Na busca por compostos voláteis para utilização no manejo comportamental de Diaphorina citri Kuwayama (Hemiptera: Liviidae), a resposta destes insetos foi avaliada frente às substâncias liberadas por plantas de laranja, Citrus sinensis (L.) Osbeck, variedade \'Pêra\', enxertadas sobre limão-cravo, C. limonia Osbeck, sadias vs sintomáticas para Huanglongbing (HLB). Voláteis destas plantas, bem como seus extratos foram testados em olfatômetro \'Y\' e analisados por GC-MS. Somente fêmeas foram atraídas, tanto para os voláteis quanto para os extratos, e preferencialmente os de plantas doentes. Foram encontrados 47 compostos em extratos de plantas sadias e doentes, dos quais 11 [hexanal; α-tujeno; α-pineno; sabineno; β-mirceno; α-terpineno; limoneno; linalol; composto 37 (não identificado); β-elemeno e β-copaeno] presentes em maior quantidade nos extratos de plantas doentes, sendo que 3 desses compostos (sabineno, linalol e β -elemeno) foram majoritários nos extratos de ambas as plantas, doentes e sadias. Esses três compostos, bem como uma substância padrão para atração (salicilato de metila), foram testados em diferentes concentrações e misturas em laboratório, casa-de-vegetação e campo. O efeito destas substâncias foi dependente de sua concentração e, embora limoneno tenha alterado a resposta comportamental das fêmeas, apenas salicilato de metila e linalol foram atraentes. Em laboratório, a mistura desses dois compostos apresentou efeito sinérgico na atração de fêmeas e, em casa-de-vegetação, a adição de linalol junto a plantas de citros aumentou a atratividade das mesmas para insetos adultos, sugerindo importante participação desses compostos no processo de seleção hospedeira pelo inseto. Estes resultados acrescentam novas informações para a busca de um atraente para D. citri visando o manejo comportamental do inseto vetor das bactérias Liberibacter, associadas ao HLB, a mais importante doença dos citros no mundo. / With the aim of searching for volatile compounds to use in behavioral management of Diaphorina citri Kuwayama (Hemiptera: Liviidae), the response of these insects was assessed against the substances released by sweet orange [Citrus sinensis (L.) Osbeck], variety \'Pera\', grafted on Rangpur (C. limonia Osbeck), healthy and Huanglongbing (HLB) symptomatic plants. Plant volatiles as well as plant extracts were tested in Y-tube olfactometer assays and analyzed by GC-MS. Only females were attracted to plant volatiles and extracts and they preferred those from HLB-infected plants. A total of 47 compounds was found in the extracts from healthy and infected plants, from which 11 [hexanal; α-thujene; α-pinene; sabinene; β- myrcene; α-terpinene; limonene; linalool; compound #37 (not identified); β-elemene; and β-coapene] were present in higher amounts in infected plant extracts. Three of these volatiles (sabinene, linalool and β-elemene) represented major compounds in both infected and healthy plant blend extracts. These three compounds, as well as a standard substance used for attraction (methyl salicylate), were tested in different concentrations and mixtures in laboratory, greenhouse and field. The effect of these substances was dependent on its concentration and, although limonene changed female behavioral response, only methyl salicylate and linalool were attractive. In the laboratory, the mixture of these two compounds showed a synergistic effect in attracting females and, in greenhouse, the addition of linalool to citrus plants increased the attractiveness of plants to adult insects, suggesting an important role for these compounds in the host selection process by the insect. These results provide novel information about attractants to D. citri with the aim of developing a behavioral management approach of the insect vector for Liberibacter, bacteria associated to HLB, the most important citrus disease worldwide.

