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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Desenvolvimento e validação de metodologia para determinação de resíduos de pesticidas piretróides por HPLC em feijão / Development and validation of methodology for determination of pyrethroid pesticide residues by HPLC beans

Monteiro, Sérgio Henrique 13 September 2006 (has links)
Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras. / A rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 7 pyrethroid insecticides (bifenthrin, cypermethrin, fenpropathrin, fenvalerate, permethrin, lambda-cyhalothrin and deltamethrin) in beans. Residues are extracted from beans with acetone and the partition realized according to the multi-residue method DFG-S19, replacing dichloromethane by ethyl acetate/cyclohexane (1+1) and cleaned up using gel-permeation with a Biobeads SX3 column and ethyl acetate/cyclohexane (1+1) as eluant. LC separation is performed on a LiChrospher 100 RP-18 column with acetonitrile/water (8+2) as mobile phase. The pesticides are detected at 212 nm. Recoveries of 7 pyrethroid insecticides from beans fortified at 0.010; 0.100; 1.000 mg/kg levels were 71-105 %. The particular differential of this method is the quantification limits, which were between 0.004-0.011 mg/kg, lower than most of the limits reported for LC methods described in the literature. The gas chromatographic (GC) with electron capture detection is more sensitive than LC, but the LC method facilitates the identification of the peaks. Analysis of pyrethroids by GC shows several peaks, but LC shows only one for most pyrethroids. The analysis by LC was a good alternative for determination pyrethroid residues in beans. During 2005 year, a total of 48 bean samples commercialized in Sao Paulo City were analyzed. No residues of pyrethroids pesticides were detected in the samples.
32

Avaliação do emprego da técnica MEPS na análise de agrotóxicos em caldo de cana-de-açúcar por GC-MS / Evaluation of MEPS technique applied in pesticides analysis in sugarcane juice by GC-MS

Fumes, Bruno Henrique 12 February 2015 (has links)
O uso de técnicas miniaturizadas de preparo de amostra vem se tornando uma tendência cada vez mais crescente em química analítica. Dentre elas o MEPS (Microextraction by a Packed Sorbent) apresenta grande potencial por poder ser acoplado on-line, sem grandes modificações, à cromatografia gasosa e líquida, não necessitando de grande quantidade de tempo para análise e seu cartucho sorvente ser reutilizável. O uso de MEPS, foi mais explorado até o presente momento na análise de fármacos em fluídos biológicos; dessa forma existe um pequeno número de publicações que exploram o uso dessa técnica na determinação de agrotóxicos em matrizes de alimentos. Por esse motivo, o presente trabalho teve como objetivo a avaliação do uso dessa técnica na determinação de seis agrotóxicos utilizados no cultivo da cana-de-açúcar (tebutiurom, carbofurano, atrazina, metribuzim, ametrina e bifentrina) em amostras de garapa. Para o desenvolvimento desse estudo foram verificadas dentre as variáveis pH, força iônica, solvente de eluição e volume do solvente de eluição, quais poderiam afetar o desempenho da técnica em diferentes fases extratoras, empregando nessa etapa de otimização planejamento fatorial fracionário 24-1. As fases avaliadas foram C18 Chromabond e HLB Oasis, assim como sistemas comercialmente disponíveis com as fases C18, C8, SAX, SCX e SIL. Durante essa etapa foi realizado um estudo inicial do uso do grafeno como material sorvente em MEPS, considerando as propriedades que esse material apresenta para atuar como adsorvente em técnicas de preparo de amostra. Contudo, o uso do grafeno apresentou entupimento no cartucho de sorção, problema ainda em avaliação. A fase C18 Chromabond foi a que apresentou os melhores resultados, sendo a escolhida para otimização dos parâmetros envolvidos na etapa de extração por MEPS. Os parâmetros otimizados por planejamento fatorial 23 foram os ciclos de: aspiração da amostra, lavagem e eluição. O método desenvolvido foi validado baseado nos critérios exigidos pelo MAPA e apresentou seletividade, linearidade e os limites de quantificação variaram de 2-10 μg/L. A recuperação foi adequada para todos os analitos (71,7-106,9%), assim como a precisão intra e inter-dia que apresentou coeficientes de variação (CV) menores que 16%. O método desenvolvido foi aplicado em quatro amostras reais de garapa de diferentes regiões. / The use of miniaturized techniques in sample preparation has becoming a growing trend in analytical chemistry. Among these techniques MEPS (Microextraction by a Packed Sorbent) presents a great potential affording on-line coupling, without much modification to gas and liquid chromatography systems, in addition it does not require large analyses time and the sorbent cartridge is reusable. MEPS utilization has been explored mainly for drugs analyses in biological fluids, existing limited number of publications that apply this technique for pesticides analyses in food sample matrix. For this reason the goal of present work was the evaluation of MEPS in the analyses of six pesticides used in sugarcane cultivation (tebuthiuron, carbofuran, atrazine, metribuzine, ametryn and bifenthrin) in sugarcane juice samples. During the method development several variables were evaluated including pH, ionic strength, elution solvent and solvent volume, to determine which ones could affect the technique perform in different sorbent phases. For this optimization step, fractional factorial design 24-1 was utilized. Phases evaluated included C18 Chromabond and HLB Oasis, and also commercially available system containg C18, C8, SAX, SCX e SIL. During this step, it was also carried out an initial study employing graphene in a MEPS system; Tanking into account the properties that this material presents to act as adsorbent in sample preparation techniques. However the graphene showed obstruction problems in the sorption cartridge, whose solution is under way. The phase C18 Chromabond showed better results, and was chosen to MEPS parameters optimization. MEPs parameters optimized by full factorial desing 23 were the following cycles: sample aspiration, washing and elution. The method, was validated based upon the MAPA requirements and showed good selectivity, linearity an quantifications limits ranging from 2-10 μg/L. Recovery was satisfactory for all pesticides (71,7-106,9%), intra- and inter-day precision were satisfactory and showed coefficients of variation (CV) less than 16%. Hence, the developed method was applied to the analysis of four real samples of sugarcane juice obtained from different regions.
33

