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Tetracycline antibiotics, including tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC) and doxycycline (DOX), are commonly used in veterinary medicine because of their broad-spectrum activity, cost effectiveness and certain favourable pharmacokinetic properties. The use of antibiotics in feed for non-medicinal purposes has been prohibited in the European Union. In Poland and other countries of the European Union, there are official national programmes for controlling the use of TCs and all other antibacterials in feed. This paper presents the pharmacological properties of TCs as well as the main reasons for and consequences of their use in feed. It also presents a chromatographic method for detection of TCs in animal feeds. The method is used in routine testing of food for the presence of tetracycline antibiotics. In the years 2015-2017, tetracycline antibiotics were detected in 31 out of 126 feed samples analysed by this method.
Analytical procedure for determination of glyceroltriheptanoate (GTH) in processed animal by-products was developed. Samples of meat and bone meal were sieved through 1 mm sieve, extracted with petroleum ether, and cleaned up on amino bonded solid phase extraction cartridges. Extracts were analysed with a gas chromatograph combined with flame ionisation detector, on DB5 capillary column (30 m, 0.25 mm, 0.25 µm). The whole procedure was validated. Validation parameters, i.e., recovery in the range 80%-91%, depending on the substance concentration, repeatability 2.17%-8.79%, and linearity R² >0.999, confirmed the suitability of the method for determination of GTH in processed animal by-products.
Animal by-products result mainly from the slaughter of animals for human consumption, the production of products of animal origin (such as dairy products), the disposal of dead animals, and disease-control measures. Regardless of their source, they pose a potential risk to public and animal health and the environment. This risk needs to be adequately controlled, either by safe disposal of such products, or by their utilization, provided that strict conditions are maintained to minimize the health risks involved. Animal by-products are classified into categories that reflect the level of risk to public and animal health arising from those by-products (Cat. 1, 2 and 3). According to Commission Regulation (EU) No 142/2011, in processing plants for the processing of Category 1 or 2 material, derived products shall be permanently marked with glycerol triheptanoate (GTH). The minimum content of marker in target materials is 250 mg/kg of fat. For the determination of glycerol triheptanoate in dry meat, bone meals, rendered fat and soil adjuvants, gas chromatography technique and mass spectrometry detection are used.
A high performance liquid chromatography combined with fluorescence detection (HPLC-FLD) method was developed for determination of five ergot alkaloids (EA): ergometrine, ergotamine, ergocornine, ergocrypine and ergocristine in animal feedingstuffs. The method was based on the application of QuEChERS salts for extraction and modified QuEChERS dispersive SPE for the cleanup step. Alkaloids separation was performed on a C18, 250 mm x 4.6 mm, 5 μm column with the mobile phase containing ammonium carbonate and acetonitrile. The excitation and emission wavelengths were 330 and 420 nm respectively. The method was validated according to the Commission Decision 2002/657/EC and all parameters are in agreement with the requirements of the Decision. Linearity was determined for the concentration range of 25-400 μg/kg. The coefficient of determination (R2) for all curves was from 0.985 to 0.996. The limit of detection (LOD) was in the range 3.23 to 6.53 μg/kg and the limit of quantification (LOQ) from 11.78 to 13.06 μg/kg. The decision limit (CCα) ranged from 29.56 to 43.08 μg/kg and detection capability (CCβ) from 40.65 to 51.01 μg/kg. The highest coefficient of variation (CV) for repeatability was 14.3% and for reproducibility 15.4%.
A liquid chromatography - diode array detector (HPLC-DAD) procedure has been developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlorotetracycline (CTC), doxycyc-line (DC), enrofloxacin (ENR), ciprofloxacin (CIP), sarafloxacin (SAR) and flumequine (FLU) residues in animal drinking water. This method was applied to animal drinking water. Solid-phase extraction (SPE) clean-up on an Oasis HLB cartridge allowed an extract suitable for liquid chromatographic analysis to be obtained. Chromatographic separation was carried out on a C18 analytical column, using gradient elution with 0.1% trifluoroacetic acid - acetonitrile - methanol at 30oC. The flow-rate was 0.7 mL/min and the eluate was analysed at 330 nm. The whole procedure was evaluated according to the requirements of the Commission Decision 2002/657/EC, determining specificity, decision limit (CCa), detection capacity (CCß), limit of detection (LOD), limit of quantification (LOQ), precision and accuracy during validation of the method. The recoveries of TCs and FQs from spiked samples at the levels of 10, 100 and 1000 ^g/L were higher than 82%. The developed method based on HPLC-DAD has been applied for the determination of four tetracyclines and four fluoroquinolones in animal drinking water samples.
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