Elemental and isotope ratio analysis of single nanoparticles using a multiple collector ICP-MS

Abstract

Elemental and isotopic ratio analyses, together with size distribution analyses, have been made from single Pt-and Pt-Au nanoparticles using a multiple collector ICP-mass spectrometer equipped with a high-time resolution data integration system. With the present system set-up, high-speed data integration (up to 100000 Hz) with nearly 100 % time-integration efficiencies can be achieved from up to 4 high-gain ion collectors, enabling us to measure elemental and isotopic ratio analyses from single nanoparticles. The measured 195 Pt/ 194 Pt ratio from Pt NPs of two sizes (30 nm and 50 nm) showed that the repeatability of the isotope ratio measurements was mainly controlled by the counting statistics of the signal, suggesting that effective data acquisition could be achieved under transient signals produced from the NPs. The analytical capability of the system was evaluated by monitoring the Au/Pt ratio from multi-component NPs produced through the laser ablation in liquid (LAL) technique. The MC ICP-MS analysis for the Pt-Au NPs revealed that both the size and Au/Pt ratio of the NPs varied significantly by reflecting the laser ablation conditions. Possible mechanisms for the variations in the sizes and Au/Pt ratios of the Pt-Au NPs produced by the LAL technique will be discussed in this study.