レーザー質量分析計を用いたナノ粒子・溶存成分の同時イメージング分析

抄録

The ICP-mass spectrometry (ICP-MS) is a sensitive and rapid analytical tool for trace-elements in various materials. The ICP-MS technique is now applied to measure both the sizes and number concentrations of nanoparticles (NPs), mainly dispersed in the aqueous solutions. Another important feature of the ICP-MS is the analytical capability for the imaging analysis using a laser ablation sampling technique. Imaging analysis was conducted based on the repeated-line profiling analyses, and the resulting time-dependent signal intensity profiles were converted to the position-dependent signal intensity data using the in house “iQuantNP” software. With the technique developed here, signal intensities for small size fraction (<10 nm) were also visualized. More importantly, chemical status of the analytes, whether present as particulates or as dissolved (ionic) forms, can also be derived by the present technique (Triad Imaging : size, position, and chemical status of analytes). The Triad Imaging technique can provide key information to understand the transport, interaction, and decomposition/dissolution features of the metal NPs.

The major drawback of the current ICP-MS system for the detection of NPs is that only single element (isotope) can be monitored, and thus, no elemental and isotopic ratio data can be made from individual NPs. Faced with this, we are currently developing new ion detection technique for the ICP-MS designed for elemental and isotopic analyses on multiple component NPs. The sensitive and rapid imaging technique for the NPs has immediate potential as a reconnaissance method and given increasing improvement in instrumentation will in the future produce benchmark data for the NPs toxicology.