Određivanje sadržaja patulina u proizvodima od jabuka i procena izloženosti stanovništva patulinu / Determination of patulin in apple products and population exposure assessment

Dimitrov Nina 13 July 2018 (has links)
<p>Sprovedena studija po prvi put izve&scaron;tava o prisustvu patulina, sekundarnog metabolita određenih vrsta plesni, u proizvodima od jabuka, kao i proceni rizika usled unosa patulina od strane odojčadi, dece, adolescenata i odrasle populacije u Republici Srbiji. Ukupno 356 uzoraka sokova i ka&scaron;ica za odojčad i malu decu (48 i 66, redom), sokova za decu (mala pakovanja sa cevčicom, 100) i sokova u porodičnom pakovanju (142), sakupljeno je sa trži&scaron;ta tokom tri godine i analizirano primenom tečne hromatografije sa ultraljubičastom detekcijom, metodom koja je predhodno validirana. Prisustvo patulina je detektovano u 44% i 17% uzoraka sokova i ka&scaron;ica za odojčad i malu decu, redom, u količinama nižim od zakonskog ograničenja od 10 &mu;g/kg (maksimalno 8,3 i 7,7 &mu;g/kg, redom). Udeo kontaminiranih uzoraka među sokovima za decu iznosio je 43%, sa najvi&scaron;om koncentracijom patulina od 30,2 &mu;g/kg ispod maksimalno dozvoljenog nivoa od 50 &mu;g/kg. Patulin je detektovan u 51% sokova u porodičnom pakovanju, sa 0,7% uzoraka iznad zakonske granice od 50 &mu;g/kg (prosečna koncentracija 4,3 &mu;g/kg). Sokovi od jabuka su pokazali značajno vi&scaron;i udeo kontaminiranih uzoraka (74% u odnosu na 28%), kao i vi&scaron;i prosečni sadržaj patulina (6,4 u odnosu na 2,1 &mu;g/kg) u poređenju sa sokovima od me&scaron;anog voća. Procena rizika usled unosa patulina od strane odojčadi, dece, adolescenata i odrasle populacije u Republici Srbiji, sprovedena primenom determinističkog i probabilističkog pristupa, uključujući rezultate biodostupnosti patulina, pokazala je da je odnos između procenjenog dnevnog unosa i toksikolo&scaron;ke referentne doze za patulin od 0,4 &mu;g/kg telesne mase, koji se označava kao &ldquo;hazard quotient&rdquo;, znatno ispod 1, &scaron;to ukazuje na tolerantan nivo izloženosti i nepostojanje razloga za zabrinutost za zdravlje populacije. Dodatno, analiza ostataka pesticida i toksičnih metala potvrdila je bezbednost proizvoda od jabuka na trži&scaron;tu. Međutim, identifikacija vi&scaron;estrukih ostataka pesticida je razlog za aktivan pristup i pažljivo planiranje i sprovođenje monitoringa bezbednosti hrane, posebno hrane za odojčad i malu decu, kao najosetljivije populacione grupe.</p> / <p>This study reports for the first time the occurrence of patulin, a secondary metabolite of certain fungi, in apple-based food, as well as risk assessment related to patulin intake by infants, children, adolescents and adults in Serbia. In total, 356 samples of infant fruit juices (48), infant pur&eacute;e (66), juices for children (small package with straw, 100), and juices in family package (142) were collected from the market over three years (2013&ndash;15) and analysed using validated method based on liquid chromatography with ultraviolet detection. Patulin was found in 44% of infant juices and 17% of infant pur&eacute;e, with all values below the legal limit of 10 &mu;g/kg (maximum 8.3 and 7.7 &mu;g/kg, respectively). The proportion of contaminated samples among fruit juices for children was 43%, with the highest patulin concentration at 30.2 &mu;g/kg, not exceeding the maximum allowed level of 50 &mu;g/kg. Patulin was found in 51% of juices in family package, with 0.7% of the samples in excess of the legal limit of 50 &mu;g/kg (mean 4.3 &mu;g/kg). Apple juices showed significantly higher percentage of contaminated samples (74% versus 28%), as well as higher mean patulin content (6.4 versus 2.1 &mu;g/kg) when compared with the multifruit ones. Risk assessment of patulin intake by Serbian infants, children, adolescents and adults, conducted by deterministic and probabilistic approaches and including the bioaccessibility results, revealed a ratio between exposure and toxicological reference dose for patulin of 0,4 &mu;g/kg body weigth, called hazard quotients, well below 1, indicating a tolerable exposure level and no health concern. Furthermore, analysis of pesticide residues and toxic metals confirmed safety of apple products on the market. However, identification of multiple pesticide residues is a reason for an active attitude and carefully planned and conducted monitoring of food safety, expecialy in the case of food for infants and young children, as they are the most susceptible population group.</p>
34

