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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    Current issues involving screening and identification of chemical contaminants in foods by mass spectrometry
    Lehotay, S.J. ; Sapozhnikova, Y. ; Mol, J.G.J. - \ 2015
    TrAC : Trends in Analytical Chemistry 69 (2015). - ISSN 0165-9936 - p. 62 - 75.
    performance liquid-chromatography - pesticide-residue analysis - ion mobility spectrometry - information-dependent acquisition - pressure desorption ionization - supersonic molecular-beams - veterinary drug residues - flow-injection analysis - gas-chromatography
    Although quantitative analytical methods must be empirically validated prior to their use in a variety of applications, including regulatory monitoring of chemical adulterants in foods, validation of qualitative method performance for the analytes and matrices of interest is frequently ignored, or general guidelines are assumed to be true for specific situations. Just as in the case of quantitative method validation, acceptable method performance criteria should be established for qualitative analysis purposes to suit the analytical needs for given applications, and empirical method validation should be conducted to demonstrate the qualitative performance capabilities the method. This critical review article is intended to describe and discuss recent developments with of respect to qualitative aspects in mass spectrometry, and to make recommendations for validation of qualitative methods that meet common needs for monitoring of chemical contaminants in foods.
    The assessment of selectivity in different quadrupole-orbitrap mass spectrometry acquisition
    Berendsen, B.J.A. ; Wegh, R.S. ; Meijer, T. ; Nielen, M.W.F. - \ 2015
    Journal of the American Society for Mass Spectrometry 26 (2015)2. - ISSN 1044-0305 - p. 337 - 346.
    performance liquid-chromatography - veterinary drugs - confirmation - metabolites - residues - plasma - food - meat
    Selectivity of the confirmation of identity in liquid chromatography (tandem) mass spectrometry using Q-Orbitrap instrumentation was assessed using different acquisition modes based on a representative experimental data set constructed from 108 samples, including six different matrix extracts and containing over 100 analytes each. Single stage full scan, all ion fragmentation, and product ion scanning were applied. By generating reconstructed ion chromatograms using unit mass window in targeted MS(2), selected reaction monitoring (SRM), regularly applied using triple-quadrupole instruments, was mimicked. This facilitated the comparison of single stage full scan, all ion fragmentation, (mimicked) SRM, and product ion scanning applying a mass window down to 1 ppm. Single factor Analysis of Variance was carried out on the variance (s(2)) of the mass error to determine which factors and interactions are significant parameters with respect to selectivity. We conclude that selectivity is related to the target compound (mainly the mass defect), the matrix, sample clean-up, concentration, and mass resolution. Selectivity of the different instrumental configurations was quantified by counting the number of interfering peaks observed in the chromatograms. We conclude that precursor ion selection significantly contributes to selectivity: monitoring of a single product ion at high mass accuracy with a 1 Da precursor ion window proved to be equally selective or better to monitoring two transition products in mimicked SRM. In contrast, monitoring a single fragment in all ion fragmentation mode results in significantly lower selectivity versus mimicked SRM. After a thorough inter-laboratory evaluation study, the results of this study can be used for a critical reassessment of the current identification points system and contribute to the next generation of evidence-based and robust performance criteria in residue analysis and sports doping.
    Ultratrace LC-MS/MS Analysis of Segmented Calf Hair for Retrospective Assessment of Time of Clenbuterol Administration in Agriforensics
    Duvivier, W.F. ; Beek, T.A. van; Meijer, T. ; Peeters, R.J.P. ; Groot, M.J. ; Sterk, S.S. ; Nielen, M.W.F. - \ 2015
    Journal of Agricultural and Food Chemistry 63 (2015)2. - ISSN 0021-8561 - p. 493 - 499.
    tandem mass-spectrometry - performance liquid-chromatography - beta-agonist residues - equine hair - bovine hair - human urine - cattle - calves - contamination - samples
    In agriforensics, time of administration is often debated when illegal drug residues, such as clenbuterol, are found in frequently traded cattle. In this proof-of-concept work, the feasibility of obtaining retrospective timeline information from segmented calf tail hair analyses has been studied. First, an ultraperformance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) hair analysis method was adapted to accommodate smaller sample sizes and in-house validated. Then, longitudinal 1 cm segments of calf tail hair were analyzed to obtain clenbuterol concentration profiles. The profiles found were in good agreement with calculated, theoretical positions of the clenbuterol residues along the hair. Following assessment of the average growth rate of calf tail hair, time of clenbuterol administration could be retrospectively determined from segmented hair analysis data. The data from the initial animal treatment study (n = 2) suggest that time of treatment can be retrospectively estimated with an error of 3–17 days.
