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