Comparison between extraction methods to obtain volátiles from lulo (Solatium quitoense) pulp / Comparación entre métodos de extracción para la obtención de volátiles a partir de pulpa de lulo (Solanum qu toense) / Comparação entre métodos de extração para a obtenção de voláteis a partir da polpa de lulo (Solanum quitoense)

Simultaneous Distillation-Solvent Extraction (SDE) and Headspace Solid Phase Micro-extraction (HS-SPME), coupled to Gas Chromatography-Mass Spectrometry (GC-MS), for recovery of volatiles from lulo pulp (Solanum quitoense) were compared. A completely randomized SDE/GC-MS design was applied to establish differences between the areas obtained with different solvents, whereas a two-way HS-SPME/GC-MS indicated the most appropriate extraction conditions of volatiles, having the type of fiber and the adsorption temperature as factors. SDE/GC-MS mainly promoted the extraction of hydrocarbons, aldehydes, and esters; whereas esters and aldehydes had higher areas using HS-SPME/GC-MS. Furthermore, the variance analysis showed a significant interaction among the type of fiber, the adsorption temperature, and the functional groups.

Se compararon los métodos de extracción y destilación simultánea (SDE) y microextracción en fase sólida con espacio de cabeza (HS-SPME), acoplados a cromatografía de gases con detector de espectrometría de masas (GC-MS), para la recuperación de volátiles a partir de pulpa de lulo (Solanum quitoense). Se realizó un diseño completamente al azar aplicado al tipo de solvente para SDE/GC-MS, mientras que para HS-SPME/GC-MS se ejecutó un diseño a dos vías, teniendo como factores el tipo de fibra y la temperatura de adsorción. En el primer caso se obtuvieron principalmente hidrocarburos, aldehídos y ésteres; en el segundo, se recuperaron ésteres y aldehídos. El análisis de varianza mostró una interacción significativa entre el tipo de fibra, la temperatura de adsorción y los grupos funcionales.

Foram comparados os métodos de extração e destilação simultânea (SDE) e microextração em fase sólida com espaço de cabeça (HS-SPME), acopladas à cromatografia gasosa-espectrometria de massa (GC-MS), para à recuperação de voláteis a partir da polpa de lulo (Solanum quitoense). Foi realizado um delineamento completamente casualizado aplicado ao tipo de solvente para à SDE/GC-MS, enquanto à HS-SPME/GC-MS foi executado um desenho de duas vias, tendo como fatores o tipo de fibra e a temperatura de adsorção. No primeiro caso foram obtidos sobretudo hidrocarbonetos, aldeídos e ésteres; no segundo foram obtidos ésteres e aldeídos. A análise de variância mostrou uma interação significativa entre o tipo de fibra, a temperatura de adsorção e os grupos funcionais.

Metabolomics and pesticides: systematic literature review using graph theory for analysis of references / Metabolómica y Pesticidas: Revisión sistemática de literatura usando teoría de grafos para el análisis de referencias

The systematic literature review presented here is designed to illustrate the role of metabonomics and metabolomics in pesticide exposure studies. The search was conducted in Thomson Reuters Web of Science (ISI Web of Knowledge) database. The references and citations for each article were downloaded for analysis. Graph theory was used to determine relevant articles and distinct relationships between classic and current research in this field through its structural characteristics. The initial network included 4423 nodes and 4978 links, from which indegree, outdegree and betweenness indicators were extracted. After preprocessing the data, the network was reduced to 415 nodes and 974 links. From this network, 80 articles with the highest score between the three indicators were extracted for review. This methodology allowed for the identification of different perspectives of metabolomic and metabonomic pesticide studies that included the mode and mechanism of action, toxicological and biological monitoring, environmental metab-olomics, metabolism, dose response and biomarkers and its role in pesticide exposure.

La revisión sistemática de literatura presentada a continuación tiene como objetivo dar a conocer el rol que han tenido la metabolómica en el estudio de la exposición a plaguicidas. La búsqueda se llevó a cabo en la base de datos Thomson Reuters Web of Science (ISI Web of Knowledge). Posteriormente, se descargaron todos los registros producto de resultado de la búsqueda y cada citación dentro de cada artículo. Estas referencias fueron analizadas mediante la teoría de grafos con el fin de identificar los artículos más relevantes, los artículos clásicos y recientes y los que presentan mayor intermediación en el tema de investigación. La red de citaciones fue construida con inicialmente con 4423 nodos (artículos) y 4978 enlaces (citaciones) a los cuales se les determinó los indicadores de grado de entrada, grado de salida y centralidad en el grafo. Posteriormente, esta red de citaciones fue procesada eliminando los artículos desconectados, reduciendo la red a 415 nodos y 974 enlaces. De esta red ya procesada se extrajeron 80 artículos que presentaron mayores indicadores de grado y centralidad. Finalmente, esta metodología permitió la identificación de diferentes perspectivas de los estudios metabolómicos y metabonómicos en la exposición a plaguicidas que incluyen estudios de modo de acción, mecanismos de acción, monitoreo biológico y toxicológico, metabolómica ambiental, metabolismo, dosis respuesta e identificación de biomarcadores.