    Presence of the neurotoxin BMAA in aquatic ecosystems: What do we really know?
    Faassen, E.J. - \ 2014
    Toxins 6 (2014)3. - ISSN 2072-6651 - p. 1109 - 1138.
    methylamino-l-alanine - amyotrophic-lateral-sclerosis - performance liquid-chromatography - tandem mass-spectrometry - solid-phase extraction - amino-acid bmaa - cyanobacterial neurotoxin - neurodegenerative disease - 2,4-diaminobutyric acid - environmental-sample
    The neurotoxin ß-N-methylamino-L-alanine (BMAA) is suspected to play a role in the neurological diseases amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. BMAA production by cyanobacteria has been reported and contact with cyanobacteria infested waters or consumption of aquatic organisms are possible pathways to human exposure. However, there is little consensus regarding whether BMAA is present in cyanobacteria or not, and if so, at what concentrations. The aim of this review is to indicate the current state of knowledge on the presence of BMAA in aquatic ecosystems. Some studies have convincingly shown that BMAA can be present in aquatic samples at the µg/g dry weight level, which is around the detection limit of some equally credible studies in which no BMAA was detected. However, for the majority of the reviewed articles, it was unclear whether BMAA was correctly identified, either because inadequate analytical methods were used, or because poor reporting of analyses made it impossible to verify the results. Poor analysis, reporting and prolific errors have shaken the foundations of BMAA research. First steps towards estimation of human BMAA exposure are to develop and use selective, inter-laboratory validated methods and to correctly report the analytical work.
    Polyelectrolyte coatings prevent interferences from charged nanoparticles in SPME speciation analysis
    Zielinska, K. ; Leeuwen, H.P. van - \ 2014
    Analytica Chimica Acta 844 (2014). - ISSN 0003-2670 - p. 44 - 47.
    solid-phase microextraction - performance liquid-chromatography - surface modification - sample preparation - triclosan - fibers
    In this work we present a new approach for protection of the fiber in solid phase microextraction (SPME) from interfering charged particles present in the sample medium. It involves coating of commercial poly(dimethylsiloxane) extraction phase with polyelectrolyte layer composed of poly(diallyldimethylammonium chloride), and poly(sodium 4-styrenesulfonate). The modified fiber provides reproducible, convenient and fast extraction capabilities toward the model analyte, triclosan (TCS). A negatively charged polyelectrolyte coating prevents sorbing oxidic nanoparticles from both partitioning into the PDMS phase and aggregation at its surface. The results for the TCS/nanoparticle sample show that the polyelectrolyte layer-modified solid phase extracts just the free form of the organic compound and enables dynamic speciation analysis of the nanoparticulate target analyte complex.
    Quantitation of Maillard reaction products in commercially available pet foods
    Rooijen, C. van; Bosch, G. ; Poel, A.F.B. van der; Wierenga, P.A. ; Alexander, L. ; Hendriks, W.H. - \ 2014
    Journal of Agricultural and Food Chemistry 62 (2014)35. - ISSN 0021-8561 - p. 8883 - 8891.
    performance liquid-chromatography - advanced glycation endproducts - infant milk formulas - nutritive-value - furfural compounds - canine diets - breast-milk - lysine - proteins - furosine
    During processing of pet food, the Maillard reaction occurs, which reduces the bioavailability of essential amino acids such as lysine and results in the formation of advanced Maillard reaction products (MRPs). The aim of this study was to quantitate MRPs (fructoselysine (FL), carboxymethyllysine (CML), hydroxymethylfurfural (HMF)) and the cross-link lysinoalanine (LAL) in commercial pet foods. Sixty-seven extruded, canned, and pelleted dog and cat foods for growth and maintenance were analyzed using UPLC-MS. Canned pet foods contained on average the most FL, CML, and HMF (4534, 37, and 1417 mg/kg dry matter, respectively) followed by pelleted and extruded foods. Average daily intake (mg/kg body weight0.75) of HMF is 122 times higher for dogs and 38 times higher for cats than average intake for adult humans. As commercial pet foods are most often the only source of food for dogs and cats, future research focus should be on the bioavailability and long-term health implications of MRP consumption by dogs and cats.
