Toxic/mutagenic potentials of Gambierdiscus toxicus (GT) and Prorocentrum lima (PL) methanol extracts (CME) were determined using brine shrimp (Artemia salina), mouse, chicken embryo and Salmonella microsomal assays. PL-CME and GT-CME were toxic to shrimp and mice. Isolation and separation were accomplished using ether/water, hexane/methanol partition and butanol extraction. Toxic fractions were purified using column and thin layer chromatography (TLC). GT-CME showed low levels of mutagenic potential. For GT isolated fractions and PL-CME, no mutagenic effects were observed. Both CMEs showed embryotoxicity, with no teratogenic effects. Ether/methanol and water/butanol fractions showed shrimp toxicity. These fractions were purified by treatment with warm/cold acetone. Acetone insoluble precipitates were obtained. Ether soluble acetone filtrate (ESAF) and butanol soluble acetone precipitate (BSAP) showed shrimp and mouse toxicity. GT-BSAP produced temperature depression in mice. Three toxic isolates were obtained from PL-ESAF, four from GT-ESAF and one from both BSAPs columns. TLC preparative plates showed at least 12 toxic isolates for PL-ESAF, 8 for GT-ESAF and 4 for GT-BSAP.

This study was aimed at investigating the potential of lactic acid fermentation in reducing myco toxin concentration in maize meal products. Maize meal was spiked separately with aflatoxin Bi, fumonism Bi, and zearalenone, and fermented for four days. During this period the concentration of each toxin and the pH of the fermented maize meal were monitored. There was a significant (p= 0.000) decrease in the concentration of all the mycotoxins, with a percentage reduction of 55-69 by the third day and 68-75 by the fourth day, respectively. Commercial amahewu samples were also screened for the presence of these three mycotoxins, and the results indicated that the samples were not contaminated with detectable levels of these toxins. An attempt was made to characterise the metabolic derivatives (by-products) of each mycotoxin following lactic acid maize meal fermentation. To achieve this maize meal samples were separately spiked with each of mycotoxin, fermented for four days and screened for specific mycotoxin derivatives (by-products) using GC/MS, HPLC and relevant standards (i.e. partially hydrolysed fumonisin Bi, aflatoxin B2a, a- and Pzearalenol). None of the targeted derivatives could be detected in the fermented maize meal samples. The potential cytotoxicity of the mycotoxin-spiked fermented samples was investigated using an SNO cell line. The fermented toxin-spiked maize meal samples with a starter culture were comparatively less toxic (29 - 36%) to SNO oesophageal cells than samples spiked with toxin without a starter culture (24 - 30%). However, this observed difference was not statistically significant (p = 0.295 - 0.681). Furthermore, cells that were only inoculated with the cell culture medium had significantly (p = 0.000) high percentage cell viability. This study indicates that it is possible to significantly reduce the concentration of mycotoxins using lactic acid maize fermentation to trace levels. However, such a reduction will not significantly alter the possible chronic toxic effects of such toxins in the diet, particularly a maize based diet containing poor quality protein. The trace amounts of these toxins in fermented and unfermented maize meal should continue to be a cause for concern. / Thesis (M.Med.Sc.)-University of Natal, Durban, 2003.

