Mission conjointe NMA/PRIFAS d´étude et de prospective dans Le Sudeste du Bresil, du 27 octobre au 10 novembre 1990.

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Synthesis of 14C-labelled polystyrene nanoplastics for environmental studies

AbstractAvailable analytical methods cannot detect nanoplastics at environmentally realistic concentrations in complex matrices such as biological tissues. Here, we describe a one-step polymerization method, allowing direct radiolabeling of a sulfonate end-capped nano-sized polystyrene (nPS; proposed as a model nanoplastic particle representing negatively charged nanoplastics). The method, which produces nanoplastics trackable in simulated environmental settings which have already been used to investigate the behavior of a nanoplastic in vivo in a bivalve mollusc, was developed, optimized and successfully applied to synthesis of 14C-labeled nPS of different sizes. In addition to a description of the method of synthesis, we describe the details for quantification, mass balance and recovery of the labelled particles from complex matrices offered by the radiolabelling approach. The radiolabeling approach described here, coupled to use of a highly sensitive autoradiographic method for monitoring nanoplastic body burden and distributions, may provide a valuable procedure for investigating the environmental pathways followed by negatively charged nanoplastics at low predicted environmental concentrations. Whether the behaviour of the synthetic nPS manufactured here, synthesised using a very common inititator, represents that of manufactured nPS found in the environment, remains to be seen.</jats:p

Environmental effects of ozone depletion, UV radiation and interactions with climate change : UNEP Environmental Effects Assessment Panel, update 2017

Peer reviewe

Compte rendu de mission au Bresil du 8 au 22 decembre 1992.

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Hyphenated analytical techniques for multidimensional characterisation of submicron particles: A review

cited By 38International audienceThe stakes concerning the characterisation of particles ranged in the size from 1 to 1000. nm, namely submicron particles, are today more and more important. Because of the variety of particles even inside a given sample in terms of dimension, mass, charge or chemical composition a characterisation as complete as possible is needed. The possibility of obtaining a multidimensional information by relevant analytical methods is then of the greatest interest. One very interesting strategy consists in using hyphenated techniques, which are intrinsically capable to provide rapidly and accurately such information. This paper summarises the different hyphenated techniques that can be used to characterise submicron particles and is focussed on their main applications to illustrate their current and potential uses. In order to have a relevant overview various on-line separation techniques are considered in a comparative way. In the same way various on-line detectors are then presented. Finally the concepts of multidetection and multidimensional analysis are discussed and their interest showed through different typical examples of hyphenated techniques illustrating submicron particle characterisation in fields of applications such as environmental and nanomaterial sciences. © 2011 Elsevier B.V

Size characterization of the associations between carbon nanotubes and humic acids in aqueous media by asymmetrical flow field-flow fractionation combined with multi-angle light scattering

cited By 9International audienceThis work focuses on the influence of humic acids (HAs) on the fate of carbon nanotubes (CNTs) in aqueous media. This influence was demonstrated by mixing CNT powder with HAs in aqueous solution in varying concentrations. The aqueous media containing HAs and CNTs were size-characterized by asymmetrical flow field-flow fractionation (AsFlFFF) coupled with multi-angle light scattering (MALS). This coupling yielded information concerning the size distribution of single- and multi-walled CNTs (SWCNTs and MWCNTs) and HAs under different physico-chemical conditions that can occur in environmental water. HAs can disperse individual CNTs in aqueous media. However, the difference in the physical structure between SWCNTs and MWCNTs leads to significant differences in the quantity of HA that can adsorb onto the nanotube surface and in the stability of the CNT/HA complex. Compared with MWCNTs, SWCNTs suspended in HAs are less affected by changing ionic strength with respect to stability and the amount suspended

Multi-wall carbon nanotube aqueous dispersion monitoring by using A4F-UV-MALS

cited By 7International audienceIn this work, the potentiality of asymmetrical flow field-flow fractionation (A4F) hyphenated to UV detector and multi-angle light scattering (MALS) was investigated for accurately determining multi-walled carbon nanotube (MWCNT) length and its corresponding dispersion state in aqueous medium. Fractionation key parameters were studied to obtain a method robust enough for heterogeneous sample characterization. The main A4F conditions were 10 -5 mL min -1 NH 4NO 3, elution flow of 1 mL min -1, and cross flow of 2 mL min -1. The recovery was found to be (94∈±∈2)%. Online MALS analysis of eluted MWCNT suspension was performed to obtain length distribution. The length measurements were performed with a 4% relative standard deviation, and the length values were shown to be in accordance with expected ones. The capabilities of A4F-UV-MALS to size characterize various MWCNT samples and differentiate them according to their manufacturing process were evaluated by monitoring ball-milled MWCNT and MWCNT dispersions. The corresponding length distributions were found to be over 150-650 and 150-1,156 nm, respectively. A4F-UV-MALS was also used to evaluate MWCNT dispersion state in aqueous medium according to the surfactant concentration and sonication energy involved in the preparation of the dispersions. More especially, the presence or absence of aggregates, number and size of different populations, as well as size distributions were determined. A sodium dodecyl sulfate concentration of 15 to 30 mmol L -1 and a sonication energy ranged over 20-30 kJ allow obtaining an optimal MWCNT dispersion. It is especially valuable for studying nanomaterials and checking their manufacturing processes, size characterization being always of high importance

A new analytical approach based on asymmetrical flow field-flow fractionation coupled to ultraviolet spectrometry and light scattering detection for SWCNT aqueous dispersion studies

cited By 8International audienceThis work demonstrates the potential of asymmetrical flow field-flow fractionation (A4F) coupled to Ultraviolet spectrometry (UV) and multi-angle light scattering (MALS) for the study of single-walled carbon nanotube (SWCNT) dispersion in aqueous solutions containing a surfactant. The results indicate that this technique is a powerful analytical tool that is able to evaluate SWCNT dispersion states in aqueous media and, more importantly, determine the presence or absence of aggregates, the numbers and sizes of different SWCNT populations and the SWCNT size distribution. Dynamic light scattering was employed to complete and demonstrate the relevance of the data that were obtained via A4F-UV-MALS. Two different anionic surfactants that are used to disperse SWCNTs were then studied. The dispersing powers of the surfactants were experimentally evaluated based on their structural organizations. This study demonstrates that surfactant concentration and sonication energy are key parameters that control the SWCNT dispersion state and SWCNT structural integrity therein. © The Royal Society of Chemistry 2012

Nanoparticle characterization by cyclical electrical field-flow fractionation

cited By 13International audienceIn this work, the analytical potential of cyclical electrical field flow fractionation (CyElFFF) for nanomaterial and colloidal particle characterization has been experimentally demonstrated. Different operating parameters were investigated in order to evaluate their effect on the mechanisms of retention and fractionation power of CyElFFF. The voltage and frequency of the oscillating electrical field appeared to be the most influential parameters controlling the separation mode. Mobile phase flow rate was also found to be a key parameter controlling the fractionation efficiency. This work allowed the definition of operating conditions such that a reliable CyElFFF analysis could be performed on different nanoparticles on the basis of the direct comparison of their theoretical and experimental behavior. The results show that this technique in optimized conditions is a powerful tool for electrophoretic mobility based separation and characterization of various nanoparticles. © 2011 American Chemical Society