Avaliação do emprego da técnica MEPS na análise de agrotóxicos em caldo de cana-de-açúcar por GC-MS / Evaluation of MEPS technique applied in pesticides analysis in sugarcane juice by GC-MS

Bruno Henrique Fumes 12 February 2015 (has links)
O uso de técnicas miniaturizadas de preparo de amostra vem se tornando uma tendência cada vez mais crescente em química analítica. Dentre elas o MEPS (Microextraction by a Packed Sorbent) apresenta grande potencial por poder ser acoplado on-line, sem grandes modificações, à cromatografia gasosa e líquida, não necessitando de grande quantidade de tempo para análise e seu cartucho sorvente ser reutilizável. O uso de MEPS, foi mais explorado até o presente momento na análise de fármacos em fluídos biológicos; dessa forma existe um pequeno número de publicações que exploram o uso dessa técnica na determinação de agrotóxicos em matrizes de alimentos. Por esse motivo, o presente trabalho teve como objetivo a avaliação do uso dessa técnica na determinação de seis agrotóxicos utilizados no cultivo da cana-de-açúcar (tebutiurom, carbofurano, atrazina, metribuzim, ametrina e bifentrina) em amostras de garapa. Para o desenvolvimento desse estudo foram verificadas dentre as variáveis pH, força iônica, solvente de eluição e volume do solvente de eluição, quais poderiam afetar o desempenho da técnica em diferentes fases extratoras, empregando nessa etapa de otimização planejamento fatorial fracionário 24-1. As fases avaliadas foram C18 Chromabond e HLB Oasis, assim como sistemas comercialmente disponíveis com as fases C18, C8, SAX, SCX e SIL. Durante essa etapa foi realizado um estudo inicial do uso do grafeno como material sorvente em MEPS, considerando as propriedades que esse material apresenta para atuar como adsorvente em técnicas de preparo de amostra. Contudo, o uso do grafeno apresentou entupimento no cartucho de sorção, problema ainda em avaliação. A fase C18 Chromabond foi a que apresentou os melhores resultados, sendo a escolhida para otimização dos parâmetros envolvidos na etapa de extração por MEPS. Os parâmetros otimizados por planejamento fatorial 23 foram os ciclos de: aspiração da amostra, lavagem e eluição. O método desenvolvido foi validado baseado nos critérios exigidos pelo MAPA e apresentou seletividade, linearidade e os limites de quantificação variaram de 2-10 &mu;g/L. A recuperação foi adequada para todos os analitos (71,7-106,9%), assim como a precisão intra e inter-dia que apresentou coeficientes de variação (CV) menores que 16%. O método desenvolvido foi aplicado em quatro amostras reais de garapa de diferentes regiões. / The use of miniaturized techniques in sample preparation has becoming a growing trend in analytical chemistry. Among these techniques MEPS (Microextraction by a Packed Sorbent) presents a great potential affording on-line coupling, without much modification to gas and liquid chromatography systems, in addition it does not require large analyses time and the sorbent cartridge is reusable. MEPS utilization has been explored mainly for drugs analyses in biological fluids, existing limited number of publications that apply this technique for pesticides analyses in food sample matrix. For this reason the goal of present work was the evaluation of MEPS in the analyses of six pesticides used in sugarcane cultivation (tebuthiuron, carbofuran, atrazine, metribuzine, ametryn and bifenthrin) in sugarcane juice samples. During the method development several variables were evaluated including pH, ionic strength, elution solvent and solvent volume, to determine which ones could affect the technique perform in different sorbent phases. For this optimization step, fractional factorial design 24-1 was utilized. Phases evaluated included C18 Chromabond and HLB Oasis, and also commercially available system containg C18, C8, SAX, SCX e SIL. During this step, it was also carried out an initial study employing graphene in a MEPS system; Tanking into account the properties that this material presents to act as adsorbent in sample preparation techniques. However the graphene showed obstruction problems in the sorption cartridge, whose solution is under way. The phase C18 Chromabond showed better results, and was chosen to MEPS parameters optimization. MEPs parameters optimized by full factorial desing 23 were the following cycles: sample aspiration, washing and elution. The method, was validated based upon the MAPA requirements and showed good selectivity, linearity an quantifications limits ranging from 2-10 &mu;g/L. Recovery was satisfactory for all pesticides (71,7-106,9%), intra- and inter-day precision were satisfactory and showed coefficients of variation (CV) less than 16%. Hence, the developed method was applied to the analysis of four real samples of sugarcane juice obtained from different regions.
