Biomedical subjects

Victoria Salvadó

Publications and source records attributed to Victoria Salvadó.

4 recordsLinked to original sources

PubMed2006

Ethanol/Water extraction combined with solid-phase extraction and solid-phase microextraction concentration for the determination of chlorophenols in cork stoppers.

The appearance of 2,4,6-trichloroanisole (TCA) in cork stoppers is of great concern because it can cause off-flavors in bottled wine. To prevent this sensorial defect, there should not be any traces of 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP), or pentachlorophenol (PCP) in the finished corks, because they are the direct precursors of TCA. In the course of this study two methodologies based upon an extraction with ethanol/water mixtures to determine the chlorophenolic content in cork matrices were developed. The cork extract is preconcentrated using both solid-phase extraction and solid-phase microextraction methodologies. The latter was optimized by applying a full two-level factorial design. Finally, spiked ground corks at nanogram per gram levels of each chlorophenol were analyzed under optimal conditions and by applying both procedures. The obtained results demonstrate that chlorophenols can be detected in corks contaminated at the nanogram per gram level and, thus, these approaches can be successfully applied as quality control measures in the cork industry.

Chlorophenols↗

PubMed2004

Evaluation of a new solid-phase cartridge for the preconcentration of phenolic compounds in water.

The aim of this study is to evaluate the efficiency of a new solid-phase extraction cartridge, Spe-ed Advanta, in the extraction and preconcentration of four phenolic compounds (phenol, 2-chlorophenol, 2-nitrophenol, and 2,4-dichlorophenol) from water. The solid phase is a polystyrene-divinylbenzene resin modified with carboxylic groups, these polar groups improve the contact between the matrix and the aqueous solutions in the extraction of polar analytes. We studied several elution solvents in order to find the most efficient one. Sample concentration, sample volume, and sample pH are also investigated as well as the best method for drying the cartridge. Recoveries achieved with the new phase are compared with those obtained with Isolute ENV+, a non-modified polystyrene-divinylbenzene stationary bed. The best experimental conditions were then used for determination of the phenols in spiked environmental waters.

Chlorophenols↗

PubMed2003

Comparison of nutrient and contaminant fluxes in two areas with different hydrological regimes (Empordà Wetlands, NE Spain).

Nutrient (N and P), heavy metal (Ni, Cd, Cr, Cu and Pb) and pesticide (DDT, DDD, DDE, lindane, aldrin, endrin, dieldrin, permethrin, atrazine and simazine) concentrations in water and sediment were analysed in the Empordà Wetlands, a Mediterranean wetland area in NE Spain. Mean nutrient and contaminant concentrations and input and output loads via tributaries were compared in two marshes with different water turnover: a freshwater marsh (FWM), with a high water turnover rate due to continuous surface water inputs and outputs, and a brackish water marsh (BWM), with lower turnover and no continuous surface output, where water remains confined during dry periods. Mean concentrations of most heavy metals exceeded the maximum permissible concentration (MPC) in BWM, whilst only some pesticides reached MPC in FWM. The confined waters of BWM showed higher sensitivity to contaminant input loadings than FWM due to the lack of continuous water outputs. Non-point source pollution inputs during runoff (mainly in FWM) and concentration during confinement (mainly in BWM) showed as the main environmental problems related to nutrients and contaminants in these ecosystems. Thus, the importance of confinement and its effect on pollutant concentrations must be borne in mind to achieve correct management of Mediterranean wetlands.

Ecosystem↗

PubMed2002

Comparison of micellar and microemulsion electrokinetic chromatography for the analysis of water- and fat-soluble vitamins.

Separation and determination of water- and fat-soluble vitamins by micellar (MEKC) and microemulsion electrokinetic chromatography (MEEKC) are compared. MEKC is only useful in the quantitative analysis of water-soluble vitamins when sodium dodecylsulfate (SDS) is used as the surfactant. However, the separation of mixtures containing water- and fat-soluble vitamins is only achieved by MEEKC using a microemulsion prepared by mixing SDS as the surfactant, butanol as the co-surfactant, octane as the non-polar modifier and propanol as the second co-surfactant. The injection time and the solvent used for the dilution of samples have a significant effect on the analysis of lypophilic compounds. The most reproducible results in the analysis of fat-soluble vitamins are obtained by using the same microemulsion electrolyte as the solvent for samples and an injection time of 10 s.

Chromatography, Micellar Electrokinetic Capillary↗