Gas chromatographic isolation of individual compounds from complex matrices for radiocarbon dating
- Woods Hole Oceanographic Inst., MA (United States)
- College of Wiliam and Mary, Gloucester Point, VA (United States)
- Univ. of California, Irvine, CA (United States)
This paper describes the application of a novel, practical approach for isolation of individual compounds from complex organic matrices for natural abundance radiocarbon measurement. This is achieved through the use of automated pereparative capillary gas chromatography (PCGC) to separate and recover sufficient quantities of individual target compounds for {sup 14}C analysis by accelerator mass spectrometry (AMS). We developed and tested this approach using a suite of samples (plant lipids, petroleums) whose ages spanned the {sup 14}C time scale and which contained a variety of compound types (fatty acids, sterols, hydrocarbons). Comparison of individual compound and bulk radiocarbon signatures for the isotopically homogeneous samples studied revealed that {Delta}{sup 14}C values generally agreed well ({+-}10%). Background contamination was assessed at each stage of the isolation procedure, and incomplete solvent removal prior to combustion was the only significant source of additional carbon. Isotope fractionation was addressed through compound-specific stable carbon isotopic analyses. Fractionation of isotopes during isolation of individual compounds was minimal (<5% for {delta}{sup 13}C), provided the entire peak was collected during PCGC. Trapping of partially coeluting peaks did cause errors, and these results highlight the importance of conducting stable carbon isotopic measurements of each trapped compound in concert with AMS for reliable radiocarbon measurements. 29 refs., 9 figs., 2 tabs.
- DOE Contract Number:
- FG02-92ER61428
- OSTI ID:
- 232399
- Journal Information:
- Analytical Chemistry (Washington), Vol. 68, Issue 5; Other Information: PBD: 1 Mar 1996
- Country of Publication:
- United States
- Language:
- English
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