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Nafion coated glassy carbon electrodes (NCE) are employed for preconcentrating and detecting Fe2+ and Fe3+ cations from aqueous solutions. The influence of the supporting electrolyte composition and of the redox state on the analyte partitioning within the Nafion coating are examined. By using cyclic voltammetry, the ion‐exchange voltammetric determination of iron in the μM concentration range is achieved from voltammetric peak currents relevant to the reversible redox process: Fe3++e⇋Fe2+. Depending on the starting potential of the voltammetric scan, all the iron is initially converted to the Fe(III) or Fe(II) redox state, so that, from the voltammogram, the overall concentration of iron is always obtained. However, the simple measurement of the open circuit potential at the NCE before starting the scan allows one to get information on the ratio between Fe(III) and Fe(II) incorporated in the Nafion coating. From relevant ion‐exchange distribution coefficients, open circuit potential values can be related to the Fe(III)/Fe(II) concentration ratio in the sample. The use at the NCE of a new electroanalytical technique named multiple square‐wave voltammetry in the double differential mode allows the significative lowering of detection limits pushing the operative range of the method in the nM range. Application to analysis of Fe(II) in the pore‐waters of sediments of the lagoon of Venice (Italy) is presented.

A new prototype pore-water sampler is proposed which allows temporal sampling of pore-water from intertidal sediments. The system consists of a nylon device provided with regularly spaced chambers, double filtering ports and pipes for in-situ sample recovering. The field use of this apparatus for determining sulfur species in pore-waters is described; a satisfactory agreement between data obtained by using the proposed in-situ sampler and by core-squeezing in proper experimental conditions is found. Finally, advantages and differences with respect to other in-situ samplers are critically evaluated.

Twenty‐six wall painting fragments and some plaster, ‘intonachino’ and stucco samples, discovered at Iulia Concordia, have been studied by different analytical techniques to gain information about the pigment nature and the composition of the materials. The presence of calcite, dolomite and aragonite allow the distinction of four groups of wall samples varying in the nature of pigments and in the application technique. These differences can be attributed to different execution times or, more probably, to the arrangement of the rooms in the building structure. The nature of the pigments found in the Thermae of Iulia Concordia appears similar to that found in other Roman villas of Venetia et Histria, with the use of precious pigments such as Egyptian blue and cinnabar.