Improved techniques for stable isotope analyses of microlitre quantities of water from fluid inclusions in halite and concentrated brines

A method has been developed to analyze both H- and 0-isotope compositions of saline waters and fluid inclusion brines without significant interference of salts. It involves high-temperature distillation under vacuum and reaction of the extracted water with zinc to produce HZ for H-isotope analyses and with guanidine hydrochloride (GuHCI) to produce CO2 for O-isotope analyses. prec:isions of ± 2%o and ±0.3%o for 8D- and 8ʹ $O-values, respectively, can be realized with as little as 4 μ1 saline water for bath elements.