An analytical system for stable isotope analysis on carbon monoxide using continuous-flow isotope-ratio mass spectrometry

S. L. Pathirana, C. van der Veen, M. E. Popa, T. Röckmann
2015 Atmospheric Measurement Techniques  
<p><strong>Abstract.</strong> A fully automated system for the determination of δ<sup>13</sup>C and δ<sup>18</sup>O in atmospheric CO has been developed. CO is extracted from an air sample and converted into carbon dioxide (CO<sub>2</sub>) using the Schütze reagent. The isotopic composition is determined with an isotope-ratio mass spectrometer (IRMS) technique. The entire system is continuously flushed with high-purity helium (He), the carrier gas. The blank signal of the Schütze reagent is ~ 4
more » ... ütze reagent is ~ 4 nmol mol<sup>−1</sup>, or 1–3 % of the typical sample size. The repeatability is 0.1 &amp;permil; for δ<sup>13</sup>C and 0.2 &amp;permil; for δ<sup>18</sup>O. The peak area allows for simultaneous determination of the mole fraction with an analytical repeatability of ~ 0.7 nmol mol<sup>−1</sup> for 100 mL of ambient air (185.4 nmol mol<sup>−1</sup> of CO). An automated single measurement is performed in only 18 min, and the achieved time efficiency (and small volume of sample air) allows for repetitive measurements practically.</p>
doi:10.5194/amt-8-5315-2015 fatcat:3kwf2vx3mndatgs3sdabwexfpe