Hollow-fiber solvent bar microextraction with gas chromatography and electron capture detection determination of disinfection byproducts in water samples.

A liquid-phase microextraction method that uses a hollow-fiber solvent bar microextraction technique was developed by combining gas chromatography with electron capture detection for the analysis of four trihalomethanes (chloroform, dichlorobromomethane, chlorodibromomethane, and bromoform) in drinking water. In the microextraction process, 1-octanol was used as the solvent. The technique operates in a two-phase mode with a 5 min extraction time, a 700 rpm stirring speed, a 30°C extraction temperature, and NaCl concentration of 20%. After microextraction, one edge of the membrane was cut, and 1 µL of solvent was collected from the membrane using a 10 µL syringe. The solvent sample was directly injected into the gas chromatograph. The analytical characteristics of the developed method were as follows: detection limits, 0.017-0.037 ng mL-1 ; linear working range, 10-900 ng mL-1 ; recovery, 74 ± 9-91 ± 2; relative standard deviation, 5.7-10.3; and enrichment factor, 330-455. A simple, fast, economic, selective, and efficient method with big possibilities for automation was developed with a potential use to apply with other matrices and analytes.

Ultrasonic degradation of acetaminophen in water: effect of sonochemical parameters and water matrix.

This paper deals about the sonochemical water treatment of acetaminophen (ACP, N-acetyl-p-aminophenol or paracetamol), one of the most popular pharmaceutical compounds found in natural and drinking waters. Effect of ultrasonic power (20-60 W), initial ACP concentration (33-1323 µmol L(-1)) and pH (3-12) were evaluated. High ultrasonic powers and, low and natural acidic pH values favored the efficiency of the treatment. Effect of initial substrate concentration showed that the Langmuir-type kinetic model fit well the ACP sonochemical degradation. The influence of organic compounds in the water matrix, at concentrations 10-fold higher than ACP, was also evaluated. The results indicated that only organic compounds having a higher value of the Henry's law constant than the substrate decrease the efficiency of the treatment. On the other hand, ACP degradation in mineral natural water showed to be strongly dependent of the initial substrate concentration. A positive matrix effect was observed at low ACP concentrations (1.65 µmol L(-1)), which was attributed to the presence of bicarbonate ion in solution. However, at relative high ACP concentrations a detrimental effect of matrix components was noticed. Finally, the results indicated that ultrasonic action is able to transform ACP in aliphatic organic compounds that could be subsequently eliminated in a biological system.

Determinación de niveles residuales de tetraciclina en canales bovinas por la técnica de ELISA en el frigorífico Friogan (La Dorada) / Determination of residual tetracycline levels in bovine carcasses by means of ELISA in the Friogan slaughterhouse (La Dorada, Caldas, Colombia)

En las políticas sanitarias colombianas se estableció la importancia del control de residuos de medicamentos veterinarios, considerando la preocupación mundial por sus implicaciones en salud pública. El trabajo buscó detectar y cuantificar las concentraciones de residuos de tetraciclinas en músculo de 114 animales sacrificados en FRIOGAN (La Dorada, Caldas) por ELISA, siendo referencia los LMR de la Unión Europea (100 ppb) y del Codex Alimentarius (200 ppb). El 61,5% de las muestras presentaron concentraciones superiores a 100 ppb y el 23,7% a 200 ppb. Los resultados sugieren que fallan las Buenas Prácticas en la Administración de Medicamentos en la producción primaria y que existen falencias en la inocuidad cárnica.

The Colombian sanitary policies have established the importance in the control of veterinary medicines residues, considering the world-wide concern due to its public health implications. The objective of this research was to detect and to quantify, by means of ELISA, the tetracycline residue concentrations in the muscle of 114 slaughtered animals at the Friogan slaughterhouse (La Dorada-Caldas), using the MRL of the European Union (100 ppb) and the Codex Alimentarius (200 ppb) as reference. The results showed that 61.5% of the samples presented concentrations above 100 ppb and 23.7% above 200 ppb. These results suggest that the Good Practices of Medicine Administration are failing, and that there are errors in meat innocuousness.

Composition of the water-soluble fraction of different cheeses.

Volatile and nonvolatile compounds present in the water-soluble fraction (WSF) and water-soluble fraction with molecular weight lower than 1000 Da (WSF < 1000 Da) of six Spanish cheeses, Cabrales, Idiazábal, Mahón, Manchego, Roncal, and a goat's milk cheese, were analyzed. Different nitrogen fractions (determined by Kjeldahl method), caseins (by capillary electrophoresis), peptides and amino acids (by HPLC), and volatile components (by dynamic headspace coupled to GC-MS) as well as mineral content in the cheese fractions were analyzed and compared. The different nitrogen and volatile compounds identified in the WSF were characteristic of each cheese variety. Cabrales cheese displayed the highest content of free amino acids and the highest quantity and variety of volatile compounds. The WSF < 1000 Da fraction was less representative, especially for volatile compounds, as some of the components were lost in the ultrafiltration. Alcohols were better recovered than ketones and esters.