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4 results on '"M. Díaz-de-Alba"'

1. Disposable optical sensor for Al(III) ions determination by coupled colorimetric solid-phase extraction-reflectance spectroscopy in leachates from cookware, antacids and hygienic care products

Author

V. Castañeda-Loaiza, M.J. Casanueva-Marenco, M.D. Granado-Castro, M.D. Galindo-Riaño, and M. Díaz-de-Alba

Subjects
Pyridoxal, Diffuse reflectance infrared fourier transform, chemistry.chemical_element, 02 engineering and technology, 01 natural sciences, Analytical Chemistry, Adsorption, Aluminium, Limit of Detection, Solid phase extraction, Detection limit, Chromatography, Deodorants, 010401 analytical chemistry, Extraction (chemistry), Solid Phase Extraction, Hydrazones, Fractional factorial design, Water, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Spectrophotometry, Reagent, Solvents, Polystyrenes, Colorimetry, Antacids, 0210 nano-technology, Drug Contamination, Water Pollutants, Chemical, Aluminum
Abstract

A disposable and miniaturised optical sensor based on colorimetric solid-phase extraction has been designed using poly(styrene-divinylbenzene) membrane disks modified with the colorimetric reagent pyridoxal salicyloylhydrazone to determine the aluminium concentration in aqueous solutions. The extraction of Al(III) ions by the reagent immobilised onto a disk allows the quantification directly on the adsorbent surface by a miniature portable reflectance spectrometer with an optical fibre at 434 nm. The optimisation of the sensing system was carried out by a fractional factorial design 33−1 considering the extraction pH, amount of ligand immobilised onto the disk and time of immobilisation as experimental factors. The linear dynamic range of the sensor response ranged from 0.18 to 2 mg L−1 Al(III) with a detection limit of 0.18 mg L−1 (n = 10), being the precision of 6.3% for 1 mg L−1 Al(III) (n = 10, confidence level of 95%). The proposed method was successfully applied to the analysis of aluminium in leachates from cookware, antacids and hygienic care products, as contribution to the concern about aluminium as a known systemic toxicant at high doses.

Published
2019

2. Coupling liquid membrane and flow-injection technique as an analytical strategy for copper analysis in saline water

Author

M. Díaz-de-Alba, I. Chinchilla-Real, M.D. Granado-Castro, M.D. Galindo-Riaño, Manuel García-Vargas, and M.J. Casanueva-Marenco

Subjects
Detection limit, Flow injection analysis, Metal ions in aqueous solution, 010401 analytical chemistry, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Copper, 0104 chemical sciences, Analytical Chemistry, Matrix (chemical analysis), Certified reference materials, chemistry, Reagent, Seawater, 0210 nano-technology
Abstract

A tandem system based on the coupling of a bulk liquid membrane and a flow injection analysis for the separation, preconcentration and spectrophotometric determination of copper in saline water is presented. The ligand pyridine-2-acetaldehyde benzoylhydrazone has been used as a carrier in the liquid membrane as well as a spectrophotometric reagent for UV–VIS detection. Simultaneous and sequential experimental designs were used to optimise the chosen variables of each technique, respectively. The metal was separated and preconcentrated from the sample with an efficiency of 100.5 ± 0.9% and a metal preconcentration factor of 16.1. The on-line FIA determination was accomplished after metal complexation by the reagent at pH 3. A linear response was obtained in a range from 6.9 to 984.5 µg L–1 Cu(II), providing a detection limit of 1.8 µg L–1. Saline matrix and other metal ions were not cause of interferences with relative errors below 4.6% for 50 µg L−1 of Cu(II) determination. The proposed tandem system was successfully tested using a TMDA-62 certified reference material providing a relative error of + 1.9%; it was also applied to the Cu(II) determination in coastal seawater samples with low relative errors ranging from − 3.8% to 0.0% (using DPASV as reference method).

Published
2018

3. Coupling liquid membrane and flow-injection technique as an analytical strategy for copper analysis in saline water.

Author

Granado-Castro MD, Díaz-de-Alba M, Chinchilla-Real I, Galindo-Riaño MD, García-Vargas M, and Casanueva-Marenco MJ

Abstract

A tandem system based on the coupling of a bulk liquid membrane and a flow injection analysis for the separation, preconcentration and spectrophotometric determination of copper in saline water is presented. The ligand pyridine-2-acetaldehyde benzoylhydrazone has been used as a carrier in the liquid membrane as well as a spectrophotometric reagent for UV-VIS detection. Simultaneous and sequential experimental designs were used to optimise the chosen variables of each technique, respectively. The metal was separated and preconcentrated from the sample with an efficiency of 100.5 ± 0.9% and a metal preconcentration factor of 16.1. The on-line FIA determination was accomplished after metal complexation by the reagent at pH 3. A linear response was obtained in a range from 6.9 to 984.5 µg L -1 Cu(II), providing a detection limit of 1.8 µg L -1 . Saline matrix and other metal ions were not cause of interferences with relative errors below 4.6% for 50 µg L -1 of Cu(II) determination. The proposed tandem system was successfully tested using a TMDA-62 certified reference material providing a relative error of + 1.9%; it was also applied to the Cu(II) determination in coastal seawater samples with low relative errors ranging from - 3.8% to 0.0% (using DPASV as reference method)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Published
2019
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4. Solid phase extraction of copper traces using poly(styrene-divinylbenzene) membrane disks modified with pyridoxal salicyloylhydrazone in water samples.

Author

Díaz-de Alba M, Galindo-Riaño MD, and García-Vargas M

Abstract

A simple technique for the isolation, concentration and matrix simplification of Cu(II) ion in natural waters is proposed. This method has been developed using poly(styrene-divinylbenzene) membrane disks modified with the synthesized ligand pyridoxal salicyloylhydrazone (PSH). The retained ions on the disks were eluted with 10 mL 1 mol L(-1) HNO(3) and measured by flame atomic absorption spectrometry at 324.8 nm. The influence of pH, amount of ligand, type and amount of eluent for the stripping of copper ion from the membrane over extraction efficiency were evaluated. Extraction efficiencies >99% were obtained by elution of the disks with minimal amount of solvent with a preconcentration factor up to 100. The precision of the method for 10 replicate measurements of aqueous solutions containing 40 μg L(-1) Cu(II) was 1.5% at significance level of 95%. The breakthrough volume for 5 μg of Cu(II) was found to be 1000 mL and the detection limit of the method was 4 ng L(-1) of metal ion. The present method was successfully applied to the extraction and determination of copper in lake and sea waters., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Published
2012
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