RESUMO
Tambaqui (Colossoma macropomum Cuvier, 1818) is the main native fish species farmed in Brazil, and 17ß-estradiol (E2) is a natural steroid hormone commonly used for the production of female fish monosex population, which, in tambaqui, shows a higher growth rate than the male. Thus, to assess whether the fish meat of treated tambaqui contains hormonal residue levels, a high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS) method for the determination of E2 residues in fish muscle was developed and validated. A QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) dispersive solid phase extraction method was used for the sample preparation. The chromatographic separation was performed in a Poroshel EC-18 reverse phase column. The mobile phase was a mixture of acetonitrile with 0.01% ammonium hydroxide (A) and water with 0.01% ammonium hydroxide (B). The ratio of A:B phases was 60:40 (v/v) used in an isocratic mode. The method validation was performed according to Commission Decision 2002/657/EC and Veterinary International Conference Harmonization (VICH GL49). Since matrix effects were observed, matrix-matched analytical curves are recommended for quantitation. The linearity, selectivity, intraday and interday precision, accuracy, decision limit, detection capability, and detection and quantitation limits of the method are reported. The limits of detection and quantitation were 0.3â¯ng/g and 1.0â¯ng/g, respectively. At these limits and slaughtering fish 7â¯months after the end of the treatment, the muscle of tambaqui did not show detectable hormone residue level. Thus, consumption of tambaqui edible tissue from fish treated with E2 for the purpose of sexual reversion is unlikely to represent a risk associated with the exposure of human subjects as residue levels of this hormone are not detected in the fish muscle.
Assuntos
Caraciformes/metabolismo , Caraciformes/fisiologia , Cromatografia Líquida/métodos , Resíduos de Drogas/análise , Estradiol/análise , Músculos/química , Espectrometria de Massas em Tandem/métodos , Animais , Aquicultura , Feminino , Limite de Detecção , Modelos Lineares , Masculino , Reprodutibilidade dos Testes , Processos de Determinação SexualRESUMO
Ractopamine (RAC), is a ß-adrenergic agonist increasingly used in the swine and cattle industry. This compound redirects nutrients to favour leanness rather than fat deposition, improves growth and carcass traits gaining higher economic benefit to producers. Countries around the world are split over whether to allow the use of RAC in meat production. Clenbuterol (CLB) and salbutamol (SLB) are anillinic and phenolic ß-agonists, respectively, with the same capacity of producing economic benefits for the meat sector. However, they are prohibited because of the potentially adverse reactions they can cause in consumers. The three ß-agonist compounds have been included in the Brazilian National Regulatory Survey and consequentially there is an eminent need for reliable methods capable of detecting those substances at the same time and reduce analytical costs. Therefore, an LC-MS/MS method for the simultaneous determination of residual RAC, CLB and SAL in swine and cattle muscle was developed and validated with quantification levels respecting the action levels established for Brazil which are 0.1, 0.2 and 5 µg kg-1 for RAC, CLB and SAL, respectively. Samples were quantified using RAC-d5, CLB-d9 and SLB-d6 as internal standards. The validation was performed according to European Union Decision 2002/657, which includes criteria (CCα, CCß, recovery, repeatability, reproducibility and calibration curve). The method meets the Brazilian regulatory requirement that establishes criteria and procedures for the determination of parameters such as CCα, CCß, precision and recovery. CCα values were 0.02, 0.21 and 5.42 µg kg-1 for RAC, CLB and SAL, respectively, in bovine and swine muscle samples; CCß values were 0.03, 0.22 and 5.8 µg kg-1 for RAC, CLB and SAL, respectively, in bovine and swine muscle samples. Average recoveries fortified with 0.05-7.5 µg kg-1 of the studied ß-agonist leads around 95%. The method was demonstrated to be suitable for the determination of RAC, CLB and SLB in swine and cattle muscle samples.
Assuntos
Albuterol/análise , Clembuterol/análise , Músculos/química , Fenetilaminas/análise , Animais , Brasil , Bovinos , Cromatografia Líquida de Alta Pressão , Laboratórios , Limite de Detecção , Suínos , Espectrometria de Massas em TandemRESUMO
Nitroimidazoles are a class of veterinary drugs used for the treatment and prevention of certain bacterial and protozoal diseases in poultry, swine dysentery and genital trichomoniasis in cattle. Since the safety assessment of nitroimidazoles showed them to be genotoxic, carcinogenic and mutagenic, a number of nitroimidazoles have been banned for therapeutic purposes in different countries. Moreover, nitroimidazoles have also been extensively used as growth promoters in food-producing animals. Due to their efficacious improvement in meat production and feed conversion, deliberate use still exists. Therefore, the illegal use of nitroimidazoles in animal husbandry must be monitored. A sensitive method based on LC-MS/MS for the simultaneous determination and confirmation of five banned nitroimidazole drugs including metronidazole, ronidazole, dimetridazole, metronidazole-OH (metabolite of metronidazole), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (metabolite of ronidazole and dimetridazole) in bovine muscle, using ronidazole-d3 as an internal standard, was developed and validated. After extraction with ethyl acetate and evaporation, the nitroimidazoles were reconstituted in petroleum ether and purified, and LC-MS/MS analysis was performed. The method was validated according to Brazilian Regulation 24/2009 (equivalent to European Union Decision 2002/657/EC). Parameters such as decision limit (CCα), detection capability (CCß), precision, accuracy, uncertaincy and ruggedness were determined. Average accuracy of the five nitroimidazoles from bovine muscle fortified at 5 levels (0.5, 1.0, 1.5, 2.0 and 2.5 µg kg(-1)) ranged from 96% to 103%. The calculated CCα ranged from 0.0 to 0.17 µg kg(-1); CCß ranged from 0.08 to 0.41 µg kg(-1). A complete statistical analysis was performed and the results indicate that the method is robust when subjected to day-to-day analytical variations.
Assuntos
Anti-Infecciosos/análise , Cromatografia Líquida/métodos , Resíduos de Drogas/análise , Músculos/química , Espectrometria de Massas em Tandem/métodos , Animais , Bovinos , Limite de Detecção , Padrões de Referência , Reprodutibilidade dos TestesRESUMO
Khaya ivorensis with and without symptoms of stem and branch cankers, caused by Botryosphaeria rhodina were examined in order to determine whether the secondary metabolites in this plant were associated with a chemical defense response. This study provides evidence that the limonoid methyl angolensate (MA) is present at higher concentrations in K. ivorensis with symptoms of stem cankers rather than in the plants without symptoms. A rapid, sensitive and selective HPLC-ESI-MS/MS method (using selected reaction monitoring--SRM--mode) was developed for quantification of MA in all aerials parts of such plants, with a good linearity over a range of 0.1-20.0 g/kg, with r(2)>0.996+/-6.1%. The limits of detection (LOD) and quantification (LOQ) were less than 0.03 g/kg and 0.08 g/kg, respectively. Relative Standard Deviations (RSDs) ranged from 1.7% to 19.2% for all matrices. While the MA concentration did not change in the stem bark, its amounts increased nearly fourfold in stems and by 20% in leaves, when plants with symptoms were compared with those without symptoms. These data suggest that MA plays a role in plant-pathogen interactions, probably as a phytoanticipin.