ISOTOPE-RATIO-MONITORING OF O2 FOR MICROANALYSIS OF 18O/16O AND 17O/16O IN GEOLOGICAL MATERIALS - STRATEGIES FOR HIGH PRECISION AND ACCURACY WITH LASER HEATING

Abstract

Experiments were performed to test the viability of using isotope-ratio-monitoring gas-chromatography mass spectrometry (irm-GCMS) as a means for isotopic analysis of nanomole quantities of O2 released in a vacuum system suitable for laser extraction and fluorination. Several sources of error were identified and eliminated, including false signals from extraneous scattered ions and adsorption of O2 to metal surfaces. Results show that with appropriate attention to these potential impediments, coupling high-precision irm-GCMS to laser sampling of microgram quantities of silicate and oxide minerals is feasible.