Verónica Gómez

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Solid-phase extraction (SPE) combined with liquid chromatography electrospray mass spectrometry (LC-(ESI)MS) was used to determine 16 non-ionic and anionic surfactants in different environmental water samples at ng L(-1) levels. The proposed method is sensitive and simple and has good linear range and detection limits (less than 50 ng L(-1)) for most(More)
A new set of covalent atomic radii has been deduced from crystallographic data for most of the elements with atomic numbers up to 96. The proposed radii show a well behaved periodic dependence that allows us to interpolate a few radii for elements for which structural data is lacking, notably the noble gases. The proposed set of radii therefore fills most(More)
The adsorption of three acid dyes, Acid Red 97, Acid Orange 61 and Acid Brown 425 onto activated carbon was studied for the removal of acid dyes from aqueous solutions at room temperature (25 degrees C). The adsorption of each dye with respect to contact time was then measured to provide information about the adsorption characteristics of activated carbon.(More)
In this paper we develop a suitable method for the speciation of chromium in tanning and environmental water samples. We use sequential injection analysis (SIA) with a diode array detector linked to chemometric tools such as multivariate curve resolution-alternating least squares (MCR-ALS) to determine Cr(III) and Cr(VI) species. Although Cr(III) is an(More)
Second-order calibration methods are gaining widespread acceptance among the analytical community mainly because: (1) a wide range of analytical instrumentation is available that enables high dimensionality data to be obtained; (2) the chemometric techniques for treating these data are highly developed; and (3) they have the so-called "second-order(More)
Reaction of the polysulfonated triazole ligand L = 4-(1,2,4-triazol-4-yl)ethanedisulfonate) with iron(II) salts in water yields the trimeric species [Fe3(μ-L)6(H2O)6](6-). This polyanion, as the dimethylammonium salt, shows a thermally induced spin transition above room temperature for the central Fe position in the trimer with a large hysteresis cycle (>85(More)
The reaction of 4-(1,2,4-triazol-4-yl)ethanesulfonate (L) with Zn(2+), Cu(2+), Ni(2+), Co(2+), and Fe(2+) gave a series of analogous neutral trinuclear complexes with the formula [M3(μ-L)6(H2O)6] (1-5). These compounds were characterized by single-crystal X-ray diffraction, thermogravimetry, and elemental analysis. The magnetic properties of compounds 2-5(More)
We used experimental design methodologies to obtain the response surface of the adsorption process for three acid dyes used in the dyeing step of a tanning process. The dyes were Acid Red 97, Acid Orange 61 and Acid Brown 425. The adsorption process was evaluated determining the concentrations of individual and total dyes remaining in solution at the end of(More)
We have developed a water-based synthesis for the preparation of 4-substituted 1,2,4-triazole ligands with highly polar functional groups. This general synthetic approach has allowed us to prepare two sulfonate functionalized 4-substituted 1,2,4-triazole anions ( L1(-)= 4-(1,2,4-triazol-4-yl)benzenesulfonate; L2(-)= 4-(1,2,4-triazol-4-yl)ethanesulfonate).(More)
The dimethylammonium salt of the FeII polyanionic trimer [Fe3(μ-L)6(H2O)6]6 ́ (L = 4-(1,2,4-triazol-4-yl)ethanedisulfonate) exhibits a thermally induced spin transition above room temperature with one of the widest hysteresis cycles observed in a spin crossover compound (>85 K). Furthermore, the metastable high-spin (HS) state can be thermally trapped via(More)