35

From pesticide degradation products to legacy toxicants and emerging contaminants : novel analytical methods, approaches, and modeling

Forsberg, Norman D. 03 April 2014 (has links)
Environmental toxicologists and public health officials are responsible for assisting in the identification, management, and mitigation of public health hazards. As a result, there is a continued need for robust analytical tools that can aid in the rapid quantification and characterization of chemical exposure. In the first research phase, we demonstrated that a current tool for estimating human organophosphate pesticide exposure, measuring dialkyl phosphate (DAPs) metabolites in urine as chemical biomarkers of pesticide exposure, could represent exposure to DAPs themselves and not to pesticides. We showed that DAPs are metabolically stable, have high oral bioavailability, and are rapidly excreted in the urine following oral exposure. Results suggest that DAP measurements may lead to overestimates of human organophosphate pesticide exposure. In the second phase of research, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) based analytical method was developed and validated for quantifying polycyclic aromatic hydrocarbons (PAHs) in biotic matrices with fat contents that ranged from 3 to 11%. Our method improved PAH recoveries 50 to 200% compared to traditional QuEChERS methods, performed as well or better than state of the art Soxhlet and accelerated solvent extraction methods, had sensitivity useful for chemical exposure assessments, and reduced sample preparation costs by 10 fold. The validated QuEChERS method was subsequently employed in a human exposure assessment. Little is known about how traditional Native American fish smoke-preserving methods impact PAH loads in smoked foods, Tribal PAH exposure, or health risks. Differences in smoked salmon PAH loads were not observed between Tribal smoking methods, where smoking methods were controlled for smoking structure and smoke source. PAH loads in Tribally smoked fish were up to 430 times greater than those measured in commercially available smoked fish. It is not likely that dietary exposure to non-carcinogenic PAHs at heritage ingestion rates of 300 grams per day poses an appreciable risk to human health. However, levels of PAHs in traditionally smoked fish may pose and elevated of risk of cancer if consumed at high rates over a life time. Accurately estimating PAH exposure in cases where aquatic foods become contaminated is often hindered by sample availability. To overcome this challenge, we developed a novel analytical approach to predict PAH loads in resident crustacean tissues based on passive sampling device (PSD) PAH measurements and partial least squares regression. PSDs and crayfish collected from 9 sites within, and outside of, the Portland Harbor Superfund site captured a wide range of PAH concentrations in a matrix specific manner. Partial least squares regression of crayfish PAH concentrations on freely dissolved PAH concentrations measured by PSDs lead to predictions that generally differed by less than 12 parts per billion from measured values. Additionally, most predictions (> 90%) were within 3-fold of measured values, while state of the art bioaccumulation factor approaches typically differ by 5 to 15-fold compared to measured values. In order to accurately characterize chemical exposure, new analytical approaches are needed that can simulate chemical changes in bioavailable PAH mixtures resulting from natural and/or remediation processes. An approach based on environmental passive sampling and in-laboratory UVB irradiation was developed to meet this need. Standard PAH mixtures prepared in-lab and passive sampling device extracts collected from PAH contaminated environments were used as model test solutions. UV irradiation of solutions reduced PAH levels 20 to 100% and lead to the formation of several toxic oxygenated-PAHs that have been previously measured in the environment. Site specific differences in oxygenated-PAH formation were also observed. The research presented in this dissertation can be used to advance chemical exposure estimation techniques, rapidly and cost-effectively quantify a suite of PAHs in biotic tissues, and simulate the effect of abiotic transformation processes on the bioavailable fraction of environmental contaminants. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from April 3, 2013 - April 3, 2014
36

