The occurrence of antimicrobials in the aquatic environment and drinking water has raised the question of their impact on the environment and public health. Animal production is one of the most expressive activities of Brazilian agribusiness. In order to ensure the productivity and competitiveness of the sector, the use of drugs for therapeutic and prophylactic purposes is a common practice. Due to the continuous release of antimicrobials into the environment, the aim of this study was to compare the frequency of detection of tetracyclines and sulfonamides in surface water collected from rural areas in Lidice District of Rio Claro, in the State of Rio de Janeiro, Brazil. An investigative study was conducted with 24 river water samples analyzed by high-performance liquid chromatography coupled to tandem mass spectrometry and the aim of this study was to determine residues of sulfonamides and tetracyclines based on the USEPA me- M. A. Monteiro et al.231

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A simple extraction technique has been developed for seven macrolide antibiotics in milk. The procedure involves a modified quick, easy, cheap, effective, rugged, and safe method based on acetonitrile extraction, followed by the addition of a mixture of salts (sodium sulfate, sodium chloride, and potassium carbonate) not yet reported in literature. The method was validated for tylosin and was selective, free of matrix effect, and linear in the range of 0.78-18.75 ng/mL in the final extract, corresponding to 0.125-3 times the maximum residue limit. The limit of detection, limit of quantification, decision limit, and detection capability were, respectively, 0.84, 2.79, 58.4, and 71.7 μg/kg. The overall average recovery at 25, 50, and 75 μg/kg ranged from 89-97%. Repeatability and intermediate precision expressed by relative standard deviations were below 10.5 and 12%, respectively. The extension of the validation for spiramycin, throleandomycin, oleandomycin, roxithromycin, erythromycin, and clarithromycin is under consideration since the procedure proved to be able to efficiently extract all studied macrolides, with recoveries from 74-104% at 50 μg/kg for tylosin, erythromycin, spiramycin, and oleandomycin and 20 μg/kg for throleandomycin, roxithromycin, and clarithromycin.

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Two analytical methods for determination of five antibiotics classes in surface water and drinking water samples were developed and validated based on solid phase extraction followed by high-performance liquid chromatography coupled to tandem mass spectrometry. Two distinct chromatographic gradients were used according to the polarity of the different pharmaceuticals. The methods were applied for the quantification of 46 analytes belonging to beta-lactams, macrolides, fluoroquinolones, sulfonamides and tetracyclines classes. Validation results showed recoveries above 75% for the studied analytes in water samples. The method limits of detection calculated for the surface water and drinking water samples were, respectively, from 1 to 12 ng L -1 and from 0.15 to 20 ng L -1 . The method limit of quantification ranged from approximately 3 to 38 ng L -1 for surface water samples and from 0.5 to 64 ng L -1 for drinking water samples. The methods showed to be linear over the range of 25 to 1000 ng L -1 with coefficients of determination greater than 0.94. Amoxicillin, cephalexin and sulfamethoxazole as high as 105 ng L -1 were found in surface water and erythromycin, azithromycin and clarithromycin up to 35 ng L -1 could also be found in surface water. Clarithromycin, cefaclor, oxacillin, sulfamethoxazole and troleandomycin were detected in the lower range up to 10 ng L -1 in drinking water.

This pilot survey aimed to assess the occurrence of tetracyclines and the 4-epimers of oxytetracycline, tetracycline and chlortetracycline in commercial pasteurized milks sold in the metropolitan area of Rio de Janeiro, Brazil, between October 2009 and March 2010. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, developed and validated in our laboratory, was used. All 100 analyzed samples were compliant, but 14 contained oxytetracycline in concentrations ranging from the method limit of detection (3.7 µg l(-1)) to the method limit of quantification (12.2 µg l(-1)). One sample contained oxytetracycline and tetracycline simultaneously (at a concentration slightly higher than method limit of quantification, 7.0 µg l(-1)). The presence of 4-epioxytetracycline and 4-epitetracycline in contaminated samples with the parent drugs could not be confirmed as traces were detected only in the quantification MRM transition. No other tetracyclines were detected.

O objetivo deste trabalho foi elaborar um panorama sobre a ocorrência de resíduos de medicamentos veterinários em leite no Brasil, compilando tanto os publicados por autoridades governamentais quanto por instituições acadêmicas. Os dados foram obtidos por meio de pesquisa bibliográfica. Esta pesquisa identificou 35 publicações sobre monitoramentos de resíduos de medicamentos veterinários em leite no país, das quais 34 apresentaram dados sobre o monitoramento de resíduos de antimicrobianos e 10 sobre a ocorrência de resíduos de antiparasitários. Quanto ao número de ocorrências de resíduos de antimicrobianos no leite, os beta-lactâmicos e as tetraciclinas foram os responsáveis pela maior incidência de amostras com resultados acima dos limites de detecção dos métodos empregados. 4 das 9 referências encontradas sobre monitoramentos de anfenicóis apresentaram a ocorrência de cloranfenicol e florfenicol. Apenas três referências apresentaram a ocorrência de amostras com teores acima do Limite Máximo de Resíduos (LMR), cujos analitos foram a benzilpenicilina, da classe dos beta-lactâmicos e o aminoglicosídeo estreptomicina/diidroestreptomicina. Apenas 7 (20,0%) das referências avaliadas apresentaram resultados insatisfatórios para antimicrobianos com relação à legislação brasileira. Com relação aos antiparasitários, 5 de 10 referências (50,0%) apresentaram resultados acima do LMR.