International audienceGold nanostructures (GNS) were chemically functionalized using four different diazonium salts: benzene-diazonium-tetrafluoroborate (DS), 4-decylbenzene-diazonium-tetrafluoroborate (DS-C10H21), 4-carboxybenzene-diazonium-tetrafluoroborate (DS-COOH), and 4-(aminoethyl)-benzene-diazonium-tetrafluoroborate (DS-(CH2)2NH2). Effective chemical grafting on GNS was shown by surface-enhanced Raman spectroscopy (SERS); aromatic ring deformations in the range of 1570–1591 cm–1 are of particular interest. The very strong band observed around 1075 cm–1, related to CH in-plane bending for mono- and para-substituted benzenes (coupled with ring-N stretching mode), provided further irrefutable evidence of the grafting. SERS enhancement of these two bands ascertains the perpendicular orientation of the aromatic rings on the GNS. X-ray photoelectron spectroscopy (XPS) analyses of chemically grafted flat gold surfaces suggest azophenyl radical pathways when using DS, DS-(CH2)2-NH2, or DS-C10H21. It was shown that coating at the interface is the result of a Au–N covalent bond; growth of the layers is via N═N. These XPS results agree with those provided by SERS without excluding the aryl radical pathways. For DS-COOH, the results provided by SERS, XPS, and density functional theory calculations show (i) effective chemical grafting of the GNS via a covalent bond between gold and carboxylate forms and (ii) growth via multilayers in the meta position between aromatic rings through either N═N or C–C bonds

An intercomparison exercise on passive samplers (PSs) was organized in summer 2010 to measure selected metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides in surface waters. Various PSs were used and compared at two river sites and one marine lagoon. A total of 24 laboratories participated. We present selected significant results from this exercise, including discussion on quality assurance and quality control for PSs, the interlaboratory variability of field blanks, time weighted average water concentrations and their uncertainties, the representativity of samples from Diffusive Gradient in Thin film, the ability of PSs to achieve lower limits of detection, PAH fingerprints in various PSs compared with spot samples, and the relevance of the permeability reference compound approach to the Polar Organic Chemical Integrative Sampler with pesticides. Highlights ► We present the first results from an intercomparison exercise on passive samplers. ► We discuss quality control and quality assurance strategy. ► We discuss the interlaboratory time weighted average (TWA) water concentrations. ► Through examples, we present the scope of some passive samplers (DGT, POCIS and SPMD). ► We discuss the permeability reference compounds approach to POCIS and pesticides.

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The aim of the paper is to compare two optical methods (UV spectrophotometry and laser granulometry) for a better knowledge of the behaviour of wastewater suspended solids. The first one, based on UV spectrophotometry, is used for the estimation of solids concentration and nature in water and wastewater with the help of an advanced exploitation method of UV spectra. But the interpretation of UV spectra, in presence of a very wide size distribution of solids is not always easy, because of the different phenomena responsible of light diffusion. The second method, more classical, allows to characterise the size distribution of particles.

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