O arbusto Heterothalamus psiadioides Less. (Asteraceae) ocorre no sul do Brasil e no Uruguai, se estabelecendo frequentemente em formações densas. Esse padrão de estabelecimento pode estar relacionado a efeitos alelopáticos dos voláteis liberados por essa planta. Portanto, este trabalho objetivou investigar os efeitos do óleo essencial de H. psiadioides sobre a germinação, crescimento inicial, enraizamento adventício e desenvolvimento vegetativo e reprodutivo de Arabidopsis thaliana (L.) Heynh., planta-alvo desse estudo. Além disso, a caracterização química do óleo essencial foi realizada. Para avaliar efeitos sobre a germinação e o crescimento inicial, sementes e plântulas de A. thaliana foram expostas aos voláteis de H. psiadioides, cuja composição química foi analisada através de cromatografia em fase gasosa associada à espectrometria de massas. Para avaliar efeitos sobre o enraizamento adventício, plântulas de A. thaliana tiveram suas raízes primárias cortadas, gerando microestacas que foram expostas aos voláteis. Além disso, tratamentos para recuperação dos efeitos causados pelos voláteis foram utilizados – com adição de auxina, citocinina e antioxidante ao meio de cultura. No experimento que testou os efeitos dos voláteis sobre o desenvolvimento reprodutivo e vegetativo da planta-alvo, as plantas foram expostas aos voláteis dentro de câmaras de vidro. Após a exposição e quando as plantas senesceram, parâmetros vegetativos e reprodutivos foram avaliados. A germinação e o crescimento inicial da planta-alvo foram afetados negativamente pelos voláteis de H. psiadioides. Da mesma forma, o enraizamento adventício das plantas foi afetado. Microestacas da planta-alvo expostas aos voláteis demoraram mais tempo para enraizar, desenvolveram menos raízes e essas eram mais curtas do que as microestacas controle. Estresse oxidativo foi detectado nas microestacas expostas aos voláteis; além disso, hormônios e antioxidante não reverteram os efeitos fisiológicos negativos causados pelos mesmos. A avaliação do desenvolvimento vegetativo e reprodutivo das plantas expostas aos voláteis nas câmaras de vidro permitiu detectar efeitos negativos dos voláteis apenas em um parâmetro relacionado ao crescimento, que foi mensurado logo após o período de exposição. Nenhum outro parâmetro diferiu significativamente entre plantas expostas aos voláteis e não expostas. Esses resultados indicam que apesar dos drásticos efeitos demonstrados pelos voláteis sobre sementes e plântulas, efeitos pouco relevantes foram encontrados para o desenvolvimento vegetativo e reprodutivo. Portanto, possivelmente o potencial alelopático de H. psiadioides pode ser menor do que o esperado, já que plantas juvenis a adultas são capazes de recuperar-se dos efeitos dos voláteis dessa planta. / The shrub Heterothalamus psiadioides Less. (Asteraceae) occurs in Southern Brazil and Uruguay, where it often establishes in dense populations. This pattern of establishment may be related to allelopathic effects of the volatiles released by this plant. Therefore, this study aims to investigate the effects of the volatile essential oil of H. psiadioides on germination, early growth, adventitious rooting and vegetative and reproductive development of Arabidopsis thaliana (L.) Heynh., the target plant of this study. Furthermore, the chemical characterization of the essential oil was performed. To assess effects on germination and early growth, seeds and seedlings of A. thaliana were exposed to H. psiadioides volatiles, which had the chemical composition analyzed by gas chromatography coupled to mass spectrometry. To evaluate effects on adventitious rooting, seedlings of A. thaliana had the primary roots excised, generating microcuttings that were exposed to the volatiles. Moreover, treatments to recovery the effects caused by the volatiles were used – with addition of auxin, cytokinin and antioxidant in the culture medium. In the experiment that tested the effects of the volatiles on the vegetative and reproductive development of the target plant, plants were exposed to the volatiles inside of glass chambers. After the exposition and at senescence, vegetative and reproductive parameters were evaluated. The germination and early growth were negatively affected by the volatiles. Adventitious rooting was similarly affected. Microcuttings of the target plant exposed to the volatiles were slower to root, less developed and had shorter roots in relation to control microcuttings. Oxidative damage was detected in the microcuttings exposed to the volatiles; furthermore hormones and antioxidant did not revert negative physiological effects caused by the oil. The evaluation of vegetative and reproductive development of plants exposed to the volatiles inside of glass chambers allowed to detect negative effects just in a parameter measured immediately after removal plants from the chambers. Other parameters did not differ between plants exposed to the volatiles and plants not exposed. These results indicate that despite of drastic effects showed by the volatiles on seeds and seedlings, effects of little relevance were found in vegetative and reproductive development. Therefore, it is possible that allelopathic potential of H. psiadioides may be lower than expected, since juvenile and adult plants are able to recover from the effects of the plant volatiles.

