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- Quality assurance (5)
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- Deoxynivalenol (3)
- Nivalenol (3)
- Zearalenone (3)
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- Claviceps purpurea (2)
- Epimerization (2)
- Food analysis (2)
Organisationseinheit der BAM
Deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) are toxic secondary metabolites produced by several species of Fusarium fungi. These mycotoxins are often found together in a large variety of cereal-based foods, which are regulated by maximum content levels of DON and ZEN. To date, suitable certified reference materials (CRM) intended for quality control purposes are lacking for these Fusarium mycotoxins. In order to overcome this lack, the first CRM for the determination of DON, NIV and ZEN in naturally contaminated wheat flour (ERM®-BC600) was developed in the framework of a European Reference Materials (ERM®) project. This article describes and discusses the whole process of ERM®-BC600 development, including material preparation, homogeneity and stability studies, and an interlaboratory comparison study for certification. A total of 21 selected expert laboratories from different European countries with documented expertise in the field of mycotoxin analysis took part in the certification study using various gas and liquid chromatographic methods. The certified values and their corresponding expanded uncertainties (k=2) were assigned in full compliance with the requirements of ISO Guide 35 and are as follows: 102±11 µgkg-1 for DON, 1000±130 µgkg-1 for NIV and 90±8 µgkg-1 for ZEN.
Die zuverlässige Überwachung geltender Mykotoxin-Grenzwerte ist elementarer Bestandteil von Lebensmittelsicherheit und Verbraucherschutz. Durch die zunehmende Bedeutung der Qualitätssicherung ist auch die Nachfrage an zertifizierten Referenzmaterialien (ZRM) in den letzten Jahren deutlich gestiegen. Dem steht derzeit jedoch nur eine sehr begrenzte Auswahl geeigneter ZRM gegenüber.
Mycotoxins are important non-anthropogenic food and feed contaminants, which can be present on almost every agricultural commodity. Effective consumer protection therefore essentially depends on food surveillance by reliable quantitative analysis enabled by appropriate quality control. Certified (matrix) reference materials (CRMs) are versatile tools to support Quality assurance. However, in the case of ochratoxin A (OTA), a hepato- and nephrotoxic mycotoxin, which is regulated in various foods, there is a lack of suitable CRMs. This lack has now been overcome by the development of two European Reference Materials (ERM®) for the Determination of OTA in roasted coffee (ERM®-BD475) and red wine (ERM®-BD476). This article discusses the material preparation process as well as the results of homogeneity and stability testing. Furthermore, the results of the inhouse certification studies carried out at BAM Federal Institute for Materials Research and Testing are presented and discussed. Interlaboratory comparison studies involving selected expert laboratories with documented Expertise in the field of mycotoxin analysis were conducted to confirm the certified values determined by BAM. The certified ochratoxin A values and their corresponding expanded uncertainties (k = 2) were assigned in full compliance with the requirements of ISO Guide 35 and are as follows:
(6.0 ± 0.6) µg kg-1 for roasted coffee, ERM®-BD475, and (0.52 ± 0.11) µg L-1 for red wine, ERM®-BD476.
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].
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.
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.
Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na+-SCX) was developed to quantitate 12 priority ergot alkaloids in rye flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80–120% (rye flour) and 71–96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 µg kg1 per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 rye flours (max 178 ± 5 µg kg1) and, reported for the first time, 7 wheat germ oils (max 56.8 ± 2.7 µg kg1) expressed as the sum of 12 ergot alkaloids.