微量水δ(17O)和δ(18O)CoF3法线外同时测试新技术
摘要
Tri-oxygen isotopes (16O, 17O, 18O) composition in water is a very effective tool to trace the origin and formation environment of water, and tri-oxygen isotopic studies have become a hot and fore front topic with the development of mass-independent isotopic fractionation. This study has set up a new technique for the determination of 18O/16O and 17O/16O isotopic ratios in water from small liquid sample for the first time in China. The new technique will enlarge isotopic research field, such as quantitative determination of oxygen isotopic fractionation in the biological process of photosynthesis and respiration. The meth od of water fluorination is optimized by using the solid reagent CoF3 to produce O2. This allows the isotope ratio measurements by dual-inlet mass spectrometry with very high precision of ±0.07‰ and 0.14‰ for bothδ17O andδ18O with water sample of only 2μL. The fluorination step takes less than 20 min, while the total processing time of each sample is about 40 min. The method does not use the fluorination reagent BrF5 employed in traditional methods. It is hence safer, cheaper and more reliable than traditional means and accords with the environmental awareness arid the people-oriented principle.