A segurança alimentar tem sido um tema cada vez mais importante das metas dos órgãos governamentais, não apenas no sentido de garantir que a população dos países tenha acesso a alimentos, mas que estes alimentos estejam dentro de padrões de qualidade nutricional e os limites de resíduos químicos ou microrganismos não causem prejuízos à saúde da população. A comparação entre as legislações existentes no Codex Alimentarius, nos Estados Unidos e no Reino Unido, sobre a maneira como os limites de segurança alimentar de praguicidas são obtidos, permitirá a obtenção de subsídios que, certamente, contribuirão para a construção de uma proposta para a avaliação deste risco no Brasil. A avaliação do risco da ingestão de resíduos de praguicidas presentes no alimento é feita pressupondo-se que Risco = f(toxicidade, exposição), onde a toxicidade é inerente ao praguicida, sendo determinada em estudos conduzidos em animais de laboratório. Já os dados de exposição são oriundos dos estudos de campo e de consumo dos alimentos. Países como os Estados Unidos e o Reino Unido, preconizam que a avaliação do risco deva ser feita por etapas, partindo do cenário mais restritivo e quando este se mostrar impeditivo, fazer um refinamento dos dados, considerando outros cenários de exposição para posterior tomada de decisão. No presente trabalho foram comparados dois praguicidas de uso autorizado no Brasil, nos Estados Unidos e no Reino Unido e que apresentam tolerância estabelecida pelo Codex Alimentarius. Foram utilizados os modelos de cálculo de cada entidade regulamentadora e obtidos os seguintes resultados: no Brasil o Clorpirifós atinge 41,03% da IDA, para as demais entidades o valor é inferior a 4,5% da IDA. No caso do Tebuconazol, observa-se que no Brasil o produto atinge 35, 17 % da IDA e nas demais instituições o valor é inferior a 8% da IDA. Diante dos resultados obtidos, temos que o critério adotado pelo governo brasileiro encontra-se distante da realidade, e embora o valor obtido no cálculo seja maior do que nas demais instituição, este não significa que a população brasileira está mais protegida do que as demais. Existe a necessidade de implementar o banco de dados brasileiro para que a avaliação do risco seja feita de forma mais adequada, possibilitando a geração de informações que suportem o gerenciamento do risco e viabilize medidas adequadas de mitigação deste risco, quando existente. Embora o Brasil seja um membro signatário do Codex Alimentarius muitos critérios e conceitos desta entidade não foram implementados pelo governo brasileiro. / Food safety is an important goal for governmental agencies, not only aiming access to food by populations in all countries, but also assume nutritional quality standards and limits of chemical residues or microorganisms that do not cause damages to the population. The comparison of existing legislations in the Codex Alimentarius, United States and United Kingdom in relation to the procedure on how pesticide limits of food safety are established will allow the attainment of subsidies that, certainly, will contribute for the elaboration of a proposal for risk evaluation in Brazil. Risk evaluation of the ingestion of pesticide residues in food is made estimating that Risk = f(toxicity, exposure), where the toxicity is inherent to the pesticide, and it is determined by animal assays a exposure data are derived from field studies and food consumption. United States and the United Kingdom, consider that risk evaluation must be established by stages, starting from the most restrictive cenario and when it is impeditive, it is necessary a refinement of the data, considering other exposure situations for final decision. ln the present work two pesticides of authorized use in Brazil had been compared, with the United States and the United Kingdom and with the tolerance established for the Codex Alimentarius. The models used for calculation showed that in Brazil, Chlorpyrifos reached 41.03% of the ADI , and the other institutions showed value below of 4,5% of the ADI. In the case of Tebuconazole it is observed that in Brazil the product reaches 35, 17 % of the ADI and in the other institutions the value was lower than 8% of the ADI. The results showed that the criterion adopted by the Brazilian government are unreal, and even if they are higher than the ones found by other institutions, they do not mean that the Brazilian population is more protected than the others. It is necessary to implement Brazilian data base in relation to food consumption so that the risk evaluation can be more reliable and consistent to allow an effective risk management, when needed. Although Brazil is a signatary member of the Codex Alimentarius many criteria and concepts of this entity had not been yet implemented by the government.

