Heavy metal pollution is one of the most serious environmental problems, and regulations are becoming stricter. Many efforts have been made to develop sensors for monitoring heavy metals in the environment. This review aims at presenting the different label-free strategies used to develop electrochemical sensors for the detection of heavy metals such as lead, cadmium, mercury, arsenic etc. The first part of this review will be dedicated to stripping voltammetry techniques, on unmodified electrodes (mercury, bismuth or noble metals in the bulk form), or electrodes modified at their surface by nanoparticles, nanostructures (CNT, graphene) or other innovative materials such as boron-doped diamond. The second part will be dedicated to chemically modified electrodes especially those with conducting polymers. The last part of this review will focus on bio-modified electrodes. Special attention will be paid to strategies using biomolecules (DNA, peptide or proteins), enzymes or whole cells.

Beads, rings and mosaic tessarae from Tunisia (Carthage and Utica, 1st centuries BC and AD, El Djem, 2nd-3rd centuries and Mahdia, 10th century) were analysed by Raman spectroscopy for non-destructive differentiation of various types of glasses (most have Si-and Na/Ca-rich compositions, some others are lead-containing glass) and identification of synthetic or natural minerals (crystal or stone). The results are discussed in the light of chemical analyses. A green glass is coloured by a Cr-based nanosized pigment and a red mosaic tesserae is obtained by a colloidal dispersion of gold (Cassius purple). Cassiterite (SnO 2 ) is used as an opacifier or fluxing agent. The examination of glass mosaic and jewellery microstructure shows that some pieces are made of sintered glass, i.e. using a paste technology.

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Eight new sesquiterpenes, (ll), (12), (14)-(16), (18), (20) and (21), have been isolated from four separate small collections of the sponge Dysidea herbacea. The structures of these compounds, all of which contain a furan group, were derived by comparison of their spectral properties with those of known sesquiterpenes.