Orientador: Fabio Augusto / Tese (doitorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T06:52:57Z (GMT). No. of bitstreams: 1 Silva_AnaClaudiaLemesda.pdf: 2973527 bytes, checksum: 8d640c252ae8364f2e60128332ab484c (MD5) Previous issue date: 2006 / Resumo: O mel é uma das misturas mais complexas de carboidratos produzida pela natureza. É um alimento energético muito importante pelas suas propriedades nutritivas, pelo seu aroma e sabor que dependem fortemente das plantas, flores e condições climáticas presentes na região geográfica onde está localizada a colméia. Não existem metodologias que possibilitem identificação não subjetiva, rápida e confiável da origem floral do mel. O objetivo deste trabalho foi desenvolver uma metodologia que permitisse a identificação da origem floral de méis brasileiros a partir da caracterização química de sua fração de voláteis utilizando micro-extração em fase sólida através do headspace e cromatografia gasosa (HS-SPME-CG). Para o desenvolvimento da metodologia, foram avaliadas 90 amostras de méis brasileiros de vinte origens florais diferentes e variadas procedências geográficas. Onze destas amostras eram unitárias e permitiram apenas um estudo exploratório. Cada tipo de mel apresentou um perfil cromatográfico diferente. Foram identificados potenciais marcadores para os méis de eucalipto (Eucalyptus sp), laranja (Citrus sp), assa-peixe (Vernonia polianthes), cambará (Lantana montevidensis), morrão de candeia (Croton sp) e marmeleiro (Cydonia vulgaris). Os resultados obtidos mostraram que SPME-CG é útil na tipificação de méis e pode eventualmente ser utilizada na sua certificação / Abstract: Honey is one of the most complex mixtures of carbohydrates produced by Nature. It is a very important energetic food for its nutritional properties and for its aroma and flavor that depend strongly on the fauna, flowers and on the climatic conditions in the geographic region where the beehive is located. There are no objective, fast and reliable methodologies for the identification of the floral source of honeys. The objective of this work was to develop a methodology to allow identification of the floral source of Brazilian honeys through characterization of its volatile fraction using headspace solid phase microextraction and gas chromatography (HS-SPME-GC). To develop the methodology, 90 samples of Brazilian honeys of twenty different botanical sources and several geographic locations were employed. Eleven honey types had just one sample, allowing only exploratory studies. Different chromatographic profiles were obtained for honeys from different floral sources. Potential chemical markers were identified for the honeys of eucaliptus (Eucalyptus sp), orange (Citrus sp), assa-peixe (Vernonia polianthes), lantana (Lantana montevidensis), morrão of candeia (Croton sp) and quince (Cydonia vulgaris). The results obtained showed that SPME-GC is useful to identify the floral origin of honey and may eventually be used for its certification / Tese (doitorado) - Universidad / Quimica Analitica / Doutor em Ciências

Tendo em vista a importância dos compostos bioativos (CBAs) para a promoção da saúde, foram desenvolvidos, a partir de cruzamentos do tomate cereja com espécies selvagens, os tomates laranja (rico em &#946;-caroteno) e roxo (rico em antocianinas), por meio da técnica de introgressão de alelos. Diante disso, o objetivo deste trabalho foi caracterizar o perfil de compostos bioativos e voláteis dos tomates enriquecidos e avaliar a estabilidade e metabolização de flavonoides do tomate roxo durante digestão in vitro e em modelo animal. Os tomates foram caracterizados quanto ao conteúdo de compostos fenólicos totais; capacidade antioxidante por DPPH e ORAC; ácidos orgânicos; açúcares solúveis; perfil de carotenoides por CLAE/DAD; flavonoides por CLAE/DAD e LC/ESI/MS/MS e compostos voláteis por CG/MS. Avaliou-se ainda a estabilidade dos flavonoides da casca do tomate roxo por simulação da digestão in vitro, utilizando o Simulator of the Human Intestinal Microbial Ecosystem (SHIME), bem como a formação de AGCC por GC-MS, e excreção em ratos Wistar, com posterior identificação dos compostos fenólicos por LC/Q-TOF/MS. O tomate roxo apresentou aumento no conteúdo de fenólicos totais, capacidade antioxidante e vitamina C, com destaque para casca. A rutina foi o principal flavonol identificado em todos os frutos, e na casca do tomate roxo foi encontrado alto teor de petunidina (p-coumaroil)-rutinosídeo-hexosídeo, além da superexpressão de outros flavonoides como a quercetina-3-O-rutinosídeo e kaempferol. Não houve alteração no perfil de flavonoides do fruto laranja. Este, por sua vez, apresentou acúmulo de &#946;-caroteno, importante pró-vitamina A, ao passo que o tomate