Valutazione dell'esposizione del consumatore a resdui di pesticidi negli alimenti: stato attuale e prospettive future in Lombardia / Consumers exposure assessment of pesticide residues in food: current status and future perspective in Lombardy

CHIODINI, ALESSANDRO MARINO 24 February 2011 (has links)
La presente tesi descrive i risultati del programma di controllo dei pesticidi in regione Lombardia da 1996 a 2008 ed analizza i dati per calcolarne, con metodi diversi, la valutazione dell’esposizione del consumatore. 9387 campioni sono stati analizzati con un numero di campioni irregolari pari all’1%. Il numero di campioni senza residuo era pari al 69% ed il numero di campioni con i residui al di sotto del valore limite stabilito per legge era del 30%. Successivamente per capire l'esposizione dei consumatori a residui di antiparassitari si è utilizzato un metodo deterministico sviluppato da EFSA (PRIMo). È stato trovato che fra i campioni irregolari analizzati, solo 31 potrebbero causare il danno alla salute del consumatore. Un’ ulteriore analisi è stata quella di effettuare una valutazione con metodo probabilistico (Creme) calcolando l'esposizione cumulativa di antiparassitari sulla salute dei consumatori. Coem primo passo, residui di uno stesso pesticida trovato su campioni di patate sono stati inseriti nel software. Inoltre, campioni contenenti residui di pesticidi organofosfati sono stati inseriti nel software accoppiati con i dati italiani di consumo. In entrambi i casi, la valutazione cumulativa probabilistica dimostrava un adeguato livello di sicurezza per adulti e bambini. / The presented thesis describes the results of the pesticide monitoring programme in Lombardy Region from 1996 to 2008 and analyses the data gathered to calculate consumer exposure assessment with different approaches. A total of 9387 samples were analysed and the number of irregular samples was equal to 1%. The number of samples without residues was 69% and the number of samples with residues within the MRL was 30%. A further step to understand the exposure of consumers to residue of pesticides was obtained with the use of a deterministic approach developed by EFSA (PRIMo Model). It was found that among the detected irregular samples, only 31 might cause harm to the health of the consumer. An additional step was constituted by the use of one probabilistic method (Creme Software) to calculate the cumulative exposure of pesticides for the consumers. As a first step, residues of Chlorprofam were plotted in the software on samples of potato. In addition, samples containing residues of Organophosphates were also plotted along with the Italian consumption data. In both the case studies, the probabilistic acute cumulative assessment indicated that the intake, for adults and toddlers was below the set toxicological endpoint.
37

The History of International Food Safety Standards and the Codex alimentarius (1955-1995)