    Targeted metabolite profile of food bioactive compounds by Orbitrap high resolution mass spectrometry: The 'FancyTiles' approach
    Troise, A.D. ; Ferracane, R. ; Palermo, M. ; Fogliano, V. - \ 2014
    Food Research International 63 (2014). - ISSN 0963-9969 - p. 139 - 146.
    virgin olive oil - cynara-scolymus l. - performance liquid-chromatography - artichoke leaf extract - time-of-flight - phenolic-compounds - sesquiterpene lactones - biological-activities - antioxidant capacity - sensory properties
    In this paper a new targeted metabolic profile approach using Orbitrap high resolution mass spectrometry was described. For each foodmatrix various classes of bioactive compounds and some specificmetabolites of interest were selected on the basis of the existing knowledge creating an easy-to-read fingerprinting named “FancyTiles”. The procedure resulted in a plot of semi-quantitative data allowed to highlight for each food the main metabolites related to the biological or sensorial attributes within an educated schema. Results showed that the FancyTile procedure is a useful tool for research programs aiming at improving the health potential of food and ingredients. In this paper the FancyTilewas described and it was successfully applied to verify the differences in themetabolic profile. Olive oils from different cultivars,waste millwaters fromolive grown in different location and artichokes cultivated with different agronomical practices were used as case study.
    Chemical Composition, Sensory Properties, Provenance, and Bioactivity of Fruit Juices as Assessed bij Chemometrics: A Critical Review and Guideline
    Ziekinski, A.F. ; Haminiuk, C.W.I. ; Nunes, C.A. ; Schnitzler, E. ; Ruth, S.M. van; Granato, D. - \ 2014
    Comprehensive Reviews in Food Science and Food Safety 13 (2014)3. - ISSN 1541-4337 - p. 300 - 316.
    principal component analysis - near-infrared spectroscopy - performance liquid-chromatography - commercial grape juices - antioxidant activity - consumer segmentation - geographical origin - electronic tongue - phenolic content - orange juice
    The use of univariate, bivariate, and multivariate statistical techniques, such as analysis of variance, multiple comparisons of means, and linear correlations, has spread widely in the area of Food Science and Technology. However, the use of supervised and unsupervised statistical techniques (chemometrics) in order to analyze and model experimental data from physicochemical, sensory, metabolomics, quality control, nutritional, microbiological, and chemical assays in food research has gained more space. Therefore, we present here a manuscript with theoretical details, a critical analysis of published work, and a guideline for the reader to check and propose mathematical models of experimental results using the most promising supervised and unsupervised multivariate statistical techniques, namely: principal component analysis, hierarchical cluster analysis, linear discriminant analysis, partial least square regression, k-nearest neighbors, and soft independent modeling of class analogy. In addition, the overall features, advantages, and limitations of such statistical methods are presented and discussed. Published examples are focused on sensory, chemical, and antioxidant activity of a wide range of fruit juices consumed worldwide.
    Determination of T-2 and HT-2 toxins in food and feed: an update
    Krska, R. ; Malachova, A. ; Berthiller, F. ; Egmond, H.P. van - \ 2014
    World Mycotoxin Journal 7 (2014)2. - ISSN 1875-0710 - p. 131 - 142.
