Sulfur precursor and citric acid effect on SnS nanoparticles and their influence on the photodegradation activity of selected organic compounds.

Semiconductor nanoparticle-mediated photocatalysis is an attractive option for water decontamination, being the semiconductors as SnS with a bandgap in the visible region, the most promising materials. In the present work, we evaluated the influence of important parameters in the photocatalytic application of SnS nanoparticles. Our results show that the presence of citric acid (used as a capping agent) restricts the formation of hexagonal nanoparticles.

Determination of multiclass, semi-polar pesticide residues in fatty fish muscle tissue by gas and liquid chromatography mass spectrometry.

With the aim of monitoring multiclass semi-polar pesticide residues in freshwater fatty fish, two QuEChERS approaches (so-called acetate buffered and unbuffered versions) were evaluated for the determination of 77 pesticide residues. Compounds were selected according to the dominant rainfed agriculture activities in South America. Unbuffered QuEChERS was finally chosen for validation purposes owing that it provided the best results in terms of recovery yields.

Isolation and Structural Characterization of Bioactive Molecules on Prostate Cancer from Mayan Traditional Medicinal Plants.

Prostate cancer is the most common cancer in men around the world. It is a complex and heterogeneous disease in which androgens and their receptors play a crucial role in the progression and development. The current treatment for prostate cancer is a combination of surgery, hormone therapy, radiation and chemotherapy.

Occurrence of pesticide residues in fish from south American rainfed agroecosystems.

Environmental sustainability of South American rainfed agroecosystems is of current concern. In this work, we evaluate the occurrence of multiple pesticide residues in muscle tissue of wild fish species from two large rivers in South America (Uruguay and Negro Rivers). Two sampling campaigns (representing summer and winter crops) were performed during 2015 targeting a wide biodiversity of fish species used for human consumption (ranging from migratory to non-migratory and from detritivorous to top-predators).

Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing.

The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS.

Detection of pesticides in active and depopulated beehives in Uruguay.

The influence of insecticides commonly used for agricultural purposes on beehive depopulation in Uruguay was investigated. Honeycombs, bees, honey and propolis from depopulated hives were analyzed for pesticide residues, whereas from active beehives only honey and propolis were evaluated. A total of 37 samples were analyzed, representing 14,800 beehives.

Determination of coumaphos, chlorpyrifos and ethion residues in propolis tinctures by matrix solid-phase dispersion and gas chromatography coupled to flame photometric and mass spectrometric detection.

A new analytical method has been developed and successfully evaluated in routine application for the quantitative analysis of a selected group of organophosphate pesticides (coumaphos, chlorpyrifos and ethion) which can be found at trace levels in propolis tinctures (ethanolic propolis extracts); a valuable commodity used as raw material in the food and pharmaceutical industries for which there have been few attempts for pesticide residue analysis reported in the literature. The proposed methodology is based on matrix solid phase dispersion (MSPD) using aluminum sulfate anh. a novel dispersant material and subsequent column chromatography clean-up in silica gel prior to gas chromatography (GC) with both flame photometric detector (FPD) and mass spectrometry (MS) detection used for the routine quantification and identification of the residues, respectively.

Transfer of pesticides to the brew during mate drinking process and their relationship with physicochemical properties.

In order to evaluate the extraction of pesticide residues that are transferred to the brew during mate drinking process of P.U.1 yerba mate leaves (Ilex paraguariensis), a special device to simulate the way in which mate is drunk in Uruguay was developed.