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The demand for agar, thanks to its different uses, generates the need to look for alternative substances that replace it. This work studied the influence of four different additions of potato starch into agar media (T1 = 50%, T2 = 45%, T3 = 40% and T4 = 0%) on the growth and chemical composition of essential oils of lulo (Solanum quitoense) explants cultured in vitro. The lengths, fresh and dry biomass weights, and number of nodes of the lulo explants were selected as growth indices and compared against either viscosity of the modified media or extraction percentage and relative concentration of the main components in the essential oils. A higher statistic variability and amount, of the lengths, fresh biomass and number of nodes, were found for the explants cultured in modified agar media compared to those cultured in pure agar. In contrast, minimal variation in metabolite extractions and concentrations were obtained as a function of potato starch addition. Cyclotetradecane, neophytadiene, 1-hexadecene, phytol, oleamide and 3-octadecene were found as the main components of the essential oils by gas chromatography-mass spectrometry (GC-MS). It was found that T1 was the treatment that yielded the best results in the analyzed variables. Key words: Solanum tuberosum starch, in vitro culture, micropropagation, partial substitution, Solanum quitoense in vitro essential oil, secondary metabolites.

International audience; In atmospheric chemistry, each aerosol particle acts as a small mobile reactor where several heterogeneous chemical reactions lead to the modification of its size, chemical composition and structure; as well as the consumption and release of chemical agents from its gaseous environment. Despite its relevance, information on the chemical and photochemical processes that occur in atmospheric aerosols is still scarce, mainly due to the instrumental difficulties involved in studying such processes on a surface scale. In this regard, Micro-Raman spectroscopy coupled to a levitation technique, through an environmental levitation cell, is especially useful for studying - at micrometric scale - the in-situ modifications of aerosol when exposed to reactive or damp environments without the influence of a contacting surface (Krieger, et al. 2012). This work deals with two main objectives. On one hand, the monitoring of physical- and photo-chemical processes occurring in levitated single particles; and in the other hand, the coupling and instrumental developments carried out to perform Raman imaging studies of single levitated particles. We will show the coupling between the confocal Raman microscope and the adapted photochemical environmental levitation cell, as well as the heterogeneous distribution of (photo)chemical products on levitated particles (less than 10 µm of size) evidenced by reconstruction of the Raman spectral image.This work was supported by funds from the “Laboratoire d’Excellence” (LABEX) -CaPPA- (ANR-11-LABX-0005-01) and CPER research project CLIMIBIO.Andreae, M. O., and Crutzen, P. J. (1997). Science 276, 1052-1058. Krieger, U. K., Marcolli, C., and Reid, J. P. (2012). Chem. Soc. Rev. 41, 6631-6662.

International audience

This work evaluates the efficiency in the extraction of the cyanogenic glycoside amygdalin [D-mandelonitrile- p-D-gentiobioside] from seeds of apples (Malus pumila Mill) by using the two most conventional solid-to-liquid methodologies (reflux and Soxhlet) in relation to the more contemporary microwave technique. The extraction efficiencies are determined by an optimized and standardized high-performance liquid chromatography (HPLC) method that requires retention times of about 1 min only. The best chromatographic separation of amygdalin is found in extracts obtained using the reflux method; however, the highest total separation efficiency, requiring only 10% of total time and the solvents inverted in reflux or Soxhlet extraction, is reached by employing microwave radiation. In contrast, the higher extraction amounts of amygdalin from the seeds are obtained using the Soxhlet solid-to-liquid technique. With the Soxhlet methodology, quantities of amygdalin from apple seeds are obtained in excess of three times and twice those obtained with reflux and microwave methodologies, respectively. The purity and structural identification of the extracted amygdalin were verified spectroscopically using UV-vis, NMR and FTIR techniques. Resumen En este trabajo se evalúa la eficiencia en la extracción del glucósido cianogénico amigdalina de semillas de manzanas (Maluspumila Mill) empleando las técnicas tradicionales con solventes de reflujo y Soxleth, las cuales son comparadas con la técnica más contemporánea de microondas. Las eficiencias de extracción son determinadas a través de cromatografía líquida de alta eficiencia (HPLC) empleando un método estandarizado que requiere tiempos de retención de alrededor de 1 minuto. La mejor separación cromatográfica es obtenida con el método de reflujo; sin embargo, la eficiencia de separación total más alta es alcanzada empleando la técnica de microondas, la cual requiere de solo un 10% del tiempo total y solventes necesarios en las extracciones por reflujo y Soxhlet. En contraste, la mayor cantidad de extraída de amigdalina de las semillas es obtenida con la técnica de Soxhlet, la cual corresponde al triple y al doble de las cantidades que logran ser extraídas con las metodologías de reflujo y microondas respectivamente. La pureza e identificación estructural de la amigdalina extraída es verificada espectroscópicamente usando las técnicas de UV-vis, RMN (*H and 13C) y FTIR.

By oxidation of selenoacetic acid, CH3C(O)SeH, we have prepared the hitherto unknown diacetyl diselenide, [CH3C(O)Se]2. Its vibrational properties were studied experimentally, both in neat liquid (Fourier transform infrared spectroscopy and Raman) with the molecule isolated in argon matrix at low temperatures and theoretically using MP2 and B3LYP methods in combination with 6-31+G(d), 6-311++G(3df,3dp) or aug-cc-pvDZ basis sets. Analysis of Ar matrix spectra reveals a conformational equilibrium in gas phase at room temperature, which was interpreted by considering only two of the three stable rotamers predicted by our three-dimensional potential energy surface scans. Energetic properties of three minima found theoretically were further studied in terms of donor?acceptor interactions by using natural bond orbital calculations at the same levels of theory. From this, it was possible to rationalize the conformational stability order and molecular structures by means of vicinal hyperconjugative delocalizations involving lone pairs on selenium or oxygen atoms and C=O, C?C or Se?C antibonding orbitals. The photochemistry of the compound in the argon matrix in the range between 200 and 800 nm was also investigated, revealing only one photochemical path to produce ketene, H2C=C=O, methylselane, CH3SeH, and carbonyl selenide, OCSe. Copyright © 2016 John Wiley & Sons, Ltd. Fil: Gómez Castaño, Jovanny Arles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina. Universidad Pedagógica y Tecnológica de Colombia; Colombia Fil: Romano, Rosana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina Fil: Salamanca, Ana R.. Universidad Pedagógica y Tecnológica de Colombia; Colombia Fil: Amésquita, Germán. Universidad Pedagógica y Tecnológica de Colombia; Colombia Fil: Beckers, Helmut. Bergische Universität Wuppertal; Alemania Fil: Willner, Helge. Bergische Universität Wuppertal; Alemania Fil: Della Védova, Carlos Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina

Uno de los factores de mayor importancia relacionados con la condición del medio ambiente es la calidad del agua y por lo tanto, el conocimiento del grado de pureza que esta presenta. Para determinar dicha calidad se utiliza la medición de varios parámetros, los cuales se pueden clasificar generalmente en biológicos, químicos y fisicoquímicos; así el conocimiento acerca del contenido de metales pesados y de parámetros fisicoquímicos tales como O.D (Oxigeno Disuelto), D.B.O. (Demanda Biológica de Oxigeno), D.Q.O. (Demanda Química de Oxigeno), Turbidez, pH son importantes para estimar la posible contaminación natural, industrial y/o agroindustrial de la fuente de agua., Pregrado, Químico