roxo também teve seus conteúdos de &#946;-caroteno e licopeno aumentados. Os frutos apresentaram perfil de compostos voláteis diferentes entre si, o que foi relacionado à degradação dos diferentes CBAs característicos de cada um. O extrato fenólico da casca de tomate roxo, submetido à digestão in vitro, se manteve estável na primeira porção, relativo às condições estomacais. Contudo, o conteúdo de flavonoides apresentou redução significativa (p<0,05) nas porções que simulam as condições do duodeno e do colón, com a formação de catabólitos pela ação da microbiota intestinal e/ou pela degradação química espontânea. Foi observado o aparecimento de novos ácidos fenólicos não presentes inicialmente na matriz, dentre eles o ácido 3-O-metilgálico e o ácido homovanílico, supostamente derivados da degradação da petunidina e da quercetina, respectivamente. Houve aumento na produção total de AGCC, com excessão do butirato. Na urina dos animais foram detectados diversos outros compostos fenólicos derivados do metabolismo de fase II, dentre eles o ácido hipúrico e o 3-O-metilcatecol. Nas fezes foram identificados cerca de metade dos compostos presentes na fermentação in vitro. Dessa forma, o melhoramento convencional pode ser uma alternativa para o enriquecimento, com CBAs, de alimentos amplamente consumidos pela população, como o tomate. Além disso, durante a passagem pelo trato gastrointestinal, os flavonoides presentes na casca do tomate roxo sofrem intensa degradação pela microbiota intestinal, com formação de catabólitos com reconhecido potencial benefício à saúde. / Considering the importance of bioactive compounds (BACs) for health promotion, the orange (&#946;-carotene-rich) and purple (anthocyanin-rich) tomatoes were developed from cherry tomato interspecific crossing with wild species, using the technique of allele introgression. The objective of this work was to characterize the profile of bioactive and volatile compounds of enriched tomatoes, and to evaluate the stability and metabolism of purple tomato\'s flavonoids during in vitro and in vivo digestion. The tomatoes were characterized by its content of total phenolic compounds; antioxidant capacity (DPPH and ORAC); organic acids; soluble sugars; carotenoids (HPLC/DAD); flavonoids (HPLC/DAD and LC/ESI/MS/MS) and volatile compounds (GC/MS). The stability of the flavonoids from purple tomato peel was assessed by using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), as well as the formation of AGCC by GC-MS, and metabolism and excretion in Wistar rats, with subsequent identification of phenolic compounds by LC/Q-TOF/MS. The purple tomato showed an increase in the total phenolic content, antioxidant capacity and vitamin C, with highlight for the peel. The rutin was the main flavonol identified in all fruits, and it was found high content of petunidin (p-coumaryl)-rutinoside-hexoside in the purple tomato peel, in addition to overexpression of other flavonoids such as quercetin-3-O-rutinoside and kaempferol. There was no change in the flavonoid profile of the orange fruit. This one, in turn, presented accumulation of &#946;-carotene, important pro-vitamin A, while the purple tomato also showed an increase in its &#946;-carotene and lycopene contents. The fruits presented different volatile compounds profile among them, which was related to the degradation of the different BACs composition of each one. In the in vitro digestion, the phenolic extract of the purple tomato peel remained stable in the first portion, relative to the stomach conditions. However, the content of flavonoids presented a significant reduction (p<0.05) in the portions simulating the duodenum and colon, with the formation of catabolites by the action of intestinal microbiota and/or spontaneous chemical degradation. It was observed the appearance of new phenolic acids that was not initially present in the matrix, among them 3-O-methylgalic acid and homovanilic acid, supposedly derived from the degradation of petunidin and quercetin, respectively. There was an increase in the total production of SCFAs, with the exception of butyrate. In the urine of the animals several other phenolic compounds derived from phase II metabolism were detected, among them hippuric acid and 3-O-methylcatechol. About half of the compounds present in the in vitro fermentation were identified in the feces. Conventional breeding may be an alternative for the enrichment, with BACs, of foods that are widely consumed by the population, such as tomatoes. In addition, during the passage through the gastrointestinal tract, the flavonoids present in the purple tomato peel are severely degraded by the intestinal microbiota, with formation of catabolites with recognized potential health benefit.

