Search results for: J.M. Estela

Items from 1 to 14 out of 14 results

article

Solid phase extraction – Multisyringe flow injection system for the spectrophotometric determination of selenium with 2,3-diaminonaphthalene

A.M. Serra, J.M. Estela, B. Coulomb, J.L. Boudenne, more

Talanta > 2010 > 81 > 1-2 > 572-577

In the present work, a solid phase extraction (SPE) is hyphenated with an automatic MSFIA system to improve the selenite determination based on the reaction of selenite with aromatic o-diamines (such as 2,3-diaminonaphthalene (DAN)) to form the piazselenol complex. This reaction is greatly influenced by acid concentration, temperature, the time needed for colour development, and presence of foreign...

article

An MSFIA system for mercury speciation based on an anion-exchange membrane

A.M. Serra, J.M. Estela, V. Cerdà

Talanta > 2009 > 78 > 3 > 790-794

A new methodology for the in-line preconcentration, clean-up and speciation of mercury by use of an anion-exchange membrane is proposed. The speciation of mercury is based on retention of its tetrachloro complex onto the membrane while organic mercury flows freely through it. A multisyringe is used as a liquid driver and a cold vapour atomic fluorescence detector is employed to ensure a high sensitivity...

article

Contribution of multi-commuted flow analysis combined with monolithic columns to low-pressure, high-performance chromatography

H.M. González-San Miguel, M. Fernández, J.M. Estela, V. Cerdà

Trends in Analytical Chemistry > 2009 > 28 > 3 > 336-346

The advent of monolithic columns has facilitated the combination of chromatographic techniques with non-separation flow techniques [particularly sequential injection analysis (SIA) and multi-syringe flow-injection analysis (MSFIA)] by virtue of the low overpressure introduced by monolithic columns. So far, these combinations have provided excellent results derived from the high selectivity of liquid...

article

MSFIA system for mercury determination by cold vapour technique with atomic fluorescence detection

A.M. Serra, J.M. Estela, V. Cerdà

Talanta > 2008 > 77 > 2 > 556-560

A new multisyringe flow injection analysis system for mercury determination using cold vapour technique assembling with atomic fluorescence spectrometry is proposed.The system consists of a multisyringe module as liquid driver, a gas–liquid separator, a gas dryer device and an atomic fluorescence detector. As reducing agent, 1% tin chloride solution is used. Standard solutions and carrier are prepared...

article

Potential of multisyringe flow-based multicommutated systems

V. Cerdà, R. Forteza, J.M. Estela

Analytica Chimica Acta > 2007 > 600 > 1-2 > 35-45

This work is aimed at emphasizing the potential of the multicommutated systems based on the multisyringe flow injection analysis (MSFIA) modality. First, the characteristics, advantages and withdraws offered by flow analysis systems based on the different non-segmented modalities are briefly described. In these systems, multicommutation and computer control of the analytical process occupy a predominant...

article

Monitoring of environmental parameters by sequential injection analysis

V. Cerdà, A. Cerdà, A. Cladera, M.T. Oms, more

Trends in Analytical Chemistry > 2001 > 20 > 8 > 407-418

The use of sequential injection analysis (SIA), as applied to the control of environmental parameters, is reviewed. Its advantages and drawbacks are compared with those of flow injection analysis (FIA). FIA is simpler and easier to handle, has a higher sample throughput, and may be controlled manually, but SIA is more robust and versatile and better adapted for multiparametric and stopped flow techniques.

article

Sequential injection analysis for the determination of fuberidazole and thiabendazole by variable-angle scanning fluorescence spectrometry

G. de Armas, E. Becerra, A. Cladera, J.M. Estela, more

Analytica Chimica Acta > 2001 > 427 > 1 > 83-92

A study of the behaviour of fuberidazole (FBZ) (2-(2'-furyl)benzimidazole), and thiabendazole (TBZ) (2-(thiazol-4-yl)benzimidazole) in a sequential injection system with a fluorimetric detector has been performed. Several variables such as pH, composition of buffers, volumes of sample and reagents, addition order, geometry of mixing coil and spectrofluorimetric parameters have been optimised. A pH...

