A new analytical coupling method based on direct coupling of nano-flow separation technique (capillary electrophoresis, nanoLC, LC on chip) to the mass or optical spectrometry (ICPMS or ICPOES). This new device is dedicated to the 2D characterization of nanoparticles in suspension. It will be realized via a ?drop on demand? piezo electrical interface. It will allow separating nanoparticles according to their physic ?chemical properties acquiring quantitative information on their size and chemical composition. This subject involves instrumentation, physic-chemistry and analytical chemistry skills. It can be divided in: instrumental settings, a fundamental study on mono-disperse droplet generation (size, velocity, evaporation, ) and finally an analytical study on nanoparticles separation. It is proposed by the Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (DSM/IRAMIS/SIS2M/LIONS) specialized on nanoparticles suspension fondamental study in cooperation with the Laboratoire D'Ingénierie des Surfaces et des Lasers du Service des Etudes Analytiques et de réactivité des Surfaces (DEN/DANS/DPC/SEARS/LISL) for instrumentation. A third laboratory, the Laboratoire d'Expérimentation en Confinement, Epuration et Ventilation (IRSN/DSU/SERAC/LECEV) will participate to the project for its expertise in droplet methrology.