Thesis (M.Sc.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: p.105-126.

A five-year study was carried out to test a sensitive, nondestructive, new method for determining sublethal and long-term consequences of fenitrothion applications on forest songbirds. I used censuses and territory mapping of singing males to provide indices of relative abundance on sprayed and control plots. Mist-netting was used to colour-band individuals of 3 indicator species (the chestnut-sided warbler, magnolia warbler and white-throated sparrow), to determine "their breeding condition, and to follow their fates after a fenitrothion application. Time-budget observations were made of the behaviour of some marked individuals. Fenitrothion was applied aerially in 1985, and by ground in 1986. I first studied the effect of fenitrothion on the songbird community; comparing treatment and control plots, before and after the application. Data on the bird populations showed that fewer young were caught in 1985, and birds returned at a lower rate the year following treatment; a lower proportion of the 1986 catch in mist nets were males. Nonetheless, other factors (budworm cycles, for example) had a greater influence on population trends than the treatment. Behavioural observations indicated that individuals of the 3 indicator species did not abandon the treated area after either application, although white-throated sparrows and magnolia warblers moved away from foliage regions with higher deposits of spray. There was no significant change in the allotment of time to social, maintenance, or feeding behaviours, for any of the indicator species. This observation is not consistent with the known symptoms of organophosphate poisoning (i.e. increased time spent sitting, bill-wiping, and preening). Chestnut-sided warblers and white-throated sparrows continued to forage actively on sprayed plots or nearby. Magnolia warblers decreased their foraging effort after both applications. In part 2 of the thesis, I studied the effect of fenitrothion on the invertebrate food of forest songbirds. Branch samples were taken as a measure of the food available to foliage-gleaning birds. Drop trays were placed under sample trees to measure the amount of food fallen from the tree after the application. Following treatment, there was a lower density of invertebrates on white birch and balsam fir branches than on control trees. This reduction was not observed until 5 days after the application, although drop tray samples indicated an immediate kill of invertebrates. These techniques sampled different types of invertebrates such that a large proportion of the drop tray samples were not associated with the tree (eg. flying Diptera). In addition to a decreased abundance, a large portion of the remaining invertebrates on white birch treated trees were dead. This suggests a further decrease in food availability to birds like warblers that specialize on moving prey. The depression of food available to birds was probably short-lived, assuming movement of invertebrates into depopulated areas from unsprayed foliage nearby. Behavioural responses of birds to spraying were also short-lived, apparent only within 5 days of the application. At the maximum allowable single dose, fenitrothion appears to have little effect on forest songbirds, even when tested with a highly-sensitive method. / Science, Faculty of / Zoology, Department of / Graduate

Orientador: Susanne Rath / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-16T00:51:54Z (GMT). No. of bitstreams: 1 Barros_LeonardoAugustode_M.pdf: 2516979 bytes, checksum: 9e6340ca4d81c25d9929cae4417e6fbf (MD5) Previous issue date: 2010 / Resumo: Esse trabalho teve como objetivo principal sintetizar um polímero de impressão molecular (MIP) para ser empregado em processo de extração em fase sólida (SPE), visando a determinação de resíduos de fenitrotiona (FNT) em tomates. Os reagentes da síntese foram selecionados a partir de estudos de modelagem molecular, usando para tanto o programa computacional Gaussian 03. As energias eletrônicas de ligação para a interação entre o monômero funcional e a FNT, no vácuo e no solvente, foram calculadas através do método DFT, no nível B3LYP e conjunto de base 6-31G(d). Os reagentes de síntese foram: FNT (molde), ácido metacrílico (monômero funcional), etilenoglicol dimetacrilato (reagente de ligação cruzada), AIBN (iniciador radicalar) e tolueno (solvente porogênico). Também foi sintetizado um polímero não-impresso (NIP). Por meio de estudos de adsorção foi avaliado o meio de melhor reconhecimento molecular. Foram construídas as isotermas de adsorção para cada um dos polímeros impresso e não impresso e foi avaliada a seletividade do MIP frente a análogos da FNT. Os polímeros foram caracterizados por infravermelho com transformada de Fourier, ressonância magnética nuclear de C, microscopia de varredura eletrônica e porosimetria de sorção de nitrogênio (BET). O MIP foi empregado como fase estacionária em SPE. Foi desenvolvido e validado um método para a determinação de FNT em tomates, usando a cromatografia líquida de alta eficiência. A eficiência de extração foi de 96%. A faixa linear foi de 130 a 2000 ng g, com uma linearidade superior a 0,99. A precisão intra-ensaio e inter-ensaio foram inferiores a 7,0% e 8,1%, respectivamente (níveis de fortificação 250, 500 e 1000 ng g). A exatidão foi superior a 89% no nível de fortificação em torno do limite máximo de resíduo de 500 ng g / Abstract: This work aimed the synthesis of a molecularly imprinted polymer (MIP) to be employed in process of solid phase extraction (SPE), for the determination of residues of fenitrothion (FNT) in tomatoes. The synthesis reagents were selected from molecular modeling, using the Gaussian 03 software. The electronic binding energies for the interaction between the functional monomer and the FNT, in vacuum and in solvent, were calculated by the DFT method in B3LYP level and 6-31G(d) basis set. The reagents of the synthesis were: FNT (template), methacrylic acid (functional monomer), ethyleneglycol dimethacrylate (cross-linker), AIBN (initiator) and toluene (porogenic solvent). Also, was synthesized a non-imprinted polymer. Through batch rebinding studies were evaluated the medium of the best molecular recognition. The adsorption isotherms for each imprinted and non-imprinted polymer were constructed and the selectivity of the MIP in relation to FNT analogues evaluated. The polymers were characterized by Fourier transform infrared, C nuclear magnetic resonance, scanning electron microscopy and nitrogen sorption porosimetry (BET). The MIP was employed as stationary phase in SPE. A method for the determination of FNT in tomatoes was developed and validated, using high performance liquid chromatography. The extraction efficiency was 96%. The linear range was 130 to 2000 ng g, with a linearity greater than 0.99. The intra-day and inter-day precision were lower than 7.0% and 8.1%, respectively (fortification levels 250, 500 e 1000 ng g). The accuracy was higher than 89% for a concentration level around the maximum residue limit of 500 ng g / Mestrado / Quimica Analitica / Mestre em Química

