A Continuous-Flow Gas Chromatography ¹⁴C Accelerator Mass Spectrometry System

Abstract

ABSTRACT. Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO 2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14 C AMS system fitted with a microwave ion source for real-time compoundspecific 14 C analysis. As an initial test of the system, we have analyzed a sample of fatty acid methyl esters and biodiesel. Peak shape and memory was better then existing systems fitted with a hybrid ion source while precision was comparable. 14 C/ 12 C ratios of individual components at natural abundance levels were consistent with those determined by conventional methods. Continuing refinements to the ion source are expected to improve the performance and scope of the instrument.

A gas-accepting ion source for Accelerator Mass Spectrometry: Progress and applications

“…The open split was also fitted with an additional capillary that could be actuated in/out of the gas stream to supply reference CO 2 to the ion source for normalization purposes. Further details of the setup and some initial test results can be found elsewhere [6,7] .…”

Improved Precision of Radiocarbon Measurements for CH4 and CO2 Using GC and Continuous-Flow AMS Achieved by Summation of Repeated Injections

“…Gas chromatographs have been interfaced to AMS systems with both hybrid-sputter and microwave-plasma type sources (Bronk Ramsey et al 2004;Flarakos et al 2008;McIntyre et al 2010). The basic on-line setup follows that of stable isotope ratio mass spectrometry, in which the gas stream from the GC is passed through a combustion furnace to convert the separated compounds to CO 2 (Merritt et al 1995).…”

Rapid radiocarbon (14C) analysis of coral and carbonate samples using a continuous‐flow accelerator mass spectrometry (CFAMS) system

“…However, the source requires a higher flow rate of gas and is less efficient than a hybrid source and thus, is ill‐ suited to small samples or high precision measurements. Nonetheless, direct acceptance of a continuous flowing stream of CO 2 has allowed analytical instruments such as a gas chromatograph to be interfaced directly to the CFAMS system for rapid and compound specific radiocarbon analyses [ McIntyre et al , 2009; McIntyre et al , 2010].…”