Screen-Printed Gold Electrodes as Passive Samplers and Voltammetric Platforms for the Determination of Gaseous Elemental Mercury.

We present a methodology for the determination of gaseous elemental mercury (GEM). It is based on passive sampling of Hg on screen-printed gold electrodes (SPGEs), followed by the measurement of amalgamated mercury by square wave anodic stripping voltammetry. We have explored in detail the behavior of the SPGE electrode surface during the sampling process (by time-of-flight secondary ion mass spectrometry), the stability of the voltammetric signals, and the inter-electrode reproducibility, and obtained acceptable results.

Nafion-Protected Sputtered-Bismuth Screen-Printed Electrode for On-site Voltammetric Measurements of Cd(II) and Pb(II) in Natural Water Samples.

In this work, we explore the protection with Nafion of commercial sputtered-bismuth screen-printed electrodes (BiSPEs), to improve its ability for on-site determination of Cd(II) and Pb(II) ions in ambient water samples. The modified screen-printed platform was coupled with a miniaturized cell, in combination with a battery-operated stirring system and a portable potentiostat operated by a laptop for decentralized electrochemical measurements using Square-Wave Anodic Stripping Voltammetry (SWASV). We also describe a detailed electrode surface characterization by microscopy and surface analysis techniques, before and after the modification with Nafion, to get insight about modification effect on signal size and stability.

Caesium-137 and strontium-90 temporal series in the Tagus River: experimental results and a modelling study.

The objective of this work consisted of analysing the spatial and temporal evolution of two radionuclide concentrations in the Tagus River. Time-series analysis techniques and numerical modelling have been used in this study. (137)Cs and (90)Sr concentrations have been measured from 1994 to 1999 at several sampling points in Spain and Portugal.