Orientador: Susanne Rath / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-10T22:20:57Z (GMT). No. of bitstreams: 1 Pereira_LeandroAlves_M.pdf: 1182437 bytes, checksum: 9e5bb63e48650f93fbbd8632bfc95f93 (MD5) Previous issue date: 2008 / Resumo: Resíduos de agrotóxicos presentes em alimentos podem exceder os limites máximos de resíduos, quando as boas práticas agrícolas não são respeitadas. Conseqüentemente, a determinação dos resíduos de agrotóxicos é extremamente importante para avaliar o uso apropriado dessas substâncias e os riscos à saúde humana decorrentes da sua presença nos alimentos. A determinação de resíduos de agrotóxicos em alimentos requer etapas de preparo de amostras que consistem, geralmente de etapas de extração, remoção de interferentes e concentração do analito anterior análise cromatográfica. Para tanto, tem sido largamente empregada a extração em fase sólida. O objetivo do presente trabalho foi a síntese e caracterização de polímeros de impressão molecular (MIP) para uso em cartuchos de extração em fase sólida, visando a determinação de fenitrotiona (FNT) em tomates. O polímero foi sintetizado a partir do ácido metacrílico (monômero funcional), etileno glicoldimetilacrilato (reagente de ligação cruzada), 2'2azo-bis-iso-butironitrila (iniciador radicalar) em diclorometano (solvente porogênico), usando a FNT como molécula molde. Também foi sintetizado um polímero de controle (NIP). O MIP foi caracterizado por técnicas de infravermelho de transformada de Fourier, ressonância magnética nuclear do estado sólido, microscopia de varredura eletrônica e porosimetria de sorção de nitrogênio. O modelo de Langmuir-Freundlich foi o que apresentou o melhor ajuste para descrever a adsorção da FNT no polímero. O MIP foi empregado em cartuchos de extração em fase sólida e as etapas de condicionamento, carregamento, lavagem e eluição otimizadas. A extração em fase sólida molecularmente impressa foi aplicada na determinação de FNT em amostras de tomates, usando a cromatografia líquida de alta eficiência associada a um detetor de arranjo de diodos. A eficiência de extração, para amostras branco de tomates fortificadas com 5mg g de FNT, foi de 65 %. Nenhum interferente foi observado nos cromatogramas no tempo de retenção da FNT, indicando a seletividade do polímero / Abstract: Pesticide residues present in food can exceed maximum residue level when good agricultural practices are not followed. Consequently, the determination of pesticide residues is extremely important to evaluate the appropriate use of theses substances and risks to human health due to their presence in food. The determination of pesticide residues in food requires sample preparation steps that consist mainly of extraction, clean-up, and concentration of the analyte prior to chromatographic quantitation.. For this purpose, solid-phase extraction has been widely employed. The aims of this work were the synthesis and characterization of a molecularly imprinted polymer (MIP) to be employed as a sorbent in solid phase extraction cartridges for the determination of fenitrothiom (FNT) in tomatoes. The polymer was synthesized using FNT as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linking monomer, and 2,2-azobis-isobutyronitrile as the initiator. Dichloromethane was used as the porogenic solvent. Also, a non-imprinted polymer was synthesized. The MIP was characterized using the following techniques: FT-IR, NMR, electronic microscopy and BET. The adsorption of FNT on the polymer was fitted to the Langmuir-Freundlich model. The polymer was used in the solid-phase extraction cartridges and the conditioning, sample loading, clean-up and elution steps were optimized. The molecularly imprinted solid phase extraction was used for the determination of FNT in tomatoes, using high performance liquid chromatography with a diode array detector. For extraction efficiency, for a fortified blank tomato sample (5 mg g FNT), was 65 %. No interferences were observed in the chromatograms at the retention time of FNT, indicating the selectivity of the polymer / Mestrado / Quimica Analitica / Mestre em Química