Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    A critical assessment of the performance criteria in confirmatory analysis for veterinary drug residue analysis using mass spectrometric detection in selected reaction monitoring mode
    Berendsen, Bjorn J.A. ; Meijer, Thijs ; Wegh, Robin ; Mol, Hans G.J. ; Smyth, Wesley G. ; Armstrong Hewitt, S. ; Ginkel, Leen van; Nielen, Michel W.F. - \ 2016
    Drug Testing and Analysis 8 (2016)5-6. - ISSN 1942-7603 - p. 477 - 490.
    confirmatory analysis - ion ratio - liquid chromatography - mass spectrometry - performance criteria

    Besides the identification point system to assure adequate set-up of instrumentation, European Commission Decision 2002/657/EC includes performance criteria regarding relative ion abundances in mass spectrometry and chromatographic retention time. In confirmatory analysis, the relative abundance of two product ions, acquired in selected reaction monitoring mode, the ion ratio should be within certain ranges for confirmation of the identity of a substance. The acceptable tolerance of the ion ratio varies with the relative abundance of the two product ions and for retention time, CD 2002/657/EC allows a tolerance of 5%. Because of rapid technical advances in analytical instruments and new approaches applied in the field of contaminant testing in food products (multi-compound and multi-class methods) a critical assessment of these criteria is justified. In this study a large number of representative, though challenging sample extracts were prepared, including muscle, urine, milk and liver, spiked with 100 registered and banned veterinary drugs at levels ranging from 0.5 to 100 µg/kg. These extracts were analysed using SRM mode using different chromatographic conditions and mass spectrometers from different vendors. In the initial study, robust data was collected using four different instrumental set-ups. Based on a unique and highly relevant data set, consisting of over 39 000 data points, the ion ratio and retention time criteria for applicability in confirmatory analysis were assessed. The outcomes were verified based on a collaborative trial including laboratories from all over the world. It was concluded that the ion ratio deviation is not related to the value of the ion ratio, but rather to the intensity of the lowest product ion. Therefore a fixed ion ratio deviation tolerance of 50% (relative) is proposed, which also is applicable for compounds present at sub-ppb levels or having poor ionisation efficiency. Furthermore, it was observed that retention time shifts, when using gradient elution, as is common practice nowadays, are mainly observed for early eluting compounds. Therefore a maximum retention time deviation of 0.2 min (absolute) is proposed. These findings should serve as input for discussions on the revision of currently applied criteria and the establishment of a new, globally accepted, criterion document for confirmatory analysis.

    Residue analysis of veterinary drugs and growth-promoting agents
    Stolker, A.A.M. ; Zuidema, T. ; Nielen, M.W.F. - \ 2007
    TrAC : Trends in Analytical Chemistry 26 (2007)10. - ISSN 0165-9936 - p. 967 - 979.
    tandem mass-spectrometry - performance liquid-chromatography - animal-food products - malachite green - antiinflammatory drugs - confirmatory analysis - leucomalachite green - nitrofuran residues - biological matrices - hair analysis
    Two major trends are observed in the analysis of veterinary drugs and growth-promoting agents. First is the selection of sample material for monitoring the use of registered veterinary drugs. Traditionally meat, kidney and liver were analyzed but, due to the food scandals in which meat was very often involved, the consumption of alternative products (e.g., eggs and fish) has become more popular and therefore more of interest for residue-monitoring programmes. Most food scandals started with contamination of animal feed, so feed has also gained interest for monitoring purposes. For the detection of unauthorized substances (e.g., growth-promoting agents), the matrix hair is frequently used because residues can be detected in hair even a long time after treatment. Second, the techniques used for residue analysis are moving from target-orientated methods, mainly based on liquid chromatography in combination with triple-quadrupole mass-spectrometric detection (LC-QqQ-MS), towards accurate mass full-scan MS techniques (e.g., time-of-flight (ToF)-MS and Fourier-transform(FT)-MS. Full-scan MS techniques enable retrospective analysis (i.e. without re-injecting the sample) and real multi-residue analysis (including different classes of veterinary drugs). The application of full-scan MS also has consequences for separation and extraction techniques, which have to be applicable to a broad range of compounds differing in physical and chemical properties. Experience shows that ToF-MS in combination with ultra-performance LC (UPLC) is very powerful for multi-residue analysis. The introduction of new MS techniques also has consequences for European Union (EU) criteria defined for confirmation of the identity of compounds. It is suggested that both mass-resolution and mass-accuracy data influence identity confirmation and both parameters should be implemented in the revision of European Commission Decision 2002/657/EC. (C) 2007 Elsevier Ltd. All rights reserved.
    The ultimate veal calf reference experiment: Hormone residue analysis data obtained by gas and liquid chromatography tandem mass spectrometry
    Nielen, M.W.F. ; Lasaroms, J.J.P. ; Essers, M.L. ; Sanders, M.B. ; Heskamp, H.H. ; Bovee, T.F.H. ; Rhijn, J.A. van; Groot, M.J. - \ 2007
    Analytica Chimica Acta 586 (2007)1-2. - ISSN 0003-2670 - p. 30 - 34.
    yeast estrogen bioassay - confirmatory analysis - bovine urine - boldenone - steroids - cattle - calves - feces - androsta-1,4-diene-3,17-dione - 17-alpha-boldenone
    A lifetime controlled reference experiment has been performed using 42 veal calves, 21 males and 21 females which were fed and housed according to European regulations and common veterinary practice. During the experiment feed, water, urine and hair were sampled and feed intake and growth were monitored. Thus for the first time residue analysis data were obtained from guaranteed lifetime-untreated animals. The analysis was focused on the natural hormones estradiol and testosterone and their metabolites, on 17 beta- and 17 alpha-nortestosterone, on 17 beta- and 17 alpha-boldenone and androsta-1,4-diene-3,17-dione (ADD), and carried out by gas chromatography tandem mass spectrometry (GC/MS/MS), an estrogen bioassay and liquid chromatography (LC) MS/MS. Feed, water and hair samples were negative for the residues tested. Female calf urines showed occasionally low levels of 17 alpha-estradiol and 17 alpha-testosterone. On one particular sampling day male veal calf urines showed very high levels of 17 alpha-testosterone (up to 1000 ng mL(-1)), accompanied by lower levels of estrone and 17 beta-testosterone. Despite these extreme levels of natural testosterone, 17 beta-boldenone was never detected in the same urine samples; even 17 alpha-boldenone and ADD were only occasionally beyond CC alpha (maximum levels 2.7 ng ng mL(-1)). The data from this unique experiment provide a set of reference values for steroid hormones in calf urine and demonstrate that 17 beta-boldenone is not a naturally occurring compound in urine samples. (c) 2006 Elsevier B.V. All rights reserved.
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