    tandem mass-spectrometry - performance liquid-chromatography - fusarium mycotoxin content - in-house validation - lc-ms/ms method - a trichothecenes - immunoaffinity cleanup - fluorescence detection - gas-chromatography - masked mycotoxins
    Based on the recent scientific opinion of the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain on the risks to human and animal health related to the presence of T-2 and HT-2 toxins in food and feed that was published by EFSA in the EFSA Journal, this article provides an update on the determination of these Fusarium mycotoxins. After a brief introduction into the chemistry of these toxins, both chromatographic and immuno-analytical methods are discussed for the determination of these type A trichothecenes. During the last decade, liquid chromatography with (tandem) mass spectrometry has become the most frequently used method for the determination of T-2 and HT-2 toxins, often within a multi-analyte approach. However, complex matrices and the resulting signal suppression effects, as observed particularly in electrospray-mass spectrometry methods owing to matrix effects, may require careful optimisation of clean-up, usage of matrix matched standards, or e.g. the use of internal standards. For specific purposes where extremely low limits of quantification are needed, e.g. for the analysis of duplicate diets, a dedicated gas chromatography method with multistage mass spectrometry has become available. Other novel analytical approaches to determine T-2 and HT-2 toxins in food and feed include biosensor-based methods in surface plasmon resonance and electrochemical formats, as well as DNA microchip assays. For rapid screening, several immunochemical methods (mostly ELISAs) have become available and some are sold as commercial test kits. Whereas these methods work fast, cross-reactivities with other trichothecenes can have an undesired effect on their accuracy. While proficiency tests including T-2 and HT-2 toxins have been carried out, none of the chromatographic or immunochemical methods have been formally validated in interlaboratory validation studies. There are no certified reference materials available for T-2 and HT-2 toxins.
    Analysis of pesticide residues in strawberries and soils by GC-MS/MS, LC-MS/MS and two-dimensional GC– time-of-flight MS comparing organic and integrated pest management farming
    Fernandes, V.C. ; Lehotay, S.J. ; Geis-Asteggiantec, L. ; Kwon, H. ; Mol, J.G.J. ; Kamp, H.J. van der; Mateus, N. ; Domingues, V.F. ; Delerue-Matos, C. - \ 2014
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 31 (2014)2. - ISSN 1944-0049 - p. 262 - 270.
    pressure gas-chromatography - tandem mass-spectrometry - performance liquid-chromatography - quechers sample preparation - qualitative aspects - multiresidue method - vegetables - fruits - extraction - foods
    In this study, we analyzed 22 strawberry and soil samples after their collection over the course of 2 years to compare the residue profiles from organic farming to integrated pest management practices in Portugal. For sample preparation, we used the citrate-buffered version of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. We applied three different methods for analysis: (i) 27 pesticides were targeted using LC-MS/MS; (ii) 143 were targeted using low pressure GC - tandem mass spectrometry (LP-GC-MS/MS); and (iii) More than > 600 pesticides were screened in a targeted and untargeted approach using comprehensive, two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Comparison was made of the analyses using the different methods for the shared samples. The results were similar, thereby providing satisfactory confirmation of both similarly positive and negative findings. No pesticides were found in the organic-farmed samples. In samples from integrated pest management practices, 9 pesticides were determined and confirmed to be present ranging from 2 µg kg-1 for fluazifop-p-butyl to 50 µg kg-1 for fenpropathrin. Concentrations of residues in strawberries were less than European maximum residue limits.
    N -(carboxymethyl)lysine: A Review on Analytical Methods, Formation, and Occurrence in Processed Food, and Health Impact
    Nguyen, Ha T. ; Fels, H.J. van der; Boekel, M.A.J.S. van - \ 2014
    Food Reviews International 30 (2014)1. - ISSN 8755-9129 - p. 36 - 52.
    glycation end-products - n-epsilon-carboxymethyllysine - performance liquid-chromatography - community-dwelling women - maillard reaction - lipid-peroxidation - protein glycation - milk-products - treated foods - diet
    Foods are often heat processed and may contain advanced glycation end products (AGE). One of the most widely studied AGE is Ne-(carboxymethyl)lysine (CML); nevertheless, knowledge on dietary CML is fragmentary. This study aimed to review current scientific knowledge on analytical methods to determine CML contents in food, chemical pathways of CML formation in food, occurrence of CML in food, and health implications of dietary exposure to CML. Chemical analyses of CML in food products are carried out by immunochemical assays and instrumental methods, but the former method may interfere with the food matrix. CML is formed in food through various chemical pathways, depending on food ingredients and processing conditions. The compound is present in many cooked foods, with relatively high concentrations in carbohydrate- rich foods and dairy products. Dietary CML is very likely to impair human health, but full cause-effect evidence is not available yet. More studies on metabolic effects and impact of food-derived CML on human health should be performed. Food production should be optimized to minimize CML concentrations, while maintaining acceptable microbiological safety and organoleptic properties of the final food product. To this end, more insights into effects of food composition and processing conditions on CML formation are necessary.
