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- Aurofusarin (2)
- HPLC-FLD/DAD (2)
- Mycotoxins (2)
- Acrylamid (1)
- Column liquid chromatography-mass spectrometry (1)
- Correlation (1)
- Ergosterol (1)
- Fusarium-damaged kernels (1)
- Gas chromatography (1)
- Immunoaffinity column (1)
The aim of this study was to investigate the distribution of zearalenone in wheat kernels contaminated with this mycotoxin. Kernels from a sample of a wheat harvest affected by Fusarium culmorum were sorted into six groups according to their visual attributes. Milled portions of these groups were analysed by high-performance liquid chromatography with fluorescence and diode array detection. The clean-up was performed with an immunoaffinity column after methanol/water (4:1, v/v) extraction. The zearalenone content of the unsorted kernel fraction was 74 µg/kg. The group of healthy-looking kernels was contaminated with only 6 µg/kg of zearalenone. The groups of kernels that appeared shrunken and chalky white, damage routinely caused by Fusarium, were contaminated with 170 and 117 µg/kg, respectively. A remarkably high level of zearalenone contamination, 2,184 µg/kg, was observed for the group of reddish kernels. An association between the presence of the red pigment aurofusarin and high levels of zearalenone was found. Therefore, this pigment may be used as a marker of high zearalenone content.
Distribution of Trichothecenes, Zearalenone, and Ergosterol in a Fractionated Wheat Harvest Lot
(2008)
To investigate possible co-occurrences of type B trichothecenes and zearalenone within a Fusarium culmorum-infected wheat harvest lot, kernels were fractionated into six groups by visual criteria. The Fusarium-damaged kernels were subdivided into white, shrunken, and red kernel groups, and the remaining kernels were sorted into healthy, black spotted, and nonspecific groups. The distribution patterns of nivalenol, deoxynivalenol, zearalenone, and ergosterol were determined for possible correlations. Significant correlations between the distribution patterns were found for the mycotoxins and ergosterol for the grouped kernels (r = 0.997-0.999, p < 0.0001). Additionally, remarkably outstanding levels of nivalenol (24-fold more than the mean at 1.16 mg/kg), deoxynivalenol (27-fold more than the mean at 0.16 mg/kg), zearalenone (25-fold more than the mean at 77 µg/kg), and ergosterol (17-fold more than the mean at 13.4 mg/kg) were found in the red kernel group. Further, detailed mycotoxin and ergosterol analyses were carried out on various segments (kernel surface, conidia, bran, and flour) of the red kernels. However, the mycotoxin and ergosterol distribution profiles revealed nonsignificant correlations for these kernel segments, with the exception of deoxynivalenol and nivalenol, which were moderately correlated (r = 0.948, p = 0.035).
High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) can be used for simultaneous quantification of various mycotoxins in contaminated food samples. Therefore, multi-mycotoxin methods have been developed in the last couple of years. To enlarge these methods for further analytes, we have developed a LC-MS/MS method for the quantification of the mycotoxin aurofusarin. Additionally, further LC-MSn experiments were performed to demonstrate the fragmentation pattern of aurofusarin. Applicable multiple reaction monitoring (MRM) transitions of aurofusarin were found and optimized by parameter variation of the tandem mass spectrometer. The applicability of the developed method was tested by analysis of naturally contaminated wheat.
Liquid chromatography coupled with tandem mass spectrometric detection has gained more importance for mycotoxin determination in recent years. In addition to instrumental improvements, the development of LC-MS-MS has also been a consequence of the availability of stable isotope internal standards, e.g., 13C-labelled mycotoxins. Thus, the LC-ESI-MS-MS method using a 13C15-deoxynivalenol internal standard as a state-of-the-art technique was selected as a reference procedure for an in-house method comparison study of the determination of deoxynivalenol (DON) in wheat materials. Alternative methods include LC-diode array detection, which is a frequently used routine procedure for DON-analysis, and gas chromatography after trimethylsilylation. For GC application, an electron capture detector and a negative chemical ionisation mass spectrometry detector were used, which have both been well described in the literature. The method comparison was conducted using t test statistics. Additionally, this study also calculates important method performance characteristics, including accuracy, linearity, limit of detection, limit of quantification, recovery, and variation coefficient. Furthermore, this is the first report of a GC-MS method for the determination of DON using a fully carbon-labelled 13C15-DON as an IS. The GC-MS using 13C15-DON as an IS has produced comparable results to the 13C-IS-LC-MS-MS reference method with a similar sensitivity. ECD detection was slightly less sensitive, but is also suited for DON analysis in wheat. Due to the high LOQ, the LC-DAD method seems highly applicable to the measurement of highly contaminated samples.