ポスター発表
第2日 6月11日（火） P会場（多目的ホール・大会議室101＋102）P1会場（多目的ホール）・P2会場（会議室101＋102）
- 2P-21（3C-O1-0933）
LA-ICP-MSを用いた同位体比計測におけるイオン検出器の不感時間に由来する誤差
(東大地殻化学)
o仁木創太・ 平田岳史
The lack in signal input/output linearity of ion detectors due to the counting loss during detector refresh time (i.e., dead time) is nightmare for elemental and isotopic analysis of solid materials using laser ablation ICP mass spectrometry (LA-ICP-MS). By using LA-ICP-MS, signal intensity data for analytes are acquired through integration of transient signal events emanating from individual particles generated through LA and transported into ICP. Then, the counting loss can be significant when a coarse particle is introduced into ICP.
In this study, for investigation on the counting loss of the transient signals derived from particle introduction, isotopic-ratio analysis of individual particles generated through LA is conducted by high-time-resolution multiple-collector ICP-MS coupled with an in-house micron-resolution femtosecond LA system (Tandem fsLA system). The analysed sample was brass, and, based on the Cu and Zn isotopic analysis of individual LA-generated particles, the further undercounting due to the extension of the refresh time is observed when the signal intensity exceeds 107 cps corresponding to the particle size of several tens of nanometres. This feature of the ion detectors requires the calibration of elemental and isotopic ratios based on a reference material whose concentration of analytes is similar to that for unknown samples.