A segurança alimentar tem sido um tema cada vez mais importante das metas dos órgãos governamentais, não apenas no sentido de garantir que a população dos países tenha acesso a alimentos, mas que estes alimentos estejam dentro de padrões de qualidade nutricional e os limites de resíduos químicos ou microrganismos não causem prejuízos à saúde da população. A comparação entre as legislações existentes no Codex Alimentarius, nos Estados Unidos e no Reino Unido, sobre a maneira como os limites de segurança alimentar de praguicidas são obtidos, permitirá a obtenção de subsídios que, certamente, contribuirão para a construção de uma proposta para a avaliação deste risco no Brasil. A avaliação do risco da ingestão de resíduos de praguicidas presentes no alimento é feita pressupondo-se que Risco = f(toxicidade, exposição), onde a toxicidade é inerente ao praguicida, sendo determinada em estudos conduzidos em animais de laboratório. Já os dados de exposição são oriundos dos estudos de campo e de consumo dos alimentos. Países como os Estados Unidos e o Reino Unido, preconizam que a avaliação do risco deva ser feita por etapas, partindo do cenário mais restritivo e quando este se mostrar impeditivo, fazer um refinamento dos dados, considerando outros cenários de exposição para posterior tomada de decisão. No presente trabalho foram comparados dois praguicidas de uso autorizado no Brasil, nos Estados Unidos e no Reino Unido e que apresentam tolerância estabelecida pelo Codex Alimentarius. Foram utilizados os modelos de cálculo de cada entidade regulamentadora e obtidos os seguintes resultados: no Brasil o Clorpirifós atinge 41,03% da IDA, para as demais entidades o valor é inferior a 4,5% da IDA. No caso do Tebuconazol, observa-se que no Brasil o produto atinge 35, 17 % da IDA e nas demais instituições o valor é inferior a 8% da IDA. Diante dos resultados obtidos, temos que o critério adotado pelo governo brasileiro encontra-se distante da realidade, e embora o valor obtido no cálculo seja maior do que nas demais instituição, este não significa que a população brasileira está mais protegida do que as demais. Existe a necessidade de implementar o banco de dados brasileiro para que a avaliação do risco seja feita de forma mais adequada, possibilitando a geração de informações que suportem o gerenciamento do risco e viabilize medidas adequadas de mitigação deste risco, quando existente. Embora o Brasil seja um membro signatário do Codex Alimentarius muitos critérios e conceitos desta entidade não foram implementados pelo governo brasileiro. / Food safety is an important goal for governmental agencies, not only aiming access to food by populations in all countries, but also assume nutritional quality standards and limits of chemical residues or microorganisms that do not cause damages to the population. The comparison of existing legislations in the Codex Alimentarius, United States and United Kingdom in relation to the procedure on how pesticide limits of food safety are established will allow the attainment of subsidies that, certainly, will contribute for the elaboration of a proposal for risk evaluation in Brazil. Risk evaluation of the ingestion of pesticide residues in food is made estimating that Risk = f(toxicity, exposure), where the toxicity is inherent to the pesticide, and it is determined by animal assays a exposure data are derived from field studies and food consumption. United States and the United Kingdom, consider that risk evaluation must be established by stages, starting from the most restrictive cenario and when it is impeditive, it is necessary a refinement of the data, considering other exposure situations for final decision. ln the present work two pesticides of authorized use in Brazil had been compared, with the United States and the United Kingdom and with the tolerance established for the Codex Alimentarius. The models used for calculation showed that in Brazil, Chlorpyrifos reached 41.03% of the ADI , and the other institutions showed value below of 4,5% of the ADI. In the case of Tebuconazole it is observed that in Brazil the product reaches 35, 17 % of the ADI and in the other institutions the value was lower than 8% of the ADI. The results showed that the criterion adopted by the Brazilian government are unreal, and even if they are higher than the ones found by other institutions, they do not mean that the Brazilian population is more protected than the others. It is necessary to implement Brazilian data base in relation to food consumption so that the risk evaluation can be more reliable and consistent to allow an effective risk management, when needed. Although Brazil is a signatary member of the Codex Alimentarius many criteria and concepts of this entity had not been yet implemented by the government.

