Identification of TiO2 nanoparticles using La and Ce as labels: application to the evaluation of surface contamination during the handling of nanosized matter

Abstract

Distinguishing nanomaterials of interest from background nanosized matter already present in the sampling environment is a challenging task. In this study, we propose the use of rare earth elements (REEs) as high-sensitivity labels to identify and to monitor their fate following manipulation. The REE labels were added during the synthesis of TiO₂ nanoparticles with hydrodynamic sizes of 15 nm. The REE-labelled nanomaterials allow the monitoring of nanoparticle aerosols formed during handling of nanoparticulate materials in a glove box. The deposition of the labelled TiO₂ nanoparticles on working surfaces could be verified by electron microscopy and surface analysis, using the presence of lanthanide elements as an identification label. The total amount of TiO₂ nanoparticles in the deposited material could be quantified by a procedure based on wiping the deposition area followed by digestion of the collected matter and analysis by flame emission spectrometry.