Fachbereich Veterinärmedizin



    Determination of ochratoxin A in grains by immuno-ultrafiltration and HPLC-fluorescence detection after postcolumn derivatisation in an electrochemical cell (2011)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Reiter, Elisabeth Viktoria
    Cichna-Markl, Margit
    Chung, Duck-Hwa
    Shim, Won-Bo
    Zentek, Jürgen
    Razzazi-Fazeli, Ebrahim
    Analytical and bioanalytical chemistry; 400(8) — S. 2615–2622
    ISSN: 1618-2642
    DOI: 10.1007/s00216-011-4942-2
    Pubmed: 21461614
    Institut für Tierernährung

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    Gebäude 8
    14195 Berlin
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    Abstract / Zusammenfassung

    The paper presents a new sample clean-up method based on immuno-ultrafiltration for the analysis of ochratoxin A in cereals. In contrast to immunoaffinity chromatography, in immuno-ultrafiltration, the antibodies are used in non-immobilised form. Ochratoxin A was extracted with ACN/water (60/40, v/v), and the extract was loaded onto the ultrafiltration device. After a washing step with phosphate-buffered saline, containing 0.05% Tween 20, ochratoxin A was eluted with MeOH/acetic acid (99/1, v/v). The detection of ochratoxin A was carried out with high-performance liquid chromatography and a fluorescence detector coupled to an electrochemical cell (Coring cell). The electrochemical cell was used to eliminate matrix interferences by oxidising matrix compounds. The method was validated by repeatedly analysing spiked barley and rye samples as well as a certified wheat reference material. Recoveries and standard deviations (1 SD) were found to be 71 ± 9%, 77 ± 12% and 77 ± 8% in wheat, barley and rye, respectively. The limit of detection (S/N = 3) and limit of quantitation (S/N = 10) were determined to be 0.4 μg kg(-1) and 1 μg kg(-1). The analysis of the certified reference material resulted in ochratoxin A concentrations which were in the range assigned by the producer. Additionally, the effect of the electrochemical cell on other widely used clean-up techniques, namely the immunoaffinity clean-up and multifunctional columns (Mycosep #229), was evaluated. In all clean-up methods, an improvement of the chromatogram quality was registered.