tracing isotope造句

Our current knowledge of the mechanism of oxygen evolution during photosynthesis was further established in experiments tracing isotopes of oxygen from water to oxygen gas.
Dansgaard was the first paleoclimatologist to demonstrate that measurements of the trace isotopes oxygen-18 and deuterium in accumulated glacier ice could be used as an indicator of past climate.
It's difficult to find tracing isotope in a sentence. 用tracing isotope造句挺难的