Improved precision of radiocarbon measurements for Ch4 and Co2 using GC and continuous-flow AMS achieved by summation of repeated injections

Mcintyre, C. P. , McNichol, A. P., Roberts, M. L., Seewald, J. S., von Reden, K. F. and Jenkins, W. J. (2013) Improved precision of radiocarbon measurements for Ch4 and Co2 using GC and continuous-flow AMS achieved by summation of repeated injections. Radiocarbon, 55(2-3), 677- 685.

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Abstract

Compound specific radiocarbon measurements can be made instantaneously using a gas chromatograph (GC) combustion system coupled to a 14C AMS system fitted with a gas ion source. Samples below 10 µg C can be analyzed but the precision is reduced to 5–10% because of lower source efficiency. We modified our GC for CH4 and CO2 analysis and injected samples multiple times to sum data and increase precision. We attained a maximum precision of 0.6% for modern CO2 from 25 injections of 27 µg C and a background of ~0.5% (40 kyr) for ancient methane. The 14C content of dissolved CO2 and CH4 in water samples collected at a deep-sea hydrothermal vent and a serpentine mud volcano was measured and the results for the vent sample are consistent with previously published data. Further experiments are required to determine a calibration and correction procedure to maximize accuracy.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mcintyre, Dr Cameron
Authors: Mcintyre, C. P., McNichol, A. P., Roberts, M. L., Seewald, J. S., von Reden, K. F., and Jenkins, W. J.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Radiocarbon
Publisher:University of Arizona
ISSN:0033-8222
ISSN (Online):1945-5755

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