Ramsingh, Brigit Lee Naida 19 November 2013 (has links)
Following the Second World War, the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) teamed up to construct an international Codex Alimentarius (or “food code”) in 1962. Inspired by the work of its European predecessor, the Codex Europaeus, these two UN agencies assembled teams of health professionals, government civil servants, medical and scientific experts to draft food standards. Once ratified, the standards were distributed to governments for voluntary adoption and implementation. By the mid-1990s, the World Trade Organization (WTO) identified the Codex as a key reference point for scientific food standards. The role of science within this highly political and economic organization poses interesting questions about the process of knowledge production and the scientific expertise underpinning the food standards. Standards were constructed and contested according to the Codex twin goals of: (1) protecting public health, and (2) facilitating trade. One recent criticism of Codex is that these two aims are opposed, or that one is given primacy over the other, which results in protectionism. Bearing these themes in mind, in this dissertation I examine the relationship between the scientific and the ‘social’ elements embodied by the Codex food standards since its inception after the Second World War. I argue that these attempts to reach scientific standards represent an example of coproduction– one in which the natural and social orders are produced alongside each other. What follows from this central claim is an attempt to characterize the pre-WTO years of the Codex through a case study approach. The narrative begins with a description of the predecessor regional group the Codex europaeus, and then proceeds to key areas affecting human health: 1) food additives, 2) food hygiene, and 3) pesticides residues.
38

Desenvolvimento e validação de metodologia para determinação de resíduos de pesticidas piretróides por HPLC em feijão / Development and validation of methodology for determination of pyrethroid pesticide residues by HPLC beans

Sérgio Henrique Monteiro 13 September 2006 (has links)
Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras. / A rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 7 pyrethroid insecticides (bifenthrin, cypermethrin, fenpropathrin, fenvalerate, permethrin, lambda-cyhalothrin and deltamethrin) in beans. Residues are extracted from beans with acetone and the partition realized according to the multi-residue method DFG-S19, replacing dichloromethane by ethyl acetate/cyclohexane (1+1) and cleaned up using gel-permeation with a Biobeads SX3 column and ethyl acetate/cyclohexane (1+1) as eluant. LC separation is performed on a LiChrospher 100 RP-18 column with acetonitrile/water (8+2) as mobile phase. The pesticides are detected at 212 nm. Recoveries of 7 pyrethroid insecticides from beans fortified at 0.010; 0.100; 1.000 mg/kg levels were 71-105 %. The particular differential of this method is the quantification limits, which were between 0.004-0.011 mg/kg, lower than most of the limits reported for LC methods described in the literature. The gas chromatographic (GC) with electron capture detection is more sensitive than LC, but the LC method facilitates the identification of the peaks. Analysis of pyrethroids by GC shows several peaks, but LC shows only one for most pyrethroids. The analysis by LC was a good alternative for determination pyrethroid residues in beans. During 2005 year, a total of 48 bean samples commercialized in Sao Paulo City were analyzed. No residues of pyrethroids pesticides were detected in the samples.
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QUALIDADE DO LEITE PRODUZIDO EM SISTEMAS ORGÂNICO E CONVENCIONAL / QUALITY OF MILK PRODUCED IN ORGANIC AND CONVENTIONAL SYSTEMS

