Purity assessment of commercially available crystalline deoxynivalenol.
Deoxynivalenol (DON) obtained from 2 commercial sources was characterized, and its purity was determined. The structural identity of DON was confirmed by 1H and 13C-nuclear magnetic resonance (NMR) spectroscopy, gas chromatography with mass spectrometric (GC/MS) detection, and infrared/attenuated total reflectance (IR/ATR) spectroscopy. NMR spectra showed shifts that varied from previously published data. However, we established a complete, unambiguous assignment for all signals. Chromatograms obtained by GC/MS were almost identical for both investigated samples and confirmed the structure of DON. Likewise, IR/ATR spectra verified the identity of DON. The degree of purity was determined by liquid chromatography (LC) with a variable wavelength detector, LC/MS/MS, GC with electron-capture detection (GC-ECD), and ultraviolet (UV) spectrophotometry. The purity check using LC showed a single peak in both chromatograms. With LC/MS/MS measurements, we could detect small amounts of impurities in the crystalline DON from both sources. In data obtained by GC-ECD, no differences in purity were observed. The UV measurements showed an absorption maximum at 217 nm. The mean epsilon(m) of the extinction coefficients was calculated as 6727 (L/cm/mol) for DON (Sigma) and 6825 (L/cm/mol) for DON (Biopure). Finally, the purity of DON from the 2 commercial sources was calculated as >96 and >98%, respectively. Although the DON produced by both providers can be considered sufficiently pure for routine analysis of trichothecenes in food and feed, this work again demonstrated that the impurity of the solid mycotoxin constitutes the greatest contribution to the overall uncertainty of a mycotoxin calibrant.
Krska
Rudolf
R
Institute for Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, Konrad Lorenz Str, Tulln, Austria. rudolf.krska@boku.ac.at
Szente
Elisabeth
E
Freudenschuss
Martin
M
Hametner
Christian
C
Zöllner
Peter
P
D002853:Chromatography, Liquid; D003460:Crystallization; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D012015:Reference Standards; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014255:Trichothecenes / Q000032:analysis* / Q000302:isolation & purification
D007202:Indicators and Reagents; D014255:Trichothecenes; C007262:deoxynivalenol