Feasibility study for the production of certified calibrants for the determination of deoxynivalenol and other B-trichothecenes: intercomparison study.
Thirteen European laboratories experienced in the analysis of mycotoxins participated in an intercomparison study within a European Commission-funded project. Goals of the study were to check the fitness for purpose of a small batch of gravimetrically prepared calibrants; to compare individually prepared calibrants with common calibrants; to check the feasibility of toxin mixtures as calibrant solutions; and to give recommendations on the production of future certified reference materials (CRMs) with regard to the nature of the calibrant and the means of certification. Each laboratory received ampules of each common calibrant containing single toxins [solution containing either deoxynivalenol (DON), 3-acetyl-DON (3-Ac-DON), nivalenol (NIV), or 15-acetyl-DON (15-Ac-DON)] and 3 ampules of toxin-mixture (solutions of DON + 3-Ac-DON + NIV in acetonitrile) of known concentrations (about 20 microg/mL). Ampules with single toxins (solution containing either DON, 3-Ac-DON, NIV, or 15-Ac-DON) and a toxin-mixture (solutions of DON + 3-Ac-DON + NIV in acetonitrile) of unknown concentrations were distributed to the participants for quantification. The participating laboratories used mainly high-performance liquid chromatography (HPLC)-diode array detection UV for DON, 3-Ac-DON, NIV, and 15-Ac-DON; gas chromatography-electron capture detection (GC-ECD) and GC-mass spectrometry methods were used sparingly. Linear calibration curves were achieved by >90% of the participants. Relative between-day variation (RSDr) of 26% of the laboratories was greater than the target value of 5% for HPLC, and RSDr of 32% of the laboratories was greater than the desired value of 10% for GC. Relative between-laboratory variation (RSDR) of the GC results obtained with single common calibrants was greater than the target value of 16% for all laboratories. RSDR of the HPLC results for the common unknown single toxin solutions was less than the target value of 8% except for 15-Ac-DON. Generally, better recoveries were observed from common calibrants (102% for mix calibrants and 98% for single calibrants) than from individually prepared calibrants (95%). This international comparison study clearly showed the high scattering of results in the analysis of type-B trichothecenes, particularly when GC was used. Obviously, this intercomparison study was not suited for the certification of B-trichothecenes. A certification of the proposed calibrant material was therefore recommended on the basis of its gravimetrical preparation.
Krska
Rudolf
R
University of Natural Resources and Applied Life Sciences, Center for Analytical Chemistry, Department for Agrobiotechnology, IFA-Tulln, Vienna, Konrad Lorenz Strasse 20, A-3430 Tulln, Austria. rudolf.krska@boku.ac.at
Welzig
Elvira
E
Drs
Elisabeth
E
Josephs
Ralf D
RD
Schothorst
Ronald C
RC
Van Egmond
Hans P
HP
Pettersson
Hans
H
Chan
Danny
D
MacDonald
Susan
S
D002138:Calibration / Q000592:standards*; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet; D014255:Trichothecenes / Q000032:analysis*
D007202:Indicators and Reagents; D014255:Trichothecenes; C007262:deoxynivalenol