Granella, Vanusa 27 November 2013 (has links)
The concern about food safety, animal welfare, and environmental impacts caused by intensive production systems has led to an increasing interest in foods derived from a sustainable production system. In this context, organic milk production in Brazil has grown considerably in recent years, but little is known about the quality of the food produced in the country. In order to evaluate the quality of organic milk, the hygienic quality, chemical composition, and safety concerning pesticide residues was assessed. Five brands of certified organic pasteurized milk and five brands of conventional pasteurized milk commercialized in three Brazilian states were collected between May 2011 and March 2012, every two months, totaling 29 samples of organic milk (OM) and 27 conventional milk (CM). The collection of raw milk samples was made every two months, from July 2011 to May 2012 in 20 organic farms and 20 conventional farms in western Santa Catarina, totaling 120 OM and 115CM samples. In pasteurized milk, physicochemical analyzes were performed and the fatty acid profile was determined. In raw milk, chemical composition analyzes, somatic cell count (SCC), and total bacterial count (TBC) were carried out. Both types of milk were subjected to the determination of pesticides and veterinary drugs. When the results of raw milk production in the two systems were compared, no difference for the mean value of fat, protein and total solids, or SCC was found. Organic milk showed better quality in relation to microbial contamination and higher content of lactose. For pasteurized milk with the exception of non fat solids, all average values of physical and chemical parameters of milk met the limits of the Brazilian legislation. The fatty acid profile was affected by geographical origin, and to a lesser extent, the effect of season, probably due to differences on the feeding regime. The milk obtained in Rio Grande do Sul and São Paulo were characterized by having higher values of health-promoting fatty acids, including conjugated linoleic acid (CLA). However, the milk collected in the Federal District was characterized by higher concentrations of saturated fatty acids (SFA). The results for raw and pasteurized milk indicate that the organic management alone had no effect on milk quality regarding chemical composition, which are determined by several factors that are independent of the production system. No veterinary drugs was found in any of the samples analyzed. However, for contamination with pesticides no difference was observed when considering the number of contaminated samples in either production system. Results indicate the need to monitor milk for the presence of pesticides in order to improve food safety, especially for organic milk, which should be free of such contaminants. / A preocupação com segurança alimentar, bem-estar animal e impactos no meio ambiente causados pelos sistemas intensivos de produção, tem levado a um maior interesse por alimentos que sejam oriundos de um sistema de produção sustentável. Neste contexto, a produção de leite orgânico no Brasil cresceu consideravelmente nos últimos anos, porém pouco se sabe sobre a qualidade deste alimento produzido no país. Para avaliar a qualidade do leite orgânico foram realizadas análises que contemplaram aspectos da qualidade higiênica, composição química e a segurança quanto à presença de resíduos químicos. Cinco marcas de leite orgânico pasteurizado certificado e cinco de leite pasteurizado convencional comercializados em três Estados brasileiros foram coletadas entre maio de 2011 e março de 2012, com intervalo de dois meses, totalizando 29 amostras de leite orgânico (LO) e 27 de leite convencional (LC). As coletas de leite cru foram feitas de julho de 2011 a maio de 2012, também bimestrais, em 20 propriedades orgânicas e 20 propriedades convencionais na região Oeste de Santa Catarina, totalizando 120 amostras de LO e 115 de LC. No leite pasteurizado foram realizadas análises físico-químicas e o perfil de ácidos graxos. No leite cru foram realizadas as análises de composição química, contagem de células somáticas (CCS) e contagem bacteriana total (CBT). Ambos os tipos de leite foram submetidos à determinação de agrotóxicos e medicamentos veterinários. Comparando-se os resultados do leite cru, entre os dois sistemas de produção, não foi encontrado diferença para o valor médio de gordura, proteína e sólidos totais, assim como para CCS. O leite orgânico apresentou melhor qualidade em relação a contaminação microbiana e teor superior de lactose. Para o leite pasteurizado com exceção do extrato seco desengordurado (ESD), todos os valores médios dos parâmetros físicos e químicos atenderam aos limites da legislação brasileira. O perfil de ácidos graxos sofreu efeito da origem geográfica, e em menor escala o efeito da sazonalidade, provavelmente por diferenças no regime alimentar. Os leites obtidos no Rio Grande do Sul e em São Paulo se caracterizaram por possuir valores superiores de ácidos graxos promotores da saúde, entre eles o ácido linoléico conjugado (CLA), enquanto os leites coletados no Distrito Federal se caracterizaram por concentrações superiores de ácidos graxos saturados. Os resultados para o leite cru e pasteurizado indicam que o manejo orgânico por si só, não influenciou na qualidade do leite quanto aos aspectos de composição química, que são determinados por vários fatores que independem do sistema de produção. Não foram encontrados medicamentos veterinários em nenhuma das amostras analisadas. Quanto à contaminação por agrotóxicos não houve diferença quando considerado o número de amostras contaminadas em ambos os sistemas de produção. Os resultados indicam a necessidade de monitorar o leite quanto a presença de agrotóxicos a fim de melhorar a segurança alimentar, principalmente para leite orgânico, que deve estar livre desse tipo de contaminantes.
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Surveillance des expositions alimentaires aux résidus de pesticides : développement d’une méthode globale d’appréciation quantitative du risque pour optimiser l’évaluation et la gestion du risque sanitaire / Monitoring of dietary exposure to pesticide residues : development of a method of quantitative risk assessment to optimize the evaluation and management of health risks

