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Acceso Abierto Validation of a SPME-GC Method for Azoxystrobin and Pyraclostrobin in Blueberries, and Their Degradation Kinetics(2014) Munitz, Martín S.; Resnik, Silvia Liliana; Montti, María I. T.; Visciglio, SilvioAnalytical method for the residues of strobilurins azoxystrobin and pyraclostrobin in blueberries was developed. Fungicide residues were determined by solid-phase microextraction (SPME) coupled to gas chromatography with micro-electron capture detector. The effect of pH values and fiber coatings were studied. The SPME fiber coating selected was 100 μm PDMS. The method is selective with adequate precision and high accuracy and sensitivity. Recoveries ranged within the 100% - 106% range for azoxystrobin, and 96% - 106% range for pyraclostrobin; and detection and quantification limits were 2.0 and 6.0 μg/kg for azoxystrobin, and 26.0 and 86.0 μg/kg for pyraclostrobin, respectively. Statistical parameters indicated the occurrence of matrix effect; consequently calibration was performed on spiked samples. Degradation of azoxystrobin and pyraclostrobin was studied in blueberry fields located in Concordia, Argentina, with fruits from Emerald and Jewel varieties. The degradation of these fungicides in both blueberry varieties studied followed a first order rate kinetics, and the half-life for azoxystrobin was 11.6 and 17.8 days for Emerald and Jewel cultivars; and for pyraclostrobin was 5.5 and 8.0 days, respectively. - Artículo
Acceso Abierto Amino acid composition of soybean seeds as affected by climatic variables(Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), 2011) Carrera, Constanza Soledad; Reynoso, Cora Marcela; Funes, Gustavo Javier; Martínez, María José; Dardanelli, Julio; Resnik, Silvia LilianaThe objective of this work was to perform a quantitative analysis of the amino acid composition of soybean seeds as affected by climatic variables during seed filling. Amino acids were determined from seed samples taken at harvest in 31 multi‑environment field trials carried out in Argentina. Total amino acids ranged from 31.69 to 49.14%, and total essential and nonessential amino acids varied from 12.83 to 19.02% and from 18.86 to 31.15%, respectively. Variance components expressed as the percentage of total variation showed that the environment was the most important source of variation for all traits, followed by the genotype x environment interaction. Significant explanatory linear regressions were detected for amino acid content regarding: average daily mean air temperature and cumulative solar radiation, during seed filling; precipitation minus potential evapotranspiration, during the whole reproductive period; and the combinations of these climatic variables. Each amino acid behaves differently according to environmental conditions, indicating compensatory effects among them. - Artículo
Acceso Abierto Ocurrencia de alternariol y alternariol monometil éter en jugos de manzana de consumo masivo en la Provincia de Entre Ríos, Argentina(Universidad Nacional de Entre Ríos (UNER), 2014) Broggi, Leticia; Reinoso, Cora; Resnik, Silvia Liliana; Martínez, Fernanda; Drunday, VanesaEl objetivo de este trabajo fue estudiar el índice de contaminación de toxinas de Alternaria, alternariol y alternariol monometil éter en jugos de manzana consumidos en la Provincia de Entre Ríos, Argentina, como así también desarrollar una metodología analítica para la detección y cuantificación de estas toxinas. Se analizaron 37 muestras jugos de manzana, adquiridas en supermercados, almacenes y kioscos de la ciudad de Gualeguaychú, Entre Ríos. La cuantificación se realizó por cromatografía líquida de alta resolución con detector de arreglo de diodos y una columna Thermo BDS Hypersyl. La recuperación para ambas toxinas fue del 89%, los límites de detección fueron 0,62 ng/ml para alternariol y 1,98 ng/ml para monometil éter y los límites de cuantificación fueron 1,0 ng/ml y 3,4 ng/ml respectivamente. No se detectó contaminación por estas toxinas en los jugos analizados. Las metodologías desarrolladas resultaron sensibles y rápidas para cuantificar dichas toxinas en jugos de manzana. - Artículo
Acceso Abierto Occurrence of fungicide residues on Argentinean blueberry fruit and juice samples(Sift Desk, 2016) Munitz, Martín S.; Resnik, Silvia Liliana; Montti, María I. T.; Medina, María B.Azoxystrobin, boscalid, cyprodinil, fludioxonil and pyraclostrobin are fungicides commonly used in Argentina against different fungus contaminations in the blueberry field. The presence of these fungicides was investigated in 50 samples of blueberry fruit and 15 samples of blueberry juice purchased in Argentina. Fungicide residues were determined by solid-phase microextraction (SPME) coupled to gas chromatography with micro-electron capture and nitrogen phosphorous detector. The average concentrations of azoxystrobin were 48 µg/kg in blueberry fruit. Average of boscalid were 43 and 239 µg/kg, of cyprodinil 1581 and 852 µg/kg, of fludioxonil 1077 and 2842 g/kg, and of pyraclostrobin 578 and 3414 µg/kg, in fruits and juice respectively. The higher concentrations of fungicides were found in those cases where the time between the application of the compound and the fruit’s commercialization was shorter than the fungicide’s half-life.