20 documents found, page 1 of 2
Structural description of humic substances from subtropical coastal environment...
Sierra, M. M.D.; Giovanela, M.; Parlanti, E.; Esteves, V. I.; Duarte, A. C.; Fransozo, A. [UNESP]; Soriano-Sierra, E. J.Made available in DSpace on 2022-04-28T20:01:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-01-01; Elemental composition and spectroscopic properties (FT-IR and CP/MAS 13C-NMR) of sedimentary humic substances (HS) from aquatic subtropical environments (a lake, an estuary and two marine sites) are investigated. Humic acids (HA) are relatively richer in nitrogen and in aliphatic chains than fulvic acid...
Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estu...
Otero, M.; Coelho, J. P.; Rodrigues, E. T.; Pardal, M. A.; Santos, E. B. H.; Esteves, V. I.; Lillebo, A. I.In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The ...
Development of an enzyme-linked immunosorbent assay for atrazine monitoring in ...
Lima, D. L. D.; Schneider, R. J.; Esteves, V. I.The implementation of the Water Framework Directive (2000/60/EC) requires the establishment of monitoring programs. However, conventional procedures for sample preparation prior to chromatographic analysis are rather expensive and time consuming, being the development of cost-effective and easy tool a necessity. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) able to determine a...
Characterization of Brazilian peat samples by applying a multimethod approach
Girardello, F.; Guégan, R.; Esteves, V. I.; Baumvol, I. J. R.; Sierra, M. M. D.; Crespo, J. S.; Fernandes, A. N.; Giovanela, M.Peat is a mixture of compounds formed by the decomposition of plant residues and mineral materials that have accumulated at the bottom of ponds and flooded depressions in riverine areas. Due to their extreme heterogeneity and natural variety, the physical and chemical properties of peat can vary widely within or between deposits, and the characterization of isolated samples is still a challenging task that requ...
BDE-209: kinetic studies and effect of humic substances on photodegradation in ...
Leal, J. F.; Esteves, V. I.; Santos, E. B. H.BDE-209 is a brominated flame retardant and a priority contaminant, which has been found in several environmental matrices, namely, in water. To date, there are no quantum yield data for BDE-209 photodegradation by sunlight in water, to allow predicting half-life times in aquatic systems. In this work, the kinetics of BDE-209 photodegradation in water was studied and the influence of different fractions of aqua...
Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estu...
Otero, M.; Coelho, J. P.; Rodrigues, E. T.; Pardal, M. A.; Santos, E. B. H.; Esteves, V. I.; Lillebø, A. I.In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The ...
Noise normalisation in capillary electrophoresis using a diode array detector
Erny, G. L.; Calisto, V.; Esteves, V. I.When using capillary electrophoresis with a diode array detector, the wavelength at maximum absorbance is often chosen to quantify a given analyte. However, the background noise for every wavelength should be taken into account as it is by maximising the signal to noise ratio that the lowest limit of detection will be obtained. Here, we proposed an algorithm allowing to correct an electropherogram from its back...
Adsorption behavior of 17 alpha-ethynylestradiol onto soils followed by fluores...
Lima, D. L. D.; Calisto, V.; Esteves, V. I.In this study, a simple and rapid procedure for monitoring adsorption of 17 alpha-ethynylestradiol (EE2) onto soil samples was developed. The used method is based on a multiwavelength fluorescence spectral deconvolution (FSD) where the emission fluorescence spectrum of a sample is considered as a linear combination of emission spectra, named reference spectra. The combination of the reference spectra allows the...
Development of an ELISA procedure to study sorption of atrazine onto a sewage s...
Lima, D. L. D.; Silva, C. P.; Schneider, R. J.; Esteves, V. I.Pesticides may contaminate ground and surface waters and one of the major factors governing this property is soil sorption. Sorption can be assessed by batch equilibrium technique which produces lots of extracts with high dissolved organic carbon concentration in which the pesticide concentration has to be determined. We developed an ELISA procedure to analyse atrazine based on polyclonal antibodies (C193) for ...
Effect of long term organic amendments on adsorption-desorption of thiram onto ...
Filipe, O. M. S.; Vidal, M. M.; Scherer, H. W.; Schneider, R. J.; Duarte, A. C.; Esteves, V. I.; Santos, E. B. H.The objective of this work was to assess the influence of soil organic amendments on the sorption properties of the fungicide thiram. The organic amendments studied were organic household compost (COM), sewage sludge from municipal water treatment facilities (SLU) and farmyard manure (FYM), which were compared to mineral fertilizer application (MIN). Sorption-desorption experiments were performed using the batc...