Radiocarbon analysis

Haynes, C. V., Radiocarbon Analysis of Inorganic Carbon of Fossil Bone and Enamel, Science, 1968, 161, 687-688. 

ASTM International (2007) ASTM D6866-08 Standard test methods for determining the biobased content of solid, liquid, and gaseous samples using radiocarbon analysis. ASTM International, West Conshohocken... 

In this appendix, we briefly describe sample preparation and radiocarbon analysis, as well as the conventions for reporting of 14C data. We have tried to strike a balance between brevity and explanation, addressing common questions we have encountered. Additionally, we urge those interested in using 14C data to read Stuiver and Polach (1977), the paper that established most 14C reporting conventions and from which most of the equations in this appendix were acquired. 

Radiocarbon analysis is possible for dating ancient textiles only where sufficient sample is available. Unfortunately, the uncertainty in dating becomes unacceptably large with small sample size, contamination, and specimens of lesser antiquity (5). Chemical methods of dating are mainly limited to the observation that reducing the sulfur content of wool textiles appears to coincide, in some cases, with embrittlement and/or age (6). The presence of certain kinds of dyes and the manner in which they fade are sometimes used as the evidence of provenance (7). 

Radiocarbon Dating of Amino Acids Extracted from Chione Shell. We attempted to resolve the question of which dating method produced more accurate shell dates by submitting amino acids extracted from Chione shell for a radiocarbon analysis (20). Because of the possibility of exchange with groundwater carbonates, the inorganic carbon in mollusc shell can be contaminated easily. We reasoned that the carbon in the amino acids would provide a more reliable age estimate than the carbon-... 

Repeta, D. J., and Aluwihare, L. I. (2006). Radiocarbon analysis of neutral sugars in high molecular weight dissolved organic matter implications for carbon cycling. Limnology and Oceanography 51(2), 1045-1053. 

Rowe, M.W. (2000) Dating by AMS radiocarbon analysis. In Whitley, D.S. (Eds) Handbook of Rock Art Research. Walnut Creek Altamira Press, pp. 139-166. 

Stratified samples are also amenable to radiocarbon analysis and can potentially provide better average turnover times for particular climatic/soil-texture conditions than site-specific studies, using any of the available methodologies (e.g.. Bird et al, 1996 Trumbore, 1993 Harrison et al, 1995). C results for the 63- to 500-jum fraction for the stratified Canadian samples discussed above are provided in Fig. 8. Again, the apparent turnover times for carbon in this size fraction increases with decreasing temperature and precipitation in keeping with expectations based on discussion in preceding sections. 

As one example of the application of single-compound radiocarbon analysis, we show a detailed data set for a range of lipid biomarkers extracted from marine... 

Pearson A (2000) Biogeochemical Applications of Compound-Specific Radiocarbon Analysis. PhD thesis, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution. 

Pathways of carbon flow in natural environments have also been reconstracted using bulk stable carbon and nitrogen isotopes as well as compound-specific isotopic analysis of individual biomarker lipid component (Hayes et al, 1990) based on the fractionations involved during primary (photosynthetic) and secondary (heterotrophic) processes. Recently, compound-specific radiocarbon analysis of individual biomarker hpid has been shown to be a valuable technique to determine the source of marine organic matter (Eglinton et al., 1997). 

Voorhees et al. ° reported a study of the insoluble carbonaceous material in airborne particulates from vehicular traffic using Py-MS and Py-GC/MS (in addition to TGA, elemental analysis, and radiocarbon analysis). The solvent-soluble organic compounds separated from atmospheric particulate matter (which encompasses a broad spectrum of solid and liquid particles generally ranging in size from several hundred angstroms to several hundred micrometers) had been extensively studied by numerous investigators. Due to its complexity, the insoluble carbonaceous material (ICM) in urban and rural particulate material had not been studied in depth. 

American Standard Test Method (ASTM) D6866 - 11 Standard Test Methods for Determining the Biobased Content of Sohd, Liquid, and Gaseous Samples Using Radiocarbon Analysis, http //www.astm. org/DATABASE.CART/HISTORICAL/D6866-l l.htm (accessed 22 August 2013). 

Figure 14.6 Measurement of bio-based carbon content using radiocarbon analysis (ASTM D6866). (Reproduced with permission from ref. HI. Copyright 2012, American Chemical Society.)...

The principle of isotopic age determination is used in food analysis. Radiocarbon analysis can be used to detect whether a product is of natural or synthetic origin. The absence of in the sample would indicate a synthetic origin, while the presence of indicates a natural origin. The determination of tritium contents can be used, e.g., to determine the age of wine. 

Next, low-temperature (<150°C), low-pressure torr) oxygen plasmas oxidized organic components of the sample to CO2. Decomposition of inorganic carbon present (dolomitic limestone rock and calcite/calcium oxalate accretions) was prevented by running the plasmas at low-temperature. Carbon dioxide from the sample was flame-sealed into a glass tube cooled to liquid nitrogen temperature (-194°C), after water had been frozen out with a dry-ice/ethanol slurry (-58°C), and finally sent for radiocarbon analysis at the Center for Accelerator Mass Spectrometry at the Lawrence Livermore National Laboratory (LLNL-CAMS). It was necessary to utilize an AMS measurement due to the small sample size. 

The biobased content of the plastic material can be established by tests that measure carbon isotopes of the polymer material. In the United States, the ASTM D6866 standard estabUshes the procedures, equipment, materials, and conditions to measure the 14C content of the plastic sample through radiocarbon analysis. ASTM D6866 biobased standard establishes that a material can be certified as biobased if greater than 99% of the carbon in the plastic sample is made from organic sources and is characterized by a 14C isotope. This will be further explained in Chapter 8. 

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