    Investigation of the presence of prednisolone in bovine urine
    Rijke, E. de; Zoontjes, P.W. ; Samson, D. ; Oostra, S. ; Sterk, S.S. ; Ginkel, L.A. van - \ 2014
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 31 (2014)4. - ISSN 1944-0049 - p. 605 - 613.
    performance liquid-chromatography - synthetic corticosteroids - domestic livestock - mass-spectrometry - feces - metabolites - liver
    Over the past 2 years low levels of prednisolone have been reported in bovine urine by a number of laboratories in EU member states. Concentrations vary, but are reported to be below approximately 3 g/l. In 40% of bovine urine samples from the Dutch national control plan had concentrations of prednisolone between 0.112.04 g/l. In this study the mechanism of formation of prednisolone was investigated. In-vitro conversion of cortisol by bacteria from faeces and soil, bovine liver enzymes and stability at elevated temperatures were studied. In-vitro bovine liver S9 incubation experiments showed a significant 20% decrease of cortisol within 6 hours, and formation of prednisolone was observed from 0.2 g/l at t = 0 to 0.5 g/l at t = 6. Under the influence of faeces, the stability of cortisol in urine is reduced and cortisol breaks down within 50 h. Prednisolone is formed up to 4 g/l at 70C after 15 h. However, this decreases again to 0 after 50 h. With soil bacteria, a slower decrease of cortisol was observed, but slightly higher overall formation of prednisolone, up to 7 g/l at 20C. As opposed to incurred urine, in fortified urine incubated with faeces or soil bacteria no prednisolone was detected. This difference may be explained by the presence of natural corticosteroids in the incurred sample. With UPLC-QToF-MS experiments, in urine and water samples incubated with faeces, metabolites known from the literature could be (tentatively) identified as 20ß-hydroxy-prednisolone, cortisol-21-sulfate, oxydianiline, tetrahydrocortisone-3-glucuronide and cortexolone, but for all compounds except 20ß-hydroxy-prednisolone no standards were available for confirmation. Based on the results of this study and literature data, for regulatory purposes a threshold of 5 g/l for prednisolone in bovine urine is proposed. Findings of prednisolone in concentrations up to 5 g/l in bovine urine can, most likely, originate from other sources than illegal treatment with growth promoters.
    Sports doping: Emerging designer and therapeutic B2-agonists
    Fragkaki, A.G. ; Georgakopoulos, C. ; Sterk, S.S. ; Nielen, M.W.F. - \ 2013
    Clinica Chimica Acta 425 (2013). - ISSN 0009-8981 - p. 242 - 258.
    acting beta(2)-adrenoreceptor agonists - chromatography-mass spectrometry - molecularly imprinted polymers - obstructive pulmonary-disease - beta-adrenergic agonists - performance liquid-chromatography - 2-dimensional gas-chromatography - developed bronchodilati
    Beta2-adrenergic agonists, or ß2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of ß2-agonists is prohibited in sports by the World Anti-Doping Agency (WADA) due to claimed anabolic effects, and also, is prohibited as growth promoters in cattle fattening in the European Union. This paper reviews the last seven-year (2006-2012) literature concerning the development of novel ß2-agonists molecules either by modifying the molecule of known ß2-agonists or by introducing moieties producing indole-, adamantyl- or phenyl urea derivatives. New emerging ß2-agonists molecules for future therapeutic use are also presented, intending to emphasize their potential use for doping purposes or as growth promoters in the near future.
