Laser Ablation Multi Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) is an analytical technique that can obtain isotopic information directly from solid phases, thus preserving spatial context; typically sampling a volume ~10-100 µm in diameter and >1 µm in depth. This technique is particularly useful for making spatially resolved measurements of (1) stable and radiogenic isotope ratios for fingerprinting different geologic sources and processes and (2) radiogenic isotope ratios for geochronology. A pulsed focused laser beam removes material from the sample, with the resulting aerosol being transported into the Multi Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS) for ionization and detection.

LA-MC-ICP-MS analyses are performed using an Applied Spectra J200 femtosecond laser source that is configured with a tandem Laser Ionization Breakdown Spectroscopy (LIBS) system. A custom laser chamber enables simultaneous LA-MC-ICP-MS and LIBS analyses. This state-of-the-art laser ablation system provides a significant improvement related to the physical ablation process of geological phases, allowing for more accurate isotopic analyses in an expanded range of astromaterials. In particular, the <500 fs pulse length of the laser produces little or no element fractionation at the sample surface; a difficulty for nanosecond pulsed lasers. The femtosecond laser also offers a significantly reduced ablation volume for analysis when compared to excimer lasers, allowing for improved spatial resolution. The laser is primarily coupled to the new Nu 1700 Sapphire MC-ICP-MS for analysis of various stable isotope systems (Mg, Si, Ca, etc.) and radiogenic isotope systems (Ca, Sr, Pb, etc.) in astromaterials and their Earth analogs.

Center for Isotope Cosmochemistry and Geochronology (CICG)

Center for Isotope Cosmochemistry and Geochronology (CICG)

LA/LIBS MC-ICP-MS: NASA scientist Jake Setera adjusts the Applied Spectra femtosecond laser system.