Nougadère, Alexandre 15 June 2015 (has links)
L'évaluation des produits phytopharmaceutiques, leur mise sur le marché et la surveillance des résidus de pesticides dans les aliments sont harmonisés au niveau européen. Les estimations des expositions alimentaires a posteriori réalisées en Europe sont cependant incomplètes au regard du nombre de denrées et de pesticides évalués, et les données de consommation utilisées sont souvent anciennes. L’amélioration des connaissances sur les risques alimentaires liés aux pesticides constitue l’un des enjeux majeurs de santé publique. L’objectif de cette thèse est de construire un système national de surveillance a posteriori des expositions et des risques alimentaires afin de guider (1) d’une part les gestionnaires du risque dans le cadre de l’élaboration de leurs programmes de surveillance et des mesures préventives et correctives ; (2) d’autre part les évaluateurs du risque dans l’orientation des travaux de recherche et d’expertise en métrologie, expologie et toxicologie. Ce système de surveillance comprend deux outils complémentaires : (1) une méthode d’appréciation quantitative du risque dite « globale » basée sur quatre indicateurs chroniques et aigus actualisés annuellement à partir des résultats des derniers plans de surveillance et des limites maximales de résidus ; (2) des études pluriannuelles dites études de l’alimentation totale (EAT) dont la première EAT française sur les pesticides. Ces deux approches sont basées sur les données de l’étude individuelle et nationale des consommations alimentaires Inca 2 de l’Anses. La méthode globale annuelle intègre une échelle de priorités ayant permis de hiérarchiser les risques pour 519 pesticides. Les niveaux d’exposition estimés dans l’EAT2 sont globalement plus réalistes que ceux issus de la méthode annuelle. Cependant, les deux outils n’ont pas permis initialement d’affiner suffisamment l’évaluation pour certains pesticides. Par conséquent, la méthode a été ajustée afin de mieux gérer les résultats d’analyse censurés. Après ajustement, 14% des pesticides sont identifiés comme prioritaires en termes d’évaluation et/ou de gestion du risque (niveaux 2 à 6), compte tenu de dépassements des valeurs toxicologiques de référence. A partir des couples prioritaires pesticide/denrée, un plan d’échantillonnage est défini pour les prochains plans de surveillance. Des mesures de gestion correctives et une intensification des contrôles à la production et à la distribution sont recommandés pour 11 pesticides de niveau de risque maximal (niveau 6) en lien avec 16 couples pesticide/denrée. Au final, ce système national est plus complet et plus adapté à la population française que l’évaluation communautaire annuelle. Les résultats obtenus sont par ailleurs cohérents avec ceux de la première étude nationale de biosurveillance sur les pesticides. Enfin, la méthode globale annuelle intégrera les évolutions méthodologiques communautaires récentes pour l’évaluation des risques cumulés. / The evaluation of plant protection products, their marketing and the monitoring of pesticide residues in food are harmonized in the European Union. Nevertheless, the assessment of dietary exposure at post-regulation level is incomplete due to the small number of foods and pesticides taken into account. In addition, consumption data are often obsolete. Improving knowledge on the dietary risk of pesticide residues is one of the major challenges to public health. The aim of this thesis is to build a national system for the ex post monitoring of dietary exposure and risk to the general population in order to guide (1) risk managers in the development of their monitoring programmes and preventive and corrective measures; (2) risk assessors in guiding research and expertise in metrology, exposure assessment and toxicology. This monitoring system includes two complementary tools: (1) an annual method of quantitative risk assessment based on four chronic and acute indicators updated each year and based on the results of the latest monitoring plans and maximum residue levels; (2) multi-year total diet studies (TDS), including the first TDS on pesticide residues (TDS2). These two approaches are based on the results of ANSES’s INCA2 individual and national consumption survey. This annual method includes a 6-level risk scale that enables the prioritization of risk for 519 pesticides. The exposure levels estimated in TDS2 are in general more realistic than those of the annual method. However, for certain pesticides it was not possible to sufficiently refine exposure levels using these two tools. Consequently, the annual method was adjusted to improve management of left-censored analytical results. After adjustment, 14% of pesticides were identified as a priority in terms of risk assessment and/or risk management (levels 2 to 6), given that they exceeded the toxicological reference values. Based on priority pesticide/foodstuff pairs, a sampling plan has been established for subsequent monitoring programmes. Corrective management measures and intensified controls of production and distribution are recommended for 11 pesticides scored at maximal risk level (level 6) in association with 16 pesticide/foodstuff pairs. In the end, this national system is more comprehensive and better suited to the French population than the annual EU assessment. The results are also consistent with those of the first national biomonitoring study on pesticides. The annual method will also incorporate recent European methodological developments for cumulative risk assessment.

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