Single particle ICP-MS characterization of platinum nanoparticles uptake and bioaccumulation by Lepidium sativum and Sinapis alba plants
The increasing use of platinum in different forms including engineered nanoparticles (PtNPs) in a wide range of industrial applications and in particular in automotive catalysts is leading to a rising concern about their release and fate in the environment. This study investigates for the first time the uptake and fate of PtNPs by plants. Two model organisms Lepidium sativum and Sinapis alba were exposed to 70 nm PtNPs. An enzymatic digestion method was developed in order to extract intact PtNPs from the different plant tissues, optimizing different parameters in order to obtain the highest number of nanoparticles. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) was developed to provide information about nanoparticle size, nanoparticle number concentration and the presence of dissolved platinum in the samples. The enzymatic treatment allowed the extraction of PtNPs from the different tissues without changing their oxidation or aggregation state. The presence of PtNPs at the nominal size in all tissues from both plants was observed. PtNPs with higher sizes than the nominal one were observed as well, suggesting the occurrence of an aggregation process. The presence of platinum in the dissolved form was not detected.