Les graines de pin (Pinus halepensis Mill., Pinus pinea L., Pinus pinaster et Pinus canariensis) sont les quatre espèces les plus disponibles dans le bassin méditerranéen. Elles sont très utilisées par les populations Nord-africaines en médecine traditionnelle et en gastronomie où elles agrémentent les plats traditionnels (salades, riz, poissons …etc), car elles sont bien connues pour leur excellent goût salé. Cependant, la composition biochimique, les valeurs nutritionnelles, et les mécanismes d'actions cellulaires et moléculaires via lesquels ces graines exercent leurs effets thérapeutiques restent mal élucidés. Le but de notre travail est d'étudier les propriétés physico-chimiques des graines de quatre espèces de pin et la valeur nutritionnelle et pharmaceutique des fractions lipidiques des graines de Pinus halepensis Mill., en utilisant différentes techniques de séparation et d'analyse telles que (DRX, IRTF, CC, LC/MS, GC, GC/MS et RMN) et en examinant la voie principale impliquée dans le développement du cancer qui est l'angiogenèse via des essais biologiques in vitro sur la prolifération et la migration des cellules endothéliales sur Matrigel et in vivo sur une membrane chorioallantoïdienne (CAM) des œufs de poulet ainsi que leurs toxicités sur des cultures cellulaires (Myélome humain HL60, Adénocarcinome du coulon, humain HCT15, Cellules épithéliales A549 et cellules de mélanomes B16F1). Les résultats de la caractérisation physico-chimiques montrent que les quatre graines sont très riches en métabolites primaires (sucres, protéines, protéines de réserve) et secondaires (Phénols totaux et flavonoïdes) comme elles présentent une importante concentration en oligo-éléments (phosphore, potassium, magnésium, Zinc, fer, cuivre et manganèse). Leurs huiles essentielles sont riches en limonène. Les principaux acides gras insaturés pour les quatre espèces sont l'acide linoléique et l'acide oléique. Les propriétés chimiques et physiques de leurs huiles fixes sont dans la norme de qualité agroalimentaire. Les graines de Pinus halepensis Mill. sont les plus riches en lipides totaux qui atteignent un taux de 36% diversifiés chimiquement avec des lipides apolaires (Lipides neutres) et polaires (Quatre classes de glycolipides et six classes de phospholipides). Ces résultats sont de bons indicateurs de la qualité nutritionnelle des graines de pins et impliquent que les lipides neutres, les glycolipides et les phospholipides des graines de Pinus halepensis Mill. dépourvus de toxicité aux concentrations de 1, 10, 25, 50, 100 et 200µg/ml et ayant une activité cytotoxique à 500 et 1000µg/ml et anti-angiogénique in vitro à des concentrations de 100 et 500µg/ml et in vivo à des concentrations de 1mg /ml et 10 mg/ml peuvent être utilisés dans la prévention des maladies liées à l'angiogenèse et à la lutte contre le cancer. / The pine (Pinus halepensis Mill., Pinus pinea L., Pinus pinaster and Pinus canariensis) seeds are the four most available species in the Mediterranean basin. They are widely used by North African populations in traditional medicine and gastronomy where they adorn the traditional dishes (salads, rice, fish ... etc) because they are well known for their excellent taste salty. However, the biochemical composition, nutritional value, and the cellular and molecular mechanisms of action through which these seeds exert their therapeutic effects remain poorly understood. The aim of our study was to investigate the physicochemical properties of pine seed species and nutritional and pharmaceutical value of lipid fractions of Pinus halepensis Mill. Seeds using different separation and analysis techniques such as (XRD, FTIR, CC, LC/MS, GC, GC/MS and NMR) and examining the main pathway involved in the development of cancer which is angiogenesis through biological tests in vitro on the proliferation and migration of endothelial cells on Matrigel and in vivo on a chorioallantoic membrane (CAM) of chicken eggs, thus that their toxicity on healthy cell cultures (human myeloma HL60, Adenocarcinoma of human coulon, HCT15, human epithelial cells, A549 and cells melanoma, B16F1). The results of the physico-chemical characterization showed that four seeds are rich in primary metabolites (sugars, proteins, protein reserves) and