article

Fluorimetric sequential injection determination of magnesium using 8-hydroxiquinoline-5-sulfonic acid in a micellar medium

G. de Armas, A. Cladera, E. Becerra, J.M. Estela, more

Talanta > 2000 > 52 > 1 > 77 - 82

A fluorimetric sequential injection method for the determination of magnesium is proposed. The system is based on the complex formation between Mg(II) and 8-hydroxyquinoline-5-sulfonic acid (HQS). The reaction was carried out in the presence of ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) as a masking agent. Cetyltrimethylammonium chloride (HTAC) was employed as a fluorescence...

article

Evaluation of spectrophotometric methods for determination of orthophosphates by sequential injection analysis

A. Muñoz, F. Mas Torres, J.M. Estela, V. Cerda

Analytica Chimica Acta > 1997 > 350 > 1-2 > 21-29

Three methods for the determination of orthophosphate have been studied by using the same sequential injection analysis manifold, namely the vanadomolybdate, the Malachite Green and the molybdenum blue methods. The calibration graphs were linear up to 18.0, 0.4 and 4.0 mg P l ^- ¹ , respectively. Relative standard deviations and detection limits for vanadomolybdate, Malachite Green and...

article

Resolution of highly overlapping differential pulse anodic stripping voltammetric signals using multicomponent analysis and neural networks

A. Cladera, J. Alpízar, J.M. Estela, V. Cerdà, more

Analytica Chimica Acta > 1997 > 350 > 1-2 > 163-169

This paper reports and discusses the results obtained by using multicomponent analysis methods based on multiple linear regression and neural network procedures to resolve highly overlapping signals obtained by differential pulse anodic stripping voltammetry by using a static drop electrode. The former procedures were applied to the well-known chemical model composed of Pb(II), Tl(I), In(III) and...

article

Effect of variables influencing S ₁ ₂ in sequential injection analysis. Extrapolability of S ₁ ₂ based results between SIA designs

A. Cladera, E. Gómez, J.M. Estela, V. Cerdà

Talanta > 1996 > 43 > 10 > 1667-1674

The influence of variables including ionic strength, propulsion rate and instrumental design parameters on dispersion in a sequential injection analysis system was studied via S ₁ ₂ and several other parameters related to the dispersion profile. The influence of such parameters on a real system was evaluated in the reaction of Fe(II) witho -phenanthroline by optimizing various instrumental...

article

Development and testing of a new computerized method for multicomponent kinetic determinations based on multiwavelength spectrophotometric detection

J.M. Estela, A. Cladera, V. Cerdà

Analytica Chimica Acta > 1995 > 310 > 2 > 307-318

We developed a new kinetic multidetermination method based on multiwavelength spectrophotometric detection and used simulated processes to evaluate its performance. The method uses spectral differences between analytes and kinetic equations solved by means of a nonlinear regression procedure. It allows the simultaneous determination of rate constants and analyte concentrations, and takes account...

article

A new instrumental implementation of sequential injection analysis

A. Cladera, C. Tomàs, E. Gómez, J.M. Estela, more

Analytica Chimica Acta > 1995 > 302 > 2-3 > 297-308

The performance of a new system for sequential injection analysis equipped with a liquid driver constituted by an ordinary burette for conventional automatic titrations actuated by a stepper motor was assessed. The proposed system circumvents the high cost of conventional liquid drivers and the problems typically posed by highly absorbing chromogenic reagents, which provide a varying background in...

article

Calculation and refinement of thermodynamic parameters from thermometric titrations. II. The neutralization enthalpies of phenols in hydro-alcoholic media

R. Forteza, A. Caro, J.M. Estela, V. Cerdà

Thermochimica Acta > 1995 > 268 > 105-120

Several monoprotic and polyprotic phenols were analysed by thermometric titration in a 50:50 v/v methanol/water medium. The performance of various methods for the calculation and refinement of thermodynamic parameters from thermometric titration data in the determination of the neutralization enthalpies of several phenols in hydro-alcoholic media is compared in terms of precision and the influence...