The use of veterinary drugs continues to be a challenge since some farmers use drugs for medicinal purposes, while others use them as growth promoters without observing the set withdrawal times. In emerging economies, challenges are experienced in residue testing to ensure residue free animal products. It is therefore necessary to develop a simple, environmentally friendly and cost effective extraction method for veterinary drugs residues. A dispersive liquid-liquid micro-extraction method for simultaneous determination of chloramphenicol, florfenicol and thiamphenicol residues in water, bovine muscle and milk was developed optimised and validated. Analysis was performed with liquid chromatography coupled to electron spray ionization tandem mass spectrometry in negative ion multiple reaction monitoring mode. Dispersive liquid-liquid micro-extraction method development involved optimisation of parameters such as type and volume of extraction solvent, type and volume of disperser solvent and pH. The optimum extraction solvent was dichloromethane at a volume of 250 μL while the optimum disperser solvent was acetonitrile (1 mL) Extraction was found to be optimum at pH 7. The developed method was validated according to Commission decision 2002/657/EC. Linearity. Linearity was observed for water, bovine milk and muscle in the ranges of 0.3 μg kg-1 to 0.9 μg kg-1, 25 μg kg-1 to 100 μg kg-1 and 50 μg kg-1 to 200 μg kg-1 for chloramphenicol, thiamphenicol and florfenicol respectively with regression coefficients ranging between 0.9941 and 0.9999. Limit of detections for CAP, FFC & THAP were 0.082, 3.31, and 2.21 μg kg-1 respectively while Limit of quantifications were 0.163, 7.51 and 6.84 μg kg-1 respectively. The recoveries for water, bovine milk and bovine muscle ranged between 87.2% and 102%. In this study the validated dispersive liquid-liquid micro-extraction has been found to perform very well not only in the water matrix but also in the more complex matrices like bovine milk and muscle. / Chemistry / M. Sc. (Chemistry)

Food contact materials are materials that are intended to come into contact with food, and we are exposed to different types of chemicals that exist in the packages on a daily basis. In this study, a battery of effect‑based in vitro cellular bioassays was used to evaluate the presence of bioactive compounds in commonly used food contact materials made of paper and cardboard, retrieved from the Swedish market. Sample extracts were tested at concentrations 0.3, 1, 3 and 10 mg food contact material/mL cell culture medium. The use of effect-based bioassays allowed for screening of multiple health-relevant endpoints in a non-targeted approach. Hence, taking unknown substances and mixtures into consideration when addressing potential toxicity of the materials. In essence, detection of bioactivity could be considered as moderate to high in assays of positive effects. Antiandrogenic and antiestrogenic effects were found in 72% of the samples, followed by 47% bioactivity in the Nrf2 assay. No androgenic effect was detected. Usage of effect-based bioassays allows for high sensitivity and low detection limits, and these can be used as a first approach to evaluate package materials to ensure the safety of consumers. / Livsmedelsförpackningar är material som är avsedda att komma i kontakt med livsmedel. Vi exponeras för olika typer av kemikalier som existerar i dessa förpackningar varje dag. I denna studie användes ett batteri av effektbaserade in vitro bioanalytiska metoder för att undersöka förekomst av bioaktiva ämnen i vanligen använda livsmedelsförpackningar tillverkade av papper och kartong, insamlade från den svenska marknaden. Provextrakten testades i koncentrationerna 0.3, 1, 3 och 10 mg livsmedelsförpackning/mL cellmedium. Att använda effektbaserade bioanalyser möjliggör undersökning av flertalet hälsorelevanta effekter genom en icke-riktad strategi. På så sätt tas okända substanser och komplexa blandningar i beaktande. Andelen bioaktiva prover kan anses måttlig till hög för positiva analyser. Antiandrogena och antiöstrogena effekter detekterades i 72% av proverna, följt av 47% bioaktivitet i Nrf2 analysen. Ingen agonistisk androgen effekt observerades. Att använda effektbaserade bioanalyser möjliggör hög sensitivitet och detektion vid låga koncentrationer, därför kan dessa användas som ett första steg för att evaluera förpackningsmaterial för att säkra konsumenternas hälsa.

