Alicia Sánchez
University of the Basque Country
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Publication
Featured researches published by Alicia Sánchez.
Journal of Pharmaceutical and Biomedical Analysis | 2008
Nora Unceta; Alberto Gómez-Caballero; Alicia Sánchez; Silvia Millán; M. Carmen Sampedro; M. Aranzazu Goicolea; Joan Sallés; Ramón J. Barrio
A liquid chromatography method was developed for the determination of some frequently prescribed selective serotonin re-uptake inhibitors (SSRI) - citalopram and fluoxetine - and its main metabolites - demethylcitalopram, didemethylcitalopram and norfluoxetine - in human urine samples, using a previous stage of solid-phase microextraction. All the extraction parameters influencing adsorption (extraction time, temperature, pH, ion strength and organic modifier addition) and desorption (desorption time and desorption solvent mixture composition) of the analytes on the fiber have been studied. A satisfactory reproducibility for extraction from urine samples (R.S.D.<10%) was obtained. The linearity for urine ranged from 0.05 to 2 mg l(-1) with limits of detection close to 0.01 mg l(-1), which cover the typical urinary concentrations obtained for citalopram, fluoxetine and their metabolites.
Journal of Pharmaceutical and Biomedical Analysis | 2010
Nora Unceta; Ana Ugarte; Alicia Sánchez; Alberto Gómez-Caballero; M.A. Goicolea; Ramón J. Barrio
The aim of this article is to present an analytical application of stir bar sorptive extraction (SBSE) coupled to HPLC-fluorescence detection (FLD) for the quantification of fluoxetine (FLX), citalopram (CIT) and venlafaxine (VLF) and their active metabolites - norfluoxetine (NFLX), desmethyl- (DCIT) and didesmethylcitalopram (DDCIT) and o-desmethylvenlafaxine (ODV) - in plasma, urine and brain tissue samples. All the parameters influencing adsorption (pH, ion strength, organic modifier addition, volume, extraction time and temperature) and desorption (desorption solvent composition, time, temperature and desorption mode) of the analytes on the stir bar have been optimized. For each matrix, the analytical method has been assessed by studying the linearity and the intra- and interday accuracy (89-113%) and precision (RSD<13%). The improvement of the quantification limits (0.2-2 microg l(-1) for plasma, 2-20 ng g(-1) for brain tissue and 1-10 microg l(-1) for urine, depending on the respective response for analytes) and the development of a procedure for all the matrices make this method useful in clinical and forensic analysis.
Forensic Science International | 2015
Sandra Benito; Zuriñe Abrego; Alicia Sánchez; Nora Unceta; M. Aranzazu Goicolea; Ramón J. Barrio
The identification of characteristic organic gunshot residues (OGSR) provides conclusive evidence in the elucidation of elemental profiles when lead-free ammunition is fired. OGSR also prevents false negatives. Toward this aim, a quick and efficient method based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF) was developed to detect and identify 18 gunpowder additives in gunshot residues (GSR). The unequivocal identification of target analytes was assured by using MS/MS mode. Swabs were compared with home-modified tape lift supports covered with a PTFE layer to determine the better sampling technique. The modified tape lift provided better extraction recoveries and enabled the analysis of inorganic and organic GSR simultaneously. The developed method was applied to the analysis of GSR from four different lead-free ammunitions. Diphenylamine and its nitrated degradation products and centralites were identified in all samples, providing strong evidence of GSR.
Journal of Chromatography A | 2016
Laura Millán; M. Carmen Sampedro; Alicia Sánchez; Cédric Delporte; Pierre Van Antwerpen; M. Aranzazu Goicolea; Ramón J. Barrio
Grapevine and derived products are rich in a wide range of compounds and its quality mainly depends on its metabolites, as a result of viticulture practices. Plant sterols, also called phytosterols (PS), are secondary metabolites regarded as bioactive substance present in grape berries and other plant-based food. The present study deals with a metabolomic approach focusing on phytosterols family in six varieties of Rioja grapes (Cabernet Sauvignon, Tempranillo, Graciano, Garnacha, White Garnacha and Viura), in order to find significant differences among them. Liquid chromatography- mass spectrometry with a quadrupole-time of flight mass analyzer (LC-QTOF) was used to find as many metabolites as possible in the different grape berry fractions, and using statistics to help finding significant clustering of the metabolic profile of pulp, peel and seeds in relation to the variety. The best chromatographic and detection conditions were achieved by gas phase ionization via atmospheric pressure chemical ionization (APCI) in positive mode. Furthermore, analysis with electrospray (ESI) is also needed for phytosterol derivatives confirmation. Putative compounds of interest in the analyzed samples were found by an automated compound extraction algorithm (Molecular Feature Extraction, MFE) and an initial differential expression from the data was created with the aid of commercial software. Once the data were collected, the results were filtered, aligned and normalized, and evaluating applying one-way analysis of variance (ANOVA) with a 95% significance level. For sample class prediction, partial least square-discriminant analysis (PLS-DA) is used as a supervised pattern recognition method and excellent separation among the grape varieties is shown. An overall accuracy of 93.3% (pulp samples), 100.0% (peel) or 96.7% (seeds) in discriminating between grape varieties was achieved when comparing the different fractions. In general, 7 PS derivatives were identified with ID scores higher than 84%.
Analyst | 2014
Zuriñe Abrego; Nagore Grijalba; Nora Unceta; Maite Maguregui; Alicia Sánchez; Alberto Fernández-Isla; M. Aranzazu Goicolea; Ramón J. Barrio
Journal of Chromatography A | 2008
Alicia Sánchez; Silvia Millán; M. Carmen Sampedro; Nora Unceta; Esther Rodríguez; M. Aranzazu Goicolea; Ramón J. Barrio
Analytical and Bioanalytical Chemistry | 2016
Sandra Benito; Alicia Sánchez; Nora Unceta; Fernando Andrade; Luis Aldámiz-Echevarría; M.A. Goicolea; Ramón J. Barrio
Biomedical Chromatography | 2008
Silvia Millán; M.A. Goicolea; Alicia Sánchez; Alberto Gómez-Caballero; M.C. Sampedro; Nora Unceta; Ramón J. Barrio
Journal of Food Composition and Analysis | 2015
Laura Millán; M. Carmen Sampedro; Alicia Sánchez; M. Aranzazu Goicolea; Ramón J. Barrio
Analyst | 2017
Zuriñe Abrego; Nora Unceta; Alicia Sánchez; Alberto Gómez-Caballero; Luis Maria Berrio-Ochoa; M. Aranzazu Goicolea; Ramón J. Barrio