Essential oils are volatile compounds commonly used by several industries, easily degradable, which restrains their applications. Therefore, we developed and validated a methodology for producing microcapsules loaded with orange essential oil, using a spray-drying process. The experimental design results showed that the combination between a low flow transfer rate (0.15 L h −1 ) of the colloidal suspension, a higher drying air flow rate (536 L h −1 ), and an inlet air temperature of 150 °C to the spray-dryer were the most important parameters for the atomization efficiency. The method optimization resulted in microcapsules with powder recovery between 7.6 and 79.9% (w w −1 ), oil content ranging from 8.9 to 90.4% (w w −1 ), encapsulation efficiency between 5.7 and 97.0% (w w −1 ), and particle sizes with a high frequency of distribution less than 4 μm. In these experiments, gelatin and lignin were evaluated as biopolymers of encapsulation. We also developed an analytical method using headspace gas chromatography. The matrix effects could be addressed by using matrix-matched calibration curves. The chromatographic analysis was linear and selective for d -limonene between 0.025 and 3.00 µg mL −1 , with correlation coefficients higher than 0.99. The analytical method had limits of detection and quantitation of 0.024 and 0.073 mg g −1 for gelatin and 0.039 and 0.119 mg g −1 for lignin, respectively.

No abstract

Recebido em 22/1/12; aceito em 6/7/12; publicado na web em 31/8/12 ANALYSIS OF PESTICIDES IN WATER USING LIQUID-LIQUID EXTRACTION WITH PARTITION AT LOW TEMPERATURE AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. This study optimized and validated the liquid-liquid extraction technique with partition at low temperature (LLE-PLT) for identification and quantification of four pesticides (chlorpyrifos, λ-cyhalothrin, permethrin, bifenthrin) in water samples. Analyses were performed by HPLC-UV. The technique was efficient for pesticide recovery with extraction exceeding 86%. Chromatographic response was linear for the four compounds in the 10-45 µg L -1 range, with correlation coefficients greater than 0.99. Limits of detection and quantitation were less than 3.5 µg L -1 and equal to 10 µg L -1 , respectively. The proposed method was applied to 29 water samples from the Jaíba Project in northern Minas Gerais.Keywords: LLE-LTP; pesticides; HPLC-UV. INTRODUÇÃOO Projeto Jaíba é um amplo projeto de irrigação de grande importância para todo o Norte de Minas.1 A água utilizada para irrigação é coletada em canais próximos às próprias plantações (Figura 1S, material suplementar), apresentando elevado risco de contaminação devido a sua localização geográfica, fenômenos de lixiviação 2,3 e aplicações de agrotóxicos por via aérea. 4 Os agrotóxicos são largamente empregados para minimizar perdas na produtividade, atribuídas ao ataque de pragas. 5,6 A aplicação de agrotóxicos pode gerar resíduos no ar, solo e na água, expondo indiretamente o ser humano.7 Por isso, as agências reguladoras estabelecem limites máximos de resíduo permitido (LMR) em diversas matrizes. 8,9 Esses valores de LMR são estabelecidos levando em consideração vários fatores, dentre eles a toxicidade do composto para seres humanos e o limite de quantificação dos métodos instrumentais de análises. Devido à exigência da legislação e à toxicidade destas substâncias, o consumo desta água ou sua reutilização na agricultura pode resultar em riscos à saúde pública.A região do Projeto Jaíba se destacou nos últimos anos na produção de banana prata, limão tahiti e manga.10 Nestas culturas, clorpirifós, λ-cialotrina, permetrina e bifentrina representam agrotóxicos comuns para o controle de pragas.9 Embora destes quatro agrotóxicos apenas a permetrina seja regulamentada pela Portaria 518 de 2004 em amostras de água, 11 o uso constante dessas substâncias torna a análise e o monitoramento fundamentais para preservar a saúde humana e o meio ambiente.O primeiro passo para análise e monitoramento destas substâncias em água envolve o desenvolvimento da técnica de extração. Esta etapa visa remover seletivamente resíduos de agrotóxicos destas amostras e pré-concentrá-los. 12 As principais técnicas existentes são a extração em fase sólida, 13-15 microextração em fase sólida, 16-19 microextração líquido-líquido 20-23 e microextração em gota única. 24Apesar do elevado número de técnicas existentes, a extração líquido-líquido com partição em baixa temperatura (ELL-PBT) tem se apresentado...

No abstract

Soybean crop is regulated by abiotic and biotic stresses with great potential in reducing grain yield and quality. The selection of resistant cultivars is a promising approach for mitigating these damages. We evaluated the chemical profile of Glycine max leaves from different cultivars in order to explore their defense mechanisms against Spodoptera cosmioides caterpillars. We optimized solid–liquid extraction techniques using ultrasound bath and static headspace extraction. Additionally, we developed an approach based on liquid and gas chromatography for analyzing the chemical profile of G. max cultivars. The principal component analysis allowed the classification of transgenic cultivars, which are classified as susceptible to S. cosmioides, from those obtained by genetic improvement and resistant to the insect. Differences were observed in the abundance of phenolic glycosides, lipids, aldehydes, and alcohols. More specifically, S. cosmioides resistant cultivars presented molecules related to the jasmonic and salicylic acid pathways. Such data can contribute to a molecular understanding of phenotypic diversity in soybean cultivars, from plant quality to resistance mechanisms and adaptation, to environmental stress and herbivory.