O objetivo principal deste estudo foi o desenvolvimento e validação de metodologia de análise de multiresíduos para quantificação de resíduos de pesticidas em manga. Foram analisados 32 pesticidas, sendo dos seguintes grupos: 9 Organofosforados, 17 Organoclorados e 6 triazois sendo que neste mesmo método foi analisado novamente o Organofosforado fention. Os organofosforados foram analisados em cromatógrafo a gás (CG) acoplado ao detector fotométrico de chamas e os organoclorados foram analisados em cromatógrafo a gás (CG) acoplado ao detector de captura de elétrons (ECD). Os triazois foram analisados em cromatógrafo a gás acoplado a espectrômetro de massa (CG/MS). A curva de linearidade para todos os padrões analíticos, foi realizada em triplicata e com 6 diferentes concentrações. As fortificações das amostras foram realizadas em dois níveis de concentração, no limite do método e 10 vezes o limite do método, sendo que a concentração do limite de quantificação do método (LOQ) foi realizada com sete repetições (N= 7) e a concentração de 10 vezes o LOQ foi realizada com N= 5, usando-se mangas tratadas no sistema orgânico (livres de pesticidas). Os métodos desenvolvidos e validados neste estudo apresentaram-se: a) Linear na faixa de: 0,1 - 4,0 µg/mL para o triclorfon e malation; 0,05 – 2,0 µg/mL para os demais organofosforados; 0,05 – 1,6 µg/mL para os organoclorados; 0,1 – 1,0 µg/mL para o paclobutrazol; 0,25 - 2,5 µg/mL para o fention e bromuconazol; 0,5 – 5,0 µg/mL para o tetraconazol e tebuconazol e 1,0 – 10 µg/mL para o procloraz e difenoconazol respectivamente, uma vez que o coeficiente de determinação foi maior que 0,99 para todos os ativos. b) Específicos, pois o nível de contaminação e/ou interferente na análise do branco dos reagentes e da amostra testemunha, foram inferiores a 30% do limite de quantificação. c) Exato, Preciso e Repetitivo, pois todos os ativos apresentaram recuperação dentro do intervalo de aceitabilidade de 70 a 120%, com coeficiente de variação porcentual (CV%) inferior a 15% em relação à média global de todos os níveis de fortificação. Foram também analisados os mesmos pesticidas em 15 amostras de mangas compradas nos supermercados de Piracicaba, procedentes do Nordeste do Brasil. Em nenhuma das amostras foram encontrados resíduos acima do limite estabelecido por lei ou acima do limite de quantificação deste método, no caso dos pesticidas não autorizados. / The principal objective of this study was the development and validation of a multiresidue analytical methodology for the quantification of pesticide residues in mangos. Quantitative analyses were made for 32 pesticides, from the following classes: organophosphorus (9), organochlorine (17) and triazole (6). The results from the method include the first analysis for the organophosphorus pesticide fenthion. The organophosphorus pesticides were analyzed by a gas chromatograph (GC) coupled to a flame photometric detector, while the organochlorine pesticides were analyzed using a gas chromatograph (GC) coupled to an electron capture detector (ECD). The triazoles were analyzed with a gas chromatograph coupled to a mass spectrometer (GC/MS). For each of the analytes, calibration curves were constructed in triplicate using solutions with six different concentrations, prepared from the analytical standards. Recovery experiments were performed at two levels of fortification, the limit of quantification of the method (LOQ) and 10 times this limit. Seven repetitions (N = 7) were performed at the limit of quantification, and five (N = 5) at the 10 times higher level of fortification. Mangos raised by organic farming methods (free from pesticides) were used for the recovery experiments. The methods developed and validated in this study have the following characteristics: a) linear range: 0.1 – 4.0 µg/mL for trichlorfon and malathion; 0.05 – 2.0 µg/mL for the other organophosphorus pesticides; 0.05 – 1.6 µg/mL for the organochloro pesticides; 0.1 – 1.0 µg/mL for paclobutrazol; 0.25 – 2.5 µg/mL for fenthion and bromuconazole; 0.5 – 5.0 µg/mL for tetraconazole and tebuconazole; and 1.0 – 10.0 µg/mL for prochloraz and difenoconazole, in each case the coefficient of determination was greater than 0.99. b) Specific: thus the level of contamination and/or intereference in analysis from the reagent blank and the control sample amounted to less than 30% of the limit of quantification. c) Exact, Precise and Repeatable, for each of the analytes the recovery was found to be within the acceptable interval of 70 to 120%, and with a coefficient of variation, expressed as a percentage, of less than 15% in relation to the global average of the results obtained at the two levels of fortification. Analyses were made for the same pesticides in 15 samples of mangos bought from supermarkets in Piracicaba, which were raised in the Northeast of Brazil. None of these samples contained residue concentrations above the limit established by law or, in the case of non-authorized pesticides, above the limit of the quantification of the current methodology.