secondary (total phenolic and flavonoids) as they have a high concentration of trace elements (phosphorus, potassium, magnesium, zinc, iron, copper and manganese). Their essential oils are rich in limonene. The main unsaturated fatty acids of all species are linoleic acid and oleic acid. The chemical and physical properties of their fixed oils are the in standard food quality. Pinus halepensis Mill. seeds are the richest in total lipids which achieved a rate of 36% chemically diverse with non polar lipids (neutral lipids) and polar lipids (Four classes of glycolipids and six classes of phospholipids). These results are good indicators of the nutritional quality of pine seeds and imply that the neutral lipids, glycolipids and phospholipids of Pinus halepensis Mill. seeds devoid of toxicity at the concentrations of 1, 10, 25, 50, 100 and 200µg/ml and having cytotoxic activity at 500 and 1000µg/ml and anti-angiogenic effect in vitro at the concentrations of 100 and 500 µM and in vivo at the concentrations of 1 mg/ml and 10 mg/ml may be useful in prevention of angiogenesis-related and the fight against cancer diseases.

Contrairement à l’analyse ciblée des composés volatils du vin par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC-MS), les approches par GC-MS non ciblées prennent en compte les composés connus et inconnus. Ces méthodes sont plus rapides et fournissent une représentation plus complète de la composition de l’échantillon. Bien que plusieurs approches non-ciblées aient été développées, il y a encore une forte demande d’outils automatisés pour le traitement des données, en particulier pour les données multidimensionnelles complexes telles que celles de multiples chromatogrammes GC-MS. Ce travail visait à développer deux nouvelles approches chimiométriques pour l’analyse des données GC-MS non ciblées. Ces approches prennent en considération les décalages de temps de rétention entre les échantillons et rendent inutile l’intégration des pics. Elles ont été testées avec un jeu de données GC-MS simulées et un jeu de données GC-MS réelles d’échantillons de vin. De plus, l’une des deux approches GC-MS non ciblée a été combinée à la technique d’analyse sensorielle rapide de "projective mapping". Cette méthodologie a été utilisée pour étudier l’impact de la fermentation malolactique sur des vins issus du cépage Pinotage ainsi que l’effet de l’âge de la vigne, de la turbidité du moût et de la souche de levure sur l’arôme de vins de Riesling expérimentaux. / In contrast to targeted gas chromatography mass spectrometry (GC-MS) analysis of wine volatiles, non-targeted GC-MS approaches take information of known and unknown compounds into account, are faster, inherently more comprehensive and give a more holistic representation of the sample composition. Although several non-targeted approaches have been developed, there is still a great demand for automated data processing tools, especially for complex multi-way data such as chromatographic data obtained from multichannel detectors (e.g. GC-MS chromatograms of multiple samples). This work therefore aimed at the development of data processing procedures for non-targeted GC-MS analysis of volatile wine compounds. The two developed approaches use basic matrix manipulation of segmented GC-MS chromatograms and PCA or PARAFAC multi-way modelling. The approaches take retention time shifts between samples into account and avoid peak integration. A demonstration of the new fingerprinting approaches is presented using an artificial GC-MS data set and an experimental full-scan GC-MS data set obtained for a set of experimental wines. Results of the new approaches were also compared to a references method. Furthermore, the combination of one of the developed GC-MS fingerprinting approaches with the fast sensory screening technique projective mapping was exploited as a powerful approach to simultaneously study the volatile composition and the sensory characteristics of experimental wines. This methodology was used to study the impact of different malolactic fermentation scenarios on two different Pinotage wine styles and for a full factorial investigation of the impact of grape vine age, must turbidity and yeast strain on the aroma of Riesling experimental wines.