    Screening methods and recent developments in the detection of anticoccidials
    Huet, A.C. ; Bienenmann-Ploum, M.E. ; Vincent, U. ; Delahaut, P. - \ 2013
    Analytical and Bioanalytical Chemistry 405 (2013)24. - ISSN 1618-2642 - p. 7733 - 7751.
    tandem mass-spectrometry - performance liquid-chromatography - linked-immunosorbent-assay - time-resolved fluoroimmunoassay - fluorescence polarization immunoassay - uv spectrophotometric detection - antibody-based immunoassay - feed additive nicarbazin - chain v
    This article presents a review of the current trends in the analysis of coccidiostats in various matrices, focusing principally on screening and rapid methods. Coccidiosis is an infectious disease having a high negative impact on the animal industry. Drugs are therefore necessary to prevent and/or to combat this disease. However, it is also of crucial importance that these veterinary drugs do not enter the human food chain. European legislation has therefore established the boundaries for the use of coccidiosats and has also addressed the unavoidable problem of cross-contamination of the feed, mainly caused by the use of the same production lines. Consequently there is a need for analytical methods and/or analytical strategies for the monitoring and control of the residues of anticoccidials, both in feed and in the resulting matrices for human consumption. In the frame of the European collaborative project CONffIDENCE, such attempts to establish the required analytical tools were made, which required beforehand a review of the state of the art in this domain. Aiming at this objective, in this review we consider themost interesting publications since 2000. In essence, both a rapid approach with mainly immunoassays and chromatographic methods were developed. To date, the obstacle to routine use of the first approach has been its inability to detect more than two compounds simultaneously, but recent developments in flow cytometry have made it possible to detect six coccidiostats at once. On the other hand, an increasingly popular approach for detecting multiple coccidiostats simultaneously is liquid chromatography coupledwith tandemmass spectrometry. There remains a need to adapt these analytical methods to legislative requirements.
    Critical evaluation of LC-MS-based methods for simultaneous determination of deoxynivalenol, ochratoxin A, zearalenone, aflatoxins, fumonisins and T-2/HT-2 toxins in maize
    Girolamo, A. De; Solfrizzo, M. ; Lattanzio, V.M.T. ; Stroka, J. ; Alldrick, A. ; Egmond, H.P. van; Visconti, A. - \ 2013
    World Mycotoxin Journal 6 (2013)3. - ISSN 1875-0710 - p. 317 - 334.
    tandem mass-spectrometry - performance liquid-chromatography - multi-mycotoxin determination - immunoaffinity cleanup - ht-2 toxins - cereals - ms/ms - food - trichothecenes - t-2
    The results of a proficiency test for the LC-MS/(MS) determination of up to 11 mycotoxins (aflatoxins B1, B2, G1 and G2, fumonisins B1 and B2, ochratoxin A, deoxynivalenol, T-2 and HT-2 toxins and zearalenone) in maize were evaluated to identify possible strengths and weaknesses of various methodologies used by the 41 participating laboratories. The majority of laboratories (56%) used mixtures of acetonitrile:water for extraction. Other laboratories used methanol:water mixtures (17%) or performed two consecutive extractions with phosphate buffer solution (PBS) followed by methanol (15%). Few laboratories used mixtures of acetonitrile:water:methanol (7%), water:ethyl acetate (2.5%) or PBS alone (2.5%). The majority of laboratories (58%) used a clean-up step prior to chromatography. The remaining laboratories analysed crude extracts (37%) or used a mixed approach (5%). The amount of sample equivalent injected into LC-MS/(MS) ranged between 0.1-303 mg for purified extracts and 0.08-20 mg for directly analysed crude extracts. External (54%), matrix-matched (22%) or stable isotope-labelled internal standards calibration (24%) were used for toxin quantification. In general, extraction mixtures of water with acetonitrile, methanol or both provided good results for quantitative extraction of mycotoxins from maize. Laboratories using sample extract clean-up reported acceptable results for the majority of mycotoxins. Good results were also obtained by laboratories that analysed crude extracts although a high variability of results was observed for all tested mycotoxins. Matrix-matched calibration or isotope-labelled internal standards efficiently compensated matrix effects whereas external calibration gave reliable results by injecting =10 mg of matrix equivalent amounts. Unacceptable high recovery and high variability of fumonisin results were obtained by the majority of laboratories, which could not be explained and thus require further investigation. These findings provide the basis for the optimization and selection of methods to be used in future interlaboratory validation studies to derive their performance characteristics for simultaneous determination of mycotoxins in maize.
