Quantification of chrysene and benzo(a)pyrene in surface water samples by fluorescence measurement / Quantificação de cristão e benzo (a) pireno em amostras de água de superfície por medição de fluorescência

Polycyclic aromatic hydrocarbons, or PAHs, are compounds of organic nature derived from burning other organic compounds. They are common in nature, but in high concentrations are a sign of pollution and have harmful effects on human health. Therefore, techniques to identify and quantify these compounds in environmental samples, especially water samples, become essential. In this paper we apply the technique of synchronous fluorescence spectroscopy to identify and quantify types of PAH in water samples, showing the simplicity of execution and low cost of the technique over other ones conventionally used and reported. For this study, we choose two PAH which seem to be the most common in the environment and are associated with several diseases, including cancer. Analytical curves were constructed, and analytical parameters for their determination collected; limits of detection and quantification were 2.0 and 6.7 ng.mL-1 for chrysene and 1.7 and 5.7 ng.mL-1 for benzo[a]pyrene, respectively. To study the validity of the proposed method, water samples collected from a stream in the city of Dourados (MS, Brazil) were studied. At each of the collection points, significant concentrations of chrysene and benzo[a]pyrene was detected, mostly at levels above those permitted by international regulatory organizations

A Espectroscopia de Fluorescência Sincronizada Aplicada na Análise Qualitativa e Quantitativa de Hidrocarbonetos Policíclicos Aromáticos em Amostras D’água

Os Hidrocarbonetos Policíclicos Aromáticos (HPAs) são conhecidos por serem altamente tóxicos. Diferentes métodos são utilizados para identificação destes compostos em amostras ambientais, entretanto, quase sempre, envolvem alta complexidade para as análises e custos significativamente altos. Contudo a técnica de Espectroscopia de Fluorescência Sincronizada (EFS) se mostra altamente simples e eficaz no processo de identificação destas substâncias. Neste contexto, o trabalho objetivou realizar um estudo quali-quantitativo de HPAs presentes em matrizes aquosas no intuito de propor a técnica de EFS como uma ferramenta para o monitoramento ambiental. Após as análises estatísticas verificou-se que o limite de detecção foi abaixo de 0,7x10-9 g.mL-1 para os oito HPAs identificados pela técnica de EFS, valor este recomendado pelo Ministério da Saúde no Brasil, demonstrando que a técnica é altamente sensível e aplicável a rotina de analises em amostras de água

Application of Optical Fluorescence Spectroscopy for Studying Bee Abundance in Tropaeolum majus L. (Tropaeolaceae)

Tropaeolum majus L. species produce flowers with all sorts of colors, from yellow to red. This work aimed to apply optical fluorescence spectroscopy to study bee abundance in T. majus, answering the following questions: (1) do corolla temperature and weather conditions affect the abundance of visiting bee species? (2) do flower color and corolla fluorescence affect the abundance of visiting bee species? (3) do red flowers attract more visiting bees? (4) is there a relationship between bee visits and flower compounds? The bee species Apis mellifera, Paratrigona lineata, and Trigona spinipes were the most observed in T. majus flowers. The latter was more active in the morning and preferred orange and yellow flowers. These colors also had higher temperatures and fluorescence emissions than did the red ones and those with yellow-red and orange-red nectar guides. Orange flowers emitted a broadband UV spectrum (between 475 and 800 nm). This range might be due to compounds such as hydroxycinnamic acid, flavonols, isoflavonoids, flavones, phenolic acid, and chlorophyll. Extracts from different T. majus corolla colors showed that flowers emit specific fluorescent signals, mainly related to bee color vision and learning, thus acting as a means of communication between bees and flowers. In this way, this information evidences the interaction between bees and T. majus flowers, allowing conservation actions for pollinators