Isotopic analysis of platinum from single nanoparticles using a high-time resolution multiple collector Inductively Coupled Plasma - Mass Spectroscopy

Abstract

Isotopic analysis, together with size distribution analyses of platinum nanoparticles (Pt NPs) have been made by a multiple collector-ICP-mass spectrometer equipped with a high-time resolution data acquisition system (HTR-MC-ICP-MS). With the present system, time-integration efficiency of nearly 100% was achieved from up to four isotopic signals, enabling us to measure both the size and isotopic ratios from a single NP. Based on the 195Pt/194Pt ratios obtained from more than 1000 particles, the precisions of the 195Pt/194Pt ratio measurements on 30 nm, 50 nm, and 70 nm were approximately 40% (2SD), 20% (2SD), and 10% (2SD). These results were comparable to possible variations in the 195Pt/194Pt ratios estimated by counting statistics of the isotopic signals, suggesting that the isotopic ratio measurements could be achieved from transient signal events originating from NPs. The data obtained here demonstrated that the HTR-MC-ICP-MS technique can become a powerful tool to monitor the elemental/isotopic ratios from single NPs.