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A method for the determination of dioxins, planar PCBs and other PCBs in human milk is described. The work is part of a big Dutch project, (seven institutes participates) in which 400 human milk samples from two areas (Rotterdam and Groningen) taken at two different times (10 and 42 days) after delivery had to be analysed for planar PCBs, dioxins and other(More)
The use of nitrofurans as veterinary drugs has been banned in the EU since 1993 due to doubts on the safety of the protein-bound residues of these drugs in edible products. Following treatment of pigs with the veterinary drug furazolidone free 3-amino-2-oxazolidinone (AOZ), the side-chain of the drug, could be detected in the blood in concentrations up to(More)
New anabolic steroids show up occasionally in sports doping and in veterinary control. The discovery of these designer steroids is facilitated by findings of illicit preparations, thus allowing bioactivity testing, structure elucidation using NMR and mass spectrometry, and final incorporation in urine testing. However, as long as these preparations remain(More)
A liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) method was developed using the latest high-resolution LC column technology, the ultra performance liquid chromatography (UPLC), and electrospray ionization (ESI) in the positive ion mode. Gradient UPLC separation conditions were optimized for a group of 22 analytes comprising 17(More)
GC-MS data on veterinary drug residues in bovine urine are used for controlling the illegal practice of fattening cattle. According to current detection criteria, peak patterns of preferably four ions should agree within 10 or 20% from a corresponding standard pattern. These criteria are rigid, rather arbitrary and do not match daily practice. A new model,(More)
A method is described for the identification and quantitative determination of 3,5-dinitrosalicylic acid hydrazide (DSH), the marker residue of nifursol metabolites in poultry (turkey, broiler) muscle and liver tissue. The method is based on the acid-catalysed hydrolysis of tissue-bound metabolites to free DSH and in situ derivatisation with(More)
Ultra-performance liquid chromatography combined with time-of-flight mass spectrometry (UPLC-ToF-MS) has been used for screening and quantification of more than 100 veterinary drugs in milk. The veterinary drugs represent different classes including benzimidazoles, macrolides, penicillins, quinolones, sulphonamides, pyrimidines, tetracylines,(More)
Depletion of the nitrofuran antibiotics furazolidone, furaltadone, nitrofurantoin and nitrofurazone and their tissue-bound metabolites AOZ, AMOZ, AHD and SEM from pig muscle, liver and kidney tissues is described. Groups of pigs were given feed medicated with one of the nitrofuran drugs at a therapeutic concentration (400?mg?kg(-1)) for ten days. Animals(More)
A new approach to the search for residues of known and unknown estrogens in calf urine is presented. Following enzymatic deconjugation and solid-phase extraction, a minor part of the samples is screened for estrogen activity using a recently developed rapid reporter gene bioassay. The remainder of the bioactive extracts is analyzed by gradient liquid(More)
The abuse of esters of natural androgenic steroids in cattle fattening and sports is hard to control via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. In veterinary control strange findings of 17beta-testosterone and 17alpha-testosterone in urine are often ignored because of(More)