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Li J.,KTH Royal Institute of Technology | Martin-Sampedro R.,National Institute for Agriculture and Food Research and Technology | Pedrazzi C.,Federal University of Vicosa | Gellerstedt G.,KTH Royal Institute of Technology
Holzforschung | Year: 2011

The effect of milling time on the structure of lignin was investigated by analyzing the quantity and molecular size distribution of thioacidolysis products obtained from wood and pulp of eucalypt (Eucalyptus globulus). After milling, the ability of three solvent systems was determined to completely dissolve the wood or pulp meal. It was found that a mixture of DMSO and 50% aqueous tetrabutylammonium hydroxide was superior to either dimethylacetamide- LiCl or DMSO-tetrabutylammonium fluoride as solvent. By applying the minimum milling time required for complete dissolution, structurally unaltered wood or pulp could be further separated into lignin-carbohydrate fractions. These were analyzed by thioacidolysis. From eucalypt pulp, two different lignin-carbohydrate fractions were obtained, one glucan- and one xylan-enriched fraction, with the latter having more syringyl units in its lignin moieties. The developed solvent system seems to be universal because spruce and flax fibers and pulps could also be dissolved in it after milling. © 2011 by Walter de Gruyter Berlin New York. Source

Ucles Moreno A.,University of Almeria | Herrera Lopez S.,University of Almeria | Reichert B.,Federal University of Santa Maria | Lozano Fernandez A.,University of Almeria | And 2 more authors.
Analytical Chemistry | Year: 2015

This manuscript reports a new pesticide residue analysis method employing a microflow-liquid chromatography system coupled to a triple quadrupole mass spectrometer (microflow-LC-ESI-QqQ-MS). This uses an electrospray ionization source with a narrow tip emitter to generate smaller droplets. A validation study was undertaken to establish performance characteristics for this new approach on 90 pesticide residues, including their degradation products, in three commodities (tomato, pepper, and orange). The significant benefits of the microflow-LC-MS/MS-based method were a high sensitivity gain and a notable reduction in matrix effects delivered by a dilution of the sample (up to 30-fold); this is as a result of competition reduction between the matrix compounds and analytes for charge during ionization. Overall robustness and a capability to withstand long analytical runs using the microflow-LC-MS system have been demonstrated (for 100 consecutive injections without any maintenance being required). Quality controls based on the results of internal standards added at the samples' extraction, dilution, and injection steps were also satisfactory. The LOQ values were mostly 5 μg kg-1 for almost all pesticide residues. Other benefits were a substantial reduction in solvent usage and waste disposal as well as a decrease in the run-time. The method was successfully applied in the routine analysis of 50 fruit and vegetable samples labeled as organically produced. © 2014 American Chemical Society. Source

Karoui S.,National Institute for Agriculture and Food Research and Technology | Diaz C.,National Institute for Agriculture and Food Research and Technology | Serrano M.,National Institute for Agriculture and Food Research and Technology | Cue R.,National Institute for Agriculture and Food Research and Technology | And 2 more authors.
Animal Reproduction Science | Year: 2011

The fact that results of artificial insemination (AI) are declining in highly selected dairy cattle populations has added a renewed interest to the evaluation of male fertility. Data from 42,348 ejaculates collected from 1990 to 2007 on 502 Holstein bulls were analysed in a Bayesian framework to provide estimates of the evolution of semen traits routinely collected in AI centres throughout the last decades of intense selection for production traits and estimate genetic parameters. The traits under consideration were volume (VOL), concentration (CONC), number of spermatozoa per ejaculate (NESPZ), mass motility score (MM), individual motility (IM), and post-thawing motility (PTM). The environmental factors studied were year-season and week of collection, which account for changes in environmental and technical conditions along time, age at collection, ejaculate order, time from previous collection (TPC) and time between collection and freezing (TCF) (only for PTM). Bull's inbreeding coefficient (Fi), bull's permanent environmental and additive genetic effects were also considered. The use of reduced models was evaluated using the Bayes factor. For all the systematic effects tested, strong or very strong evidence in favour of including the effect in the model was obtained, except for Fi for motility traits and TCF for PTM. No systematic time trends for environment or bull effects were observed, except for PTM, which showed an increasing environmental trend, associated with improvements in freezing-thawing protocols. Heritability estimates were moderate (0.16-0.22), except for IM, which presented a low value (0.07). Genetic correlations among motilities and between motilities and CONC were large and positive [0.38-0.87], VOL showed a negative correlation with CONC (-0.13) but with ample HPD95%. The magnitude of heritabilities would allow an efficient selection if required and grants the use of these traits as indicators of the sperm viability component of bulls breeding soundness. © 2011 Elsevier B.V. Source

Ucles A.,University of Almeria | Herrera Lopez S.,University of Almeria | Dolores Hernando M.,National Institute for Agriculture and Food Research and Technology | Rosal R.,University of Alcala | And 2 more authors.
Talanta | Year: 2015

The use of yttria-stabilized zirconium dioxide nanoparticles as d-SPE clean-up sorbent for a rapid and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the determination of post-harvest fungicides (carbaryl, carbendazim, chlorpropham, diphenylamine, ethoxyquin, flutriafol, imazalil, iprodione, methomyl, myclobutanil, pirimiphos-methyl, prochloraz, pyrimethanil, thiabendazole, thiophanate-methyl and tolclofos-methyl) in orange and pear samples has been evaluated and validated. The sample preparation was a modification of the QuEChERS extraction method using yttria-stabilized zirconium dioxide and multi-walled carbon nanotubes (MWCNTs) nanoparticles as the solid phase extraction (d-SPE) clean-up sorbents prior to injecting the ten-fold diluted extracts into the LC system. By using the yttria-stabilized zirconium dioxide extraction method, more recoveries in the 70-120% range were obtained - thus this method was used for the validation. Quantification was carried out using a matrix-matched calibration curve which was linear in the 1-500 μg kg-1 range for almost all the pesticides studied. The validated limit of quantification was 10 μg kg-1 for most of the studied compounds, except chlorpropham, ethoxyquin and thiophanate-methyl. Pesticide recoveries at the 10 and 100 μg kg-1 concentration levels were satisfactory, with values between 77% and 120% and relative standard deviations (RSD) lower than 10% (n=5). The developed method was applied for the determination of selected fungicides in 20 real orange and pear samples. Four different pesticide residues were detected in 10 of these commodities; 20% of the samples contained pesticide residues at a quantifiable level (equal to or above the LOQs) for at least one pesticide residue. The most frequently-detected pesticide residues were: carbendazim, thiabendazole and imazalil-all were below the MRL. The highest concentration found was imazalil at 1175 μg kg-1 in a pear sample. © 2015 Elsevier B.V. All rights reserved. Source

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