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Automated system for simultaneous analysis of δ 13 C, δ 18 O and CO 2 concentrations in small air samples
Author(s) -
RibasCarbo Miquel,
Still Chris,
Berry Joe
Publication year - 2002
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.582
Subject(s) - chemistry , replicate , analytical chemistry (journal) , inlet , mass spectrometry , chromatography , isotope , nuclear physics , statistics , physics , mathematics , engineering , mechanical engineering
In this paper we present an automated system for simultaneous measurement of CO 2 concentration, δ 13 C and δ 18 O from small (<1 mL) air samples in a short period of time (≈1 hour). This system combines continuous‐flow isotope ratio mass spectrometry (CF‐IRMS) and gas chromatography (GC) with an inlet system similar to conventional dual‐inlet methods permitting several measurement cycles of standard and sample air. Analogous to the dual‐inlet method, the precision of this system increases with the number of replicate cycles measured. The standard error of the mean for a measurement with this system is 0.7 ppm for the CO 2 concentration and 0.05‰ for the δ 13 C and δ 18 O with four replicate cycles and 0.4 ppm and 0.03‰ respectively with nine replicate cycles. The mean offset of our measurements from NOAA/CMDL analyzed air samples was 0.08 ppm for the CO 2 concentration, 0.01‰ for δ 13 C and 0.00‰ for δ 18 O. A specific list of the parts and operation of the system is detailed as well as some of the applications for micrometeorological and ecophysiological applications. Copyright © 2002 John Wiley & Sons, Ltd.