    Developments in mycotoxin analysis: an update for 2011-2012
    Shephard, G.S. ; Berthiller, F. ; Burdaspal, P. ; Crews, C. ; Jonker, M.A. ; Krska, R. ; MacDonald, S. ; Malone, R.J. ; Maragos, C. ; Sabino, M. ; Solfrizzo, M. ; Egmond, H.P. van; Whitaker, T.B. - \ 2013
    World Mycotoxin Journal 6 (2013)1. - ISSN 1875-0710 - p. 3 - 30.
    performance liquid-chromatography - tandem mass-spectrometry - solid-phase extraction - immunoaffinity column cleanup - surface-plasmon resonance - aflatoxin m-1 contamination - linked-immunosorbent-assay - thin-layer-chromatography - lateral flow immunoassay - di
    This review highlights developments in mycotoxin analysis and sampling over a period between mid-2011 and mid-2012. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. A section on mycotoxins in botanicals and spices is also included. Methods for mycotoxin determination continue to be developed using a wide range of analytical systems ranging from rapid immunochemical-based methods to the latest advances in tandem mass spectrometry. This review follows the format of previous reviews in this series (i.e. sections on individual mycotoxins), but due to the rapid spread and developments in the field of multimycotoxin methods by LC-MS/MS, a separate section has been devoted to advances in this area of research.
    Process analytical technology (PAT) tools for the cultivation step in biopharmaceutical production
    Streefland, M. ; Martens, D.E. ; Beuvery, E.C. ; Wijffels, R.H. - \ 2013
    Engineering in Life Sciences 13 (2013)3. - ISSN 1618-0240 - p. 212 - 223.
    performance liquid-chromatography - time pooling decisions - fed-batch cultures - recombinant protein-production - chemically-defined media - escherichia-coli w3110 - cell culture - therapeutic proteins - approval trends - gene-expression
    The process analytical technology (PAT) initiative is now 10 years old. This has resulted in the development of many tools and software packages dedicated to PAT application on pharmaceutical processes. However, most applications are restricted to small molecule drugs, mainly for the relatively simple process steps like drying or tableting where only a limited number of parameters need to be controlled. A big challenge for PAT still lies in applications for biopharmaceuticals and then especially in the cultivation process step, where the quality of a biopharmaceutical product is largely determined. This review gives an overview of the currently available tools for monitoring and controlling the biopharmaceutical cultivation step and of the main challenges for the most common cell platforms (i.e. Escherichia coli, yeast, and mammalian cells) used in biopharmaceutical manufacturing. The real challenge is to understand how intracellular mechanisms (from synthesis to excretion) influence the quality of biopharmaceuticals and how these mechanisms can be monitored and controlled to yield the desired end product quality. Modern “omics” tools and advanced process analyzers have opened up the way for PAT applications for the biopharmaceutical cultivation process step.
    Quantitative Fate of Chlorogenic Acid during Enzymatic Browning of Potato Juice
    Narvaez Cuenca, C.E. ; Vincken, J.P. ; Gruppen, H. - \ 2013
    Journal of Agricultural and Food Chemistry 61 (2013)7. - ISSN 0021-8561 - p. 1563 - 1572.
    performance liquid-chromatography - trap mass-spectrometry - oxidation-products - apple juice - covalent interactions - caffeoylquinic acid - proteins - tuber - derivatives
    The quantitative fate of chlorogenic acid (ChA) during enzymatic browning of potato juice was investigated. Potato juice was prepared in water without the use of any antibrowning agent (OX treatment). As a control, a potato juice was prepared in the presence of NaHSO3 (S control). To study the composition of phenolic compounds in potato in their native states, also a potato extract was made with 50% (v/v) methanol containing 0.5% (v/v) acetic acid (MeOH control). Water-soluble low molecular weight fractions (LMWFs) and high molecular weight fractions (HMWFs) from S and OX extracts were obtained by ultrafiltration and dialysis, respectively. Pellets obtained after the OX treatment and the S and MeOH controls were also analyzed for ChA content. Whereas in the S-LMWF all ChA was converted to sulfonic acid adducts, no free ChA was found in the OX-LMWF, indicating its high reactivity upon enzymatic browning. Analysis of protein in the HMWFs showed a higher content of “reacted” ChA in OX (49.8 ± 7.1 mg ChA/100 g potato DW) than in S (14.4 ± 1.5 mg ChA/100 g potato DW), as evidenced by quinic acid release upon alkaline hydrolysis. The presence of quinic acid in S-HMWF was unexpected, but a mass balance incorporating the ChA content of LMWF, HMWF, and pellet for the three extractions suggested that ChA might have been attached to polymeric material, soluble in the aqueous environment of S but not in that of MeOH. Size exclusion chromatography, combined with proteolysis, revealed that ChA reacted with patatin and protease inhibitors to produce brown soluble complexes.