O presente trabalho visa desenvolver métodos que permitam determinar as concentrações de tetraciclina, por Cromatografia Líquida de Alta Eficiência, no plasma e líquido sinovial, além de analisar as concentrações correspondentes em leite de gado leiteiro em lactação submetidos aos tratamentos intravenoso e intravenoso regional. Desta forma, objetivando determinar a depuração da tetracic1ina no organismo dos animais tratados, a concentração do fármaco no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequados à quantificação do antibiótico nas matrizes biológicas estudadas. As amostras de leite de animais tratados com o medicamento por via intravenosa regional, não apresentaram resíduos após 120h da administração do fármaco. O mesmo ocorreu plasma e líquido sinovial após 48 h. Através da administração via intravenosa do medicamento foram observados resíduos no leite em todos os tempos avaliados, ao passo que no plasma e líquido sinovial, a presença do princípio ativo não foi detectada após 72 horas pós-tratamento. / The purpose of the present work is to develop methods which allow the determination of tetracycline by High Pressure Liquid Chromatography in serum, synovial fluid, as well as analyze the corresponding milk concentrations in milk cows subjected to intravenous and regional intravenous treatment. Therefore, aiming to determine the clearance of tetracycline in the body of the treated animals, the concentration of the active principle in the action site and the residual quantity in milk, biological matrices were collected at different times. The validated analytical methods depicted suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing the quantification of the antibiotic in the studied biological matrices. In relation to the milk samples from animals treated with the drug by regional intravenous via, they did not present residues of tetracycline after 120 h post-administration. The values were also null for both serum and synovial fluid after 48 h. Through regional intravenous drug administration, milk residues were observed in all the evaluated times whereas for serum and synovial fluid, the presence of the active principle was not detected after 72h post-treatment.

O objetivo principal deste estudo foi o desenvolvimento e validação de metodologia de análise de multiresíduos para quantificação de resíduos de pesticidas em manga. Foram analisados 32 pesticidas, sendo dos seguintes grupos: 9 Organofosforados, 17 Organoclorados e 6 triazois sendo que neste mesmo método foi analisado novamente o Organofosforado fention. Os organofosforados foram analisados em cromatógrafo a gás (CG) acoplado ao detector fotométrico de chamas e os organoclorados foram analisados em cromatógrafo a gás (CG) acoplado ao detector de captura de elétrons (ECD). Os triazois foram analisados em cromatógrafo a gás acoplado a espectrômetro de massa (CG/MS). A curva de linearidade para todos os padrões analíticos, foi realizada em triplicata e com 6 diferentes concentrações. As fortificações das amostras foram realizadas em dois níveis de concentração, no limite do método e 10 vezes o limite do método, sendo que a concentração do limite de quantificação do método (LOQ) foi realizada com sete repetições (N= 7) e a concentração de 10 vezes o LOQ foi realizada com N= 5, usando-se mangas tratadas no sistema orgânico (livres de pesticidas). Os métodos desenvolvidos e validados neste estudo apresentaram-se: a) Linear na faixa de: 0,1 - 4,0 µg/mL para o triclorfon e malation; 0,05 – 2,0 µg/mL para os demais organofosforados; 0,05 – 1,6 µg/mL para os organoclorados; 0,1 – 1,0 µg/mL para o paclobutrazol; 0,25 - 2,5 µg/mL para o fention e bromuconazol; 0,5 – 5,0 µg/mL para o tetraconazol e tebuconazol e 1,0 – 10 µg/mL para o procloraz e difenoconazol respectivamente, uma vez que o coeficiente de determinação foi maior que 0,99 para todos os ativos. b) Específicos, pois o nível de contaminação e/ou interferente na análise do branco dos reagentes e da amostra testemunha, foram inferiores a 30% do limite de quantificação. c) Exato, Preciso e Repetitivo, pois todos os ativos apresentaram recuperação dentro do intervalo de aceitabilidade de 70 a 120%, com coeficiente de variação porcentual (CV%) inferior a 15% em relação à média global de todos os níveis de fortificação. Foram também analisados os mesmos pesticidas em 15 amostras de mangas compradas nos supermercados de Piracicaba, procedentes do Nordeste do Brasil. Em nenhuma das amostras foram encontrados resíduos acima do limite estabelecido por lei ou acima do limite de quantificação deste método, no caso dos pesticidas não autorizados. / The principal objective of this study was the development and validation of a multiresidue analytical methodology