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Keywords

SEQUENTIAL INJECTION ANALYSIS (5)
MSFIA (3)
S 1 2 (1)
2,3-DIAMINONAPHTHALENE (1)
8-HYDROXYQUINOLINE-5-SULFONIC ACID (1)
ANION-EXCHANGE MEMBRANE (1)
ANODIC STRIPPING VOLTAMMETRY (1)
ATOMIC FLUORESCENCE (1)
COLD VAPOUR (1)
COLD VAPOUR ATOMIC FLUORESCENCE SPECTROMETRY (1)
COMPUTERIZED METHODS (1)
EGTA (1)
ENVIRONMENTAL MONITORING (1)
FLOW ANALYSER (1)
FLOW INJECTION ANALYSIS (1)
FLOW SYSTEM (1)
FLOW TECHNIQUES (1)
FUBERIDAZOLE (1)
HG DETERMINATION (1)
HYDRO-ALCOHOLIC MEDIA (1)
KINETIC METHODS (1)
LOW-PRESSURE, HIGH-PERFORMANCE CHROMATOGRAPHY (1)
MAGNESIUM (1)
MEMBRANE DISK (1)
MERCURY SPECIATION (1)
MONOLITHIC COLUMN (1)
MSC (1)
MULTI-SYRINGE CHROMATOGRAPHY (1)
MULTI-SYRINGE FLOW-INJECTION ANALYSIS (1)
MULTICOMPONENT ANALYSIS (1)
MULTIPLE LINEAR REGRESSION ANALYSIS (1)
NEURAL NETWORKS (1)
NEUTRALIZATION ENTHALPIES (1)
NON-SEPARATION FLOW TECHNIQUE (1)
PHENOLS (1)
PHOSPHATE (1)
PIAZSELENOL (1)
SAMPLE TREATMENT (1)
SELENITE (1)
SEQUENTIAL INJECTION (1)
SEQUENTIAL INJECTION ANALYSIS (SIA) (1)
SEQUENTIAL INJECTION CHROMATOGRAPHY (1)
SIC (1)
SOLID PHASE EXTRACTION (1)
SPECTROFLUORIMETRY (1)
SPECTROPHOTOMETRY (1)
THERMOMETRIC TITRATION (1)
THIABENDAZOLE (1)
VARIABLE-ANGLE FLUORESCENCE SPECTROMETRY (1)
WASTEWATER (1)
WATER ANALYSIS (1)
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INFONA - science communication portal

Search results for: J.M. Estela

Solid phase extraction – Multisyringe flow injection system for the spectrophotometric determination of selenium with 2,3-diaminonaphthalene

An MSFIA system for mercury speciation based on an anion-exchange membrane

Contribution of multi-commuted flow analysis combined with monolithic columns to low-pressure, high-performance chromatography

MSFIA system for mercury determination by cold vapour technique with atomic fluorescence detection

Potential of multisyringe flow-based multicommutated systems

Monitoring of environmental parameters by sequential injection analysis

Sequential injection analysis for the determination of fuberidazole and thiabendazole by variable-angle scanning fluorescence spectrometry

Fluorimetric sequential injection determination of magnesium using 8-hydroxiquinoline-5-sulfonic acid in a micellar medium

Evaluation of spectrophotometric methods for determination of orthophosphates by sequential injection analysis

Resolution of highly overlapping differential pulse anodic stripping voltammetric signals using multicomponent analysis and neural networks

Effect of variables influencing S ₁ ₂ in sequential injection analysis. Extrapolability of S ₁ ₂ based results between SIA designs

Development and testing of a new computerized method for multicomponent kinetic determinations based on multiwavelength spectrophotometric detection

A new instrumental implementation of sequential injection analysis

Calculation and refinement of thermodynamic parameters from thermometric titrations. II. The neutralization enthalpies of phenols in hydro-alcoholic media

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