    Development and validation of a confirmative LC-MS/MS methode for the determination of ß-exotoxin thuringiensin in plant protection products and selected greenhouse crops
    Rijk, T.C. de; Dam, R.C.J. van; Zomer, P. ; Boers, E.A.M. ; Waard, P. de; Mol, J.G.J. - \ 2013
    Analytical and Bioanalytical Chemistry 405 (2013)5. - ISSN 1618-2642 - p. 1631 - 1639.
    performance liquid-chromatography - heat-stable exotoxin - bacillus-thuringiensis - beta-exotoxin - quantitative-analysis - insecticide - assay
    Bacterial products based on Bacillus thuringiensis are registered in many countries as plant protection products (PPPs) and are widely used as insecticides and nematocides. However, certain B. thuringiensis strains produce harmful toxins and are therefore not allowed to be used as PPPs. The serotype B. thuringiensis thuringiensis produces the beta-exotoxin thuringiensin (ßeT) which is considered to be toxic for almost all forms of life including humans (WHO 1999). The use of a non-registered PPP based on B. thuringiensis thuringiensis called bitoxybacillin was established through the determination of ßeT. First, an analytical reference standard of ßeT was characterized by nuclear magnetic resonance, liquid chromatography–high-resolution mass spectrometry and liquid chromatography–tandem mass spectrometry (LC-MS/MS). Then, a confirmatory quantitative method for the determination of ßeT in PPPs and selected greenhouse crops based on LC-MS/MS was developed and validated. A limit of quantitation of 0.028 mg/kg was established, and average recoveries ranged from 85.6 % to 104.8 % with repeatability (RSDr) of 1.5–7.7 % and within-lab reproducibility (RSDWLR) of 17 %. The method was used for analysis of >100 samples. ßeT was found in leaves of ornamentals, but no evidence was found for use in edible crops.
    A review of analytical strategies for the detection of endogenous' steroid abuse in food production
    Scarth, J.P. ; Kay, J. ; Teale, P. ; Akre, C. ; Bizec, B. le; Brabander, H.F. de; Vanhaecke, L. ; Ginkel, L.A. van; Points, J. - \ 2012
    Drug Testing and Analysis 4 (2012). - ISSN 1942-7603 - p. 40 - 49.
    tandem mass-spectrometry - performance liquid-chromatography - carbon-isotope analysis - meat-producing animals - gas-chromatography - anabolic-steroids - residue analysis - doping control - veal calves - pattern-recognition
    Detection of the abuse of synthetic steroids in food production is nowadays relatively straightforward using modern techniques such as gas or liquid chromatography coupled to mass spectrometry (GC-MS/MS or LC-MS/MS, respectively). However, proving the abuse of endogenous (or naturally occurring) steroids is more difficult. Despite these difficulties, significant progress in this area has recently been made and a number of methods are now available. The aim of the current review was to systematically review the available analytical approaches, which include threshold concentrations, qualitative marker metabolites, intact steroid esters, gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS), longitudinal testing and omics biomarker profiling. The advantages/disadvantages of these methods are considered in detail, but the choice of which to adopt is dictated by a number of practical, political, and economic factors, which vary in different parts of the world. These include the steroid/species combination requiring analysis, the matrix tested, whether samples are collected from live or slaughtered animals, available analytical instrumentation, sample throughput/cost, and the relevant legal/regulatory frameworks. Furthermore, these approaches could be combined in a range of different parallel and/or sequential screening/confirmatory testing streams, with the final choice being determined by the aforementioned considerations. Despite these advances, more work is required to refine the different techniques and to respond to the ever increasing list of compounds classified as endogenous. At this advanced stage, however, it is now more important than ever for scientists and regulators from across the world to communicate and collaborate in order to harmonize and streamline research efforts. (c) 2012 HFL Sport Science (LGC Ltd) and (c) Her Majesty the Queen in Right of Canada.
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