The aim of this research was to demonstrate the potential of the novel pre-concentration device, capillary microextraction of volatiles (CMV), for breath analysis. The CMV offers dynamic sampling of volatile organic compounds with its simple coupling to a GC inlet for GC/MS analysis, avoiding expensive thermal desorption instrumentation needed for sorbent tubes, as well as an increased surface area over a single SPME fiber. CMV collectively identified 119 compounds in the breath of 13 self-reported smokers and 7 nonsmokers. The presence and intensity of twelve compounds were used to classify all the nonsmokers 100% of the time using Principal Component Analysis to elucidate the groupings. In some cases, nicotine was not detected in smokers and they were confused with the nonsmokers. Nicotine was detected in the breath of 69% of smokers with an average mass of 143 ± 31 pg for cigarette smokers from the approximate 5 L sample of breath collected. The successful use of the CMV sampler and preconcentration of breath to distinguish between smokers and nonsmokers served as a proof of concept for future applications of the CMV for detection of marijuana smokers’ breath for impaired driver management.

The capillary microextraction of volatiles (CMV) device was equipped with a novel Peltier cooler to investigate cryofocused extraction of organic gunshot residue (OGSR) for the first time. Prior research demonstrated the CMV’s capabilities for detecting nitroglycerin, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite on shooters’ hands via gas chromatography-mass spectrometry. Further method development increased the recoveries of these four target compounds with an optimal 20-minute equilibrium time at 80˚C followed by extracting 3 L at a 1 L/min flow rate. The Cryo-CMV was evaluated for detection of semi-volatile OGSR compounds. The unique challenges presented with sampling of semi-volatiles were overcome by sample heating, applying high (>1 L/min) sampling flow rates and heating the transfer line between the container and cooled CMV. Cryofocusing at -10˚C provided increased recoveries for smokeless powders and OGSR compounds and therefore demonstrates excellent potential for other forensic applications with analysis of VOCs from fire debris and illicit drugs.

A alelopatia, na qual uma espécie causa efeitos negativos sobre outra através da liberação de substâncias químicas, é um fenômeno que pode afetar comunidades vegetais. Em alguns casos, o estabelecimento de arbustos aromáticos em formações densas, com apenas poucas espécies ocorrendo em suas proximidades, é um padrão que tem sido relacionado aos efeitos fitotóxicos dos voláteis que os mesmos liberam. Em campos dos sul do Brasil, esse padrão de estabelecimento frequentemente ocorre para as espécies arbustivas aromáticas Heterothalamus psiadioides Less e Baccharis patens Baker, indicando a possibilidade de alelopatia. Dessa forma, o presente estudo teve como objetivo determinar se H. psiadioides e B. patens são fitotóxicas e se isso implica em efeitos negativos sobre a comunidade vegetal na qual os arbustos ocorrem. Em ensaios em laboratório, os efeitos dos voláteis liberados diretamente das folhas frescas e secas de H. psiadioides e B. patens foram testados sobre a germinação e o crescimento das plantas-alvo alface e cebola nas quatro estações do ano. Em um estudo em campo, foram avaliadas cobertura e biomassa vegetal, número de mudas, diversidade, riqueza, e variáveis de estrutura da vegetação no entorno de ambas as espécies arbustivas e onde não havia arbustos. Nos bioensaios, os voláteis de H. psiadioides e B. patens causaram inibição na porcentagem e velocidade de germinação e redução no tamanho da raiz e da parte aérea das plantas-alvo, sendo que folhas frescas apresentaram maior fitotoxidez. Esses parâmetros foram mais afetados por H. psiadioides que por B. patens em todas as estações, e os efeitos de ambas foram menores no verão. Em relação à investigação em campo, que objetivou avaliar os efeitos da espécie muito fitotóxica H. psiadioides sobre a comunidade vegetal, não foram observadas evidências de alelopatia. Houve maior riqueza e diversidade próximo a H. psiadioides, devido à menor cobertura de gramíneas dominantes. Variáveis de estrutura da vegetação e intensidade de luz explicaram os padrões observados de forma mais conclusiva que alelopatia. Esse estudo sugere que o potencial alelopático de plantas pode ser superestimado em bioensaios e que estudos em campo são necessários para demonstrar se efeitos alelopáticos são realmente relevantes em comunidades vegetais. Ainda, o trabalho ressalta a importância de conduzir estudos mais realistas em