A new CF-IRMS system for quantifying stable isotopes of carbon monoxide from ice cores and small air samples

• Published in: Atmospheric Measurement Techniques
• Main Authors: Z. Wang, J. E. Mak
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2010
• Subjects: Environmental engineering; TA170-171; Earthwork. Foundations; TA715-787; South Pole; ice core; South pole
• Online Access: https://doi.org/10.5194/amt-3-1307-2010; https://doaj.org/article/72eec95f772c47389f47b3e6fc3850ce

We present a new analysis technique for stable isotope ratios (δ 13 C and δ 18 O) of atmospheric carbon monoxide (CO) from ice core samples. The technique is an online cryogenic vacuum extraction followed by continuous-flow isotope ratio mass spectrometry (CF-IRMS); it can also be used with small air samples. The CO extraction system includes two multi-loop cryogenic cleanup traps, a chemical oxidant for oxidation to CO 2 , a cryogenic collection trap, a cryofocusing unit, gas chromatography purification, and subsequent injection into a Finnigan Delta Plus IRMS. Analytical precision of 0.2‰ (±1δ) for δ 13 C and 0.6‰ (±1δ) for δ 18 O can be obtained for 100 mL (STP) air samples with CO mixing ratios ranging from 60 ppbv to 140 ppbv (~268–625 pmol CO). Six South Pole ice core samples from depths ranging from 133 m to 177 m were processed for CO isotope analysis after wet extraction. To our knowledge, this is the first measurement of stable isotopes of CO in ice core air.