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rac-2,3-Dibromopropionamide
(2013)
The racemic title compound, C3H5Br2NO, was crystallized from methanol. In the crystal, adjacent molecules are linked through N–H···O hydrogen bonds, forming chains along the c-axis direction. These chains are linked through N–H···O hydrogen bonds, forming an undulating two-dimensional network lying parallel to the bc plane. There are also short Br···Br contacts present [3.514 (3) Å].
Deoxynivalenol (DON) is one of the most abundant mycotoxins contaminating food and feed worldwide. Upon absorption, the major portion of the toxin is excreted by humans and animal species as glucuronide. However, consistent in vitro data on DON glucuronidation are lacking. In the present study, the metabolism of DON was investigated using liver microsomes from humans and six different animal species. It was shown that all animal and human liver microsomes led to the formation of up to three different mono-O-glucuronides with significant interspecies differences. While the activity of human liver microsomes was low (0.8 to 2.2 pmol·min–1·mg–1), bovine liver and rat liver microsomes conjugated DON with activities of 525 pmol·min–1·mg–1 and 80 pmol·min–1·mg–1, respectively.
Ergotaminine
(2012)
The title compound {systematic name: (6aR,9S)-N-[(2R,5S,10aS,10bS)-5-benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-8H-oxazolo[3,2-a]pyrrolo[2,1-c]pyrazin-2-yl]-7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3-fg]quinoline-9-carboxamide}, C33H35N5O5, was formed by an epimerization reaction of ergotamine. The non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar [maximum deviation = 0.317 (4) Å] and shows an envelope conformation, whereas ring D, involved in an intramolecular N–H···N hydrogen bond exhibits a slightly distorted chair conformation. The structure displays chains running approximately parallel to the diagonal of bc plane that are formed through N–H···O hydrogen bonds.
The title compound, also known as cis-zearalenone (cis-ZEN), C18H22O5, has already been reported elsewhere [Griffin et al. (1981). ACA Ser. 29, 35], but no atomic coordinates are publicly available. The molecule is of interest with respect to its toxicity. In the crystal, intramolecular O—H···O hydrogen bonds stabilize the molecular conformation, while intermolecular O—H···O hydrogen bonds link the molecules to form infinite chains along the [110] and [1¯10] directions. The absolute configuration has been assigned by reference to an unchanging chiral centre in the synthetic procedure.
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.
A method has been derived to completely recover mineral oil dispersed in water. The method involves three steps: the emulsification of the mineral oil by adding amphiphiles, the breaking of the emulsion by adding salts and the extraction of the mineral oil by a non-polar aprotic solvent. Various amphiphiles and types and concentrations of salts were tested. By using amphiphiles with HLB numbers in the range 4.7 to 40 a complete recovery of the mineral oil could be obtained for a combination of salts Na2SO4 + NaH2PO4 with total ionic strength of 6 mol/L.
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.
The 2-year international joint project HYCREF (Contract-No. G6RD-CT-2002-00854), funded by the European Commission in the 5th Framework programme, aimed to develop methods to prepare homogenous and stable water-, soil- and waste reference materials contaminated with mineral oil hydrocarbons and to test certify the mineral oil content by gas chromatographic methods. As mineral oil products are important sources for environmental contaminations, appropriate reference materials certified by using the new gas chromatographic methods (soil: ISO/FDIS 16703, waste: prEN 14039 and KW/04, water: ISO 9377-2) are highly needed. Additional to the HYCREF-results presented in part Imineral contaminated soilsthis second paper gives an overview of the feasibility study for the preparation and test certification of three waste reference materials (offshore marine sediment, building material and industrial waste). The following specifications, which had been defined in the project work plan, were reached successfully: uncertainty of the mineral oil content resulting from the certification exercise ≤ 5% and a between-bottle inhomogeneity of ≤ 3%. All three materials have been evaluated for long- and short term stability. They contain different levels and types of mineral oil and cover the full application range of ISO/FDIS 16703 and prEN 14039 (10010,000 mg/kg). The expanded uncertainties U cert of the three materials are about 6%. In this way, they are comparable to ERM®-CC015a (U cert=7.1%, mineral oil in a river sediment) and are suited to close the present gap of commercially available CRM for mineral oil determination in waste.