Isotope dilution mass spectrometry (IDMS) with mixing a target sample and a isotopic standard differed from natural abundance is often used for analysis of trace elements and isotopes in biological and environmental samples. This method is a highly sensitive and accurate analytical technique, but conventional IDMS cannot provide distribution information on the solid sample surface because the sample and the standard has to be mixed uniformity through process of such grinding and dissolvation. Therefore, we developed a quantitative imaging method of trace components by combining a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) that which enables highly sensitive imaging and an originally-designed chamber to mix the sample aerosol by a LA and a sprayed isotopic standard in the gas phase (Fig. 1).
 Proposed method determines the distribution of elemental concentrations from estimation of supplied amount of each isotope from the target sample through sequential mixing and measuring the aerosol containing isotopic standards with different isotopic ratios and known concentration, if the isotopic ratio and the amounts of the solid sample drilled by a LA could be provided. The isotopic ratio and the drilled amounts of the samples were determined by a LA (without mixing isotopic standard) and a digital microscope, respectively. As a result, both quantification and imaging of trace elements on the solid samples such as human teeth were achieved (Fig. 2).
 The proposed method is promising for analyzing trace elements and RIs in a variety of biological and environmental samples.

This work was supported by JAEA Nuclear Energy Science & Technology and Human Resource Development Project Grant Number JPJA19H19210081, "Development of Methodology Combining Chemical Analysis Technology with Informatics Technology to Understand Perspectives Property of Debris and Tie-Up Style Human Resource Development."