für Landwirtschaft (Leipzig, Germany), Bayerisches Landesamt für Gesundheid und Lebensmittelsi-cherheit (Oberschleissheim, Germany), LUFA-ITL (Kiel, Germany), LUFA Department of Microbiology (Speyer, Germany), National Institute of Agriculture Quality Control–Central Laboratory (Budapest, Hungary), State Laboratory (Dublin, Ireland), Istit. Zoo. Sper. Lombardia E. Romagna r. Bromat. Feeds Lab. (Brescia, Italy), RMIZS (Roma, Italy), AGES (Wien, Österreich), EZN INIAP (Vale de Santarem, Portugal), DIN (Sta. Comba Dao, Portugal), LNIV Food Chemistry and Toxicology Head Unit (Lisbon, Portugal), Central Control and Testing Institute of Agriculture (Bratislava, Slovakia), Laboratoria Arbitral Agro. MAPA (Aravaca–Madrid, Spain), Lab. Agroalimentari Gen. Catalunya (Vilassar de Mar–Barcelona, Spain), SVA (Uppsala, Sweden) and RIKILT (Wageningen, The Netherlands). The SIMBAG-FEED project is funded by EC, DG RTD, 5th Framework Programme, Competitive and Sustainable Growth (GROWTH) Programme, Measurements and Testing generic activity, Contract no. G6RD-CT-2000-00413. We are also very grateful to Gerard Kramer and Håkan Emteborg (both IRMM) for the test samples prepared and utilised in the present study.