for the quantification of pesticide residues in mangos. Quantitative analyses were made for 32 pesticides, from the following classes: organophosphorus (9), organochlorine (17) and triazole (6). The results from the method include the first analysis for the organophosphorus pesticide fenthion. The organophosphorus pesticides were analyzed by a gas chromatograph (GC) coupled to a flame photometric detector, while the organochlorine pesticides were analyzed using a gas chromatograph (GC) coupled to an electron capture detector (ECD). The triazoles were analyzed with a gas chromatograph coupled to a mass spectrometer (GC/MS). For each of the analytes, calibration curves were constructed in triplicate using solutions with six different concentrations, prepared from the analytical standards. Recovery experiments were performed at two levels of fortification, the limit of quantification of the method (LOQ) and 10 times this limit. Seven repetitions (N = 7) were performed at the limit of quantification, and five (N = 5) at the 10 times higher level of fortification. Mangos raised by organic farming methods (free from pesticides) were used for the recovery experiments. The methods developed and validated in this study have the following characteristics: a) linear range: 0.1 – 4.0 µg/mL for trichlorfon and malathion; 0.05 – 2.0 µg/mL for the other organophosphorus pesticides; 0.05 – 1.6 µg/mL for the organochloro pesticides; 0.1 – 1.0 µg/mL for paclobutrazol; 0.25 – 2.5 µg/mL for fenthion and bromuconazole; 0.5 – 5.0 µg/mL for tetraconazole and tebuconazole; and 1.0 – 10.0 µg/mL for prochloraz and difenoconazole, in each case the coefficient of determination was greater than 0.99. b) Specific: thus the level of contamination and/or intereference in analysis from the reagent blank and the control sample amounted to less than 30% of the limit of quantification. c) Exact, Precise and Repeatable, for each of the analytes the recovery was found to be within the acceptable interval of 70 to 120%, and with a coefficient of variation, expressed as a percentage, of less than 15% in relation to the global average of the results obtained at the two levels of fortification. Analyses were made for the same pesticides in 15 samples of mangos bought from supermarkets in Piracicaba, which were raised in the Northeast of Brazil. None of these samples contained residue concentrations above the limit established by law or, in the case of non-authorized pesticides, above the limit of the quantification of the current methodology.

O presente trabalho visa desenvolver métodos que permitam determinar as concentrações de tetraciclina, por Cromatografia Líquida de Alta Eficiência, no plasma e líquido sinovial, além de analisar as concentrações correspondentes em leite de gado leiteiro em lactação submetidos aos tratamentos intravenoso e intravenoso regional. Desta forma, objetivando determinar a depuração da tetracic1ina no organismo dos animais tratados, a concentração do fármaco no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequados à quantificação do antibiótico nas matrizes biológicas estudadas. As amostras de leite de animais tratados com o medicamento por via intravenosa regional, não apresentaram resíduos após 120h da administração do fármaco. O mesmo ocorreu plasma e líquido sinovial após 48 h. Através da administração via intravenosa do medicamento foram observados resíduos no leite em todos os tempos avaliados, ao passo que no plasma e líquido sinovial, a presença do princípio ativo não foi detectada após 72 horas pós-tratamento. / The purpose of the present work is to develop methods which allow the determination of tetracycline by High Pressure Liquid Chromatography in serum, synovial fluid, as well as analyze the corresponding milk concentrations in milk cows subjected to intravenous and regional intravenous treatment. Therefore, aiming to determine the clearance of tetracycline in the body of the treated animals, the concentration of the active principle in the action site and the residual quantity in milk, biological matrices were collected at different times. The validated analytical methods depicted suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing the quantification of the antibiotic in the studied biological matrices. In relation to the milk samples from animals treated with the drug by regional intravenous via, they did not present residues of tetracycline after 120 h post-administration. The values were also null for both serum and synovial fluid after 48 h. Through regional intravenous drug administration, milk residues were observed in all the evaluated times whereas for serum and synovial fluid, the presence of the active principle was not detected after 72h post-treatment.