Amperometric quantification based on serial dilution microfluidic systems.

This paper describes a microfluidic device fabricated in poly(dimethylsiloxane) that was employed to perform amperometric quantifications using on-chip calibration curves and on-chip standard addition methods. This device integrated a network of Au electrodes within a microfluidic structure designed for automatic preparation of a series of solutions containing an electroactive molecule at a concentration linearly decreasing. This device was first characterized by fluorescence microscopy and then evaluated with a model electroactive molecule such as Fe(CN(6))(4-).

Identification and simultaneous determination of Azorubin, Allura red and Ponceau 4R by differential pulse polarography: application to soft drinks.

Azorubin (E 122), Ponceau 4R (E 124) and Allura red (E 129), are the most used red dyes in soft drinks manufacturing, and in some cases two dyes are present. The aim of this work is to show that using differential pulse polarography, it was possible to distinguish these synthetic dyes from the natural dyes providing from fruits. In addition, in an appropriate supporting electrolyte, identification and quantitative analysis of these three red dyes were possible, even when they were mixed.

Potentiometric study of Cd(II) and Pb(II) complexation with two high molecular weight poly(acrylic acids); comparison with Cu(II) and Ni(II).

The cadmium (II) or lead (II) complex formation with two poly(acrylic acids) of high molecular weight (Mw=2.5 x 10(5) and 3 x 10(6)) was investigated in dilute aqueous solution (NaNO(3) 0.1 mol l(-1); 25 degrees C).

Potentiometric study of Cu(II) and Ni(II) complexation with two high molecular weight poly(acrylic acids).

The copper (II) or nickel (II) complex formation with two poly(acrylic acids) of high molecular weight (Mw=2.5x10(5) and 3x10(6)) was investigated in aqueous dilute solution (NaNO(3) 0.1 mol l(-1); 25 degrees C).

Label-free detection of bacteria by electrochemical impedance spectroscopy: comparison to surface plasmon resonance.

The low but known risk of bacterial contamination has emerged as the greatest residual threat of transfusion-transmitted diseases. Label-free detection of a bacterial model, Escherichia coli, is performed using nonfaradic electrochemical impedance spectroscopy (EIS). Biotinylated polyclonal anti-E.

Characterization of different diamond-like carbon electrodes for biosensor design.

Diamond-like carbon (DLC) films are gaining big interest in electrochemistry research area. DLC electrodes made with different ratio of sp(3)/sp(2) carbon hybridization or doped with different percentages of nickel were characterized electrochemically by cyclic voltammetry and by amperometric measurements towards hydrogen peroxide. SiCAr1 and SiCNi5% were chosen as sensitive transducers for the elaboration of amperometric glucose biosensors.

Amperometric and impedimetric characterization of a glutamate biosensor based on Nafion and a methyl viologen modified glassy carbon electrode.

An electrochemical biosensor based on a glassy carbon (GC) electrode chemically modified with the perfluorinated cation-exchange polymer Nafion and methyl viologen (MV) is described. The enzyme was immobilized by cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA), methyl viologen and Nafion. Operating variables such as the enzyme/BSA ratio, cross-linking time in glutaraldehyde vapor, methyl viologen and Nafion percentages were investigated with regard to their influence on the biosensor sensitivity by using glucose oxidase as the enzyme model due to its high stability and low cost.

Economic bismuth-film microsensor for anodic stripping analysis of trace heavy metals using differential pulse voltammetry.

Stripping analysis has been widely recognised as a powerful tool in trace metal analysis. Its remarkable sensitivity is attributed to the combination of a preconcentration step coupled with pulse measurements that generate an extremely high signal-to-background ratio. Mercury-based electrodes have traditionally been used to achieve high reproducibility and sensitivity in the stripping technique.

Rapid determination of mono and dinitrophenols by DPP, in the presence of lead and cadmium and using concentrated CaCl2 electrolyte.

The contamination of drinking water and industrial wastewaters is a critical environmental problem. The nitrophenol, dinitrophenol, cadmium, and lead contaminants are classified as hazardous compounds. Their rapid determination may be obtained using differential pulse polarography with concentrated electrolyte.

Electrochemical response of a carbon paste electrode containing an adsorbed species on incorporated alumina.

The electrochemical response of carbon paste electrode was investigated containing an inorganic and a non-electroactive compound on which an electro- active organic molecule was adsorbed. Alizarin S was chosen as the test molecule adsorbed on 150 m(2)/g of alumina, because this molecule is either easily reduced or oxidized on carbon. The electrode response was found to be linear for low amounts of alumina containing a known amount of Alizarin S.

[Diagnostic imaging of Budd-Chiari syndrome in adults and children].

Budd-Chiari syndrome is caused by the obstruction of the hepatic veins or of the inferior vena cava. It is characterized by the classic symptomatological triad: ascites, hepatomegaly, and abdominal pain. In 2/3 cases its etiology remains unknown.

A phase I study of human natural interferon-beta in cancer patients.

In this phase I study 15 patients with metastatic tumors were given interferon (IFN)-beta by i.v. bolus injections.

Venice: sea-lagoon exchange in a modified tide regime.

Salinity and tide heights recorded for a month at P(0), a point in the northern section of the Venetian lagoon, are the basic experimental data used to construct a numerical model which describes the salinity variations at P(0) as a function of the tides measured at the Lido entrance. The time variation of the salinity pattern iss interpreted in terms of a lagoon system in which a freshwater source of constant intensity is in a quasi-steady equilibrium with a tide-modulated sink. The mean residence time of a contaminant in this simulated lagoon is predicted from the change in the salinity pattern due to a reduction in the entrance size.