Symposium Sessions
Day 1, June 10（Wed.） 15:48-16:06 Room A (5F 503)
- 1A-S2-1548
Development of LA-MICAL-CF-IRMS system for carbonate δ13C and δ18O ultra-microanalysis
(1Shinshu Univ., 2Kyoto Univ.)
oAkimasa Suzumura1, Hisashi Asanuma2, Toyoho Ishimura2
δ13C and δ18O in carbonates are fundamental tracers for the paleoenvironment and paleoclimatology. The microgram-scale calcite auto-measurement line (MICAL) -CF-IRMS system enables high-precision analysis using sample amounts approximately 100 times smaller (~0.1 µg) than a conventional method. However, this system introduces samples as CO2 gas generated by reacting phosphoric acid with carbonate powders collected by drilling, which struggles to achieve both high spatial resolution and high recovery simultaneously. In this study, we aimed to develop a hybrid analytical system integrating the MICAL-IRMS with laser ablation (LA) as an alternative micro-sampling technique.
While LA method offers high spatial resolution for solid micro-sampling, a conventional system is typically designed for atmospheric pressure sampling. We developed a vacuum-tight ablation cell and a gas collection system for vacuum-based sample introduction into the MICAL system. The analytical precision for both δ13C and δ18O reached 0.2‰ or better. Notably, although offsets from reference values were observed (~1.5‰ for δ13C and ~1‰ for δ18O), they exhibited a consistent linear relationship with the reference values across all samples, suggesting that high accuracy is achievable by standard calibration curves. This newly developed method enables in-situ isotopic analysis of carbonates with high precision, accuracy, and sensitivity.