Development of a novel method to detect a potential inhalation of nanoaerosols

In the context of the precautionary principle for engineered nanoparticles, a test able to verify the non exposure of individuals to nanoaerosols seems to be of great interest, especially for workers involved with nanomaterials. A novel method is proposed to detect the presence of nanoparticles in the nose. Different materials, including paper and polycarbonate, have been tested for their sampling efficiency towards ZnO nanoparticles. The detection of nanoparticles is performed by elemental analysis using Total Reflection X-Ray Fluorescence (TXRF). For an optimal sensitivity of the TXRF signal, samples have to be deposited on a smooth surface. Therefore, different materials have been compared as sample carrier. The results indicate that pure paper is the most efficient material for sampling nanoparticles (ZnO), while the use of polycarbonate, and even more flexible polyester, as sample carrier allows a better sensitivity for TXRF analysis. Therefore, the sampling device made of paper is digested under slightly acidic conditions in a microwave oven after collection, and the resulting solution is deposited on polyester for TXRF analysis. Internal calibration is performed thanks to an addition of Rb to the samples. The proposed method allows the chemical identification of nanoparticles deposited in the nose: a qualitative signature of a potential nanoaerosol inhalation.