Gas stable isotopic ratio mass spectrometry for measuring δ13C and δ18O in background atmospheric CO2
气体稳定同位素比质谱法分析本底大气CO2的δ13C和δ18O

A high precision gas stable isotopic ratio mass spectrometry system was set up to measure CO2 stable isotopes in background air samples.The system consisted of a MAT253 isotopic ratio mass spectrometry,an efficient airtrap extraction line and a custom designed auto sampler.In combination with periodic target injection,two working standards were injected before and after each of the unknown sample to control and monitor the system performance.The working standards were calibrated regularly to trace back higher level reference and to ensure measurement comparability.From repeated test,the system precision was better than 0.03‰ and 0.06‰ for δ13C and δ18O,respectively.The system could apply to the δ13C and δ18O analysis in background atmospheric CO2 and essentially meet the WMO/GAW quality target.