M. Julia Arcos Martínez

Determination of lamotrigine by adsorptive stripping voltammetry using silver nanoparticle-modified carbon screen-printed electrodes.

Carbon screen-printed electrodes (CSPE) modified with silver nanoparticles present an interesting alternative in the determination of lamotrigine (LTG) using differential pulse adsorptive stripping voltammetry. Metallic silver nanoparticle deposits have been obtained by electrochemical deposition. Scanning electron microscopy measurements show that the electrochemically synthesized silver nanoparticles are deposited in aggregated form. The detection limit for this analytical procedure was 3.72 x 10(-7) M. In terms of reproducibility, the precision of the above mentioned method in %R.S.D. values was calculated at 2.58%. The method was applied satisfactorily to the determination of LTG in pharmaceutical preparations.

Speciation of antimony by adsorptive stripping voltammetry using pyrogallol

This paper describes a new procedure for the determination of Sb (III) and Sb (V) by differential pulse adsorptive stripping voltammetry (DPAdSV) using pyrogallol as a complexing agent. The selection of the experimental conditions was made using experimental design methodology. The detection limits obtained were 1.03x10(-10) and 9.48x10(-9)mol dm(-3) for Sb (III) and Sb (V), respectively. In order to carry out the simultaneously determination of both antimony species a partial least squares regression (PLS) is employed to resolve the voltammetric signals from mixtures of Sb (III) and Sb (V) in the presence of pyrogallol. The relative error in absolute value is less than 0.5% when concentrations of several mixtures are calculated. Moreover, the solution is analyzed for any possible effects of foreign ions. The procedure is successfully applied to the speciation of antimony in pharmaceutical preparations and water samples.

Simultaneous determination of antimony(III) and antimony(V) by UV–vis spectroscopy and partial least squares method (PLS)

This paper describes a procedure for the speciation of antimony by UV-vis spectroscopy using pyrogallol as complexing agent. A partial least squares (PLS) regression was performed to resolve highly overlapping spectrophotometric signals obtained from mixtures of Sb(III) and Sb(V). The relative error in absolute value was less than 5% when concentrations of several mixtures were calculated. The minimum concentration determined was 3.96x10(-5)moldm(-3) and 3.98x10(-5)moldm(-3) for Sb(V) and Sb(III), respectively. The analysis of the possible effect of the presence of foreign ions in the solution was performed and the procedure was successfully applied to the speciation of antimony in pharmaceutical preparations and aqueous samples.