laboratório e de utilizar controles em estudos em campo. / Allelopathy, in which a species causes negative effects on another through the release of chemical substances, is a phenomenon that may affect plant communities. In some cases, the establishment of aromatic shrubs in dense stands, with few other species occurring in their surroundings, has been related to the phytotoxic effects of volatiles released by these shrubs. In South Brazilian grasslands, this pattern of establishment often occurs for the aromatic shrub species Heterothalamus psiadioides Less and Baccharis patens Baker, indicating the possibility of allelopathy. Thus, this study aimed to determine if H. psiadioides and B. patens are phytotoxic and if this implicates in negative effects on the plant community in which the shrubs occur. In laboratory assays, the effects of the volatiles released directly from fresh and dry leaves of H. psiadioides and B. patens on germination and growth of the target plants lettuce and onion were evaluated in four seasons. A field study was carried out, in which vegetation cover and biomass, number of seedlings, diversity, richness, and variables of vegetation structure were evaluated in the surroundings of both species and where there were not shrubs. In the bioassays, H. psiadioides and B. patens volatiles inhibited the germination rate and speed of germination and reduced the root and shoot length of the target plants, with fresh leaves showing higher phytotoxicity. These parameters were more strongly affected by H. psiadioides than by B. patens in all seasons, and effects of the both shrubs were lower in summer. In relation to the field investigation that aimed to quantify the effects of the highly phytotoxic H. psiadioides on the plant community, no evidences of allelopathy were found. Richness and diversity were higher near H. psiadioides, due to lower cover of dominant grasses. Variables of vegetation structure and light intensity explained vegetation patterns more conclusively than allelopathy. This study emphasizes that the allelopathic potential of plants can be overestimated in bioassays, and that field studies are necessary to elucidate if allelopathic effects are in fact significant in plant communities. Still, the relevance of conducting more realistic laboratory studies and of using controls in field studies is highlighted.

Sampling and preconcentration techniques play a critical role in headspace analysis in analytical chemistry. My dissertation presents a novel sampling design, capillary microextraction of volatiles (CMV), that improves the preconcentration of volatiles and semivolatiles in a headspace with high throughput, near quantitative analysis, high recovery and unambiguous identification of compounds when coupled to mass spectrometry. The CMV devices use sol-gel polydimethylsiloxane (PDMS) coated microglass fibers as the sampling/preconcentration sorbent when these fibers are stacked into open-ended capillary tubes. The design allows for dynamic headspace sampling by connecting the device to a hand-held vacuum pump. The inexpensive device can be fitted into a thermal desorption probe for thermal desorption of the extracted volatile compounds into a gas chromatography-mass spectrometer (GC-MS). The performance of the CMV devices was compared with two other existing preconcentration techniques, solid phase microextraction (SPME) and planar solid phase microextraction (PSPME). Compared to SPME fibers, the CMV devices have an improved surface area and phase volume of 5000 times and 80 times, respectively. One (1) minute dynamic CMV air sampling resulted in similar performance as a 30 min static extraction using a SPME fiber. The PSPME devices have been fashioned to easily interface with ion mobility spectrometers (IMS) for explosives or drugs detection. The CMV devices are shown to offer dynamic sampling and can now be coupled to COTS GC-MS instruments. Several compound classes representing explosives have been analyzed with minimum breakthrough even after a 60 min. sampling time. The extracted volatile compounds were retained in the CMV devices when preserved in aluminum foils after sampling. Finally, the CMV sampling device were used for several different headspace profiling applications which involved sampling a shipping facility, six illicit drugs, seven military explosives and eighteen different bacteria strains. Successful detection of the target analytes at ng levels of the target signature volatile compounds in these applications suggests that the CMV devices can provide high throughput qualitative and quantitative analysis with high recovery and unambiguous identification of analytes.