@article {577,
	title = {Radiocarbon dating of diatom-bound organic compounds},
	journal = {Marine Chemistry},
	volume = {92},
	year = {2004},
	note = {882iaTimes Cited:34Cited References Count:33},
	month = {Dec 1},
	pages = {91-105},
	abstract = {Here we present a new method for obtaining radiocarbon dates for the organic compounds intrinsic to diatom frustules. This method will improve age models for sediment cores that lack calcium carbonate and improve current interpretations of diatom-based paleoproxies. In preparation for radiocarbon dating by Accelerator Mass Spectrometry, compounds intrinsic to diatom frustules are released from their opal matrix by dissolution in HF and then purified using preparative liquid chromatography-mass spectrometry (LC-MS). The method was applied to one sample from each of three cores (NBP9802 Station 7 GC2; TN057-13 PC4; Ell-2) and a plankton tow (CRS 746, FOODBANCS) collected in the Southern Ocean. In each sample, radiocarbon ages of diatom-bound organic compounds differed from those obtained from foraminiferal CaCO3. Agreement between the foraminifera and compound-specific date was best in cores Ell-2 and TN057-13. In contrast, compound-specific C-14 ages obtained from NBP9802 differed substantially from those measured for foraminiferal CaCO3. The influence of background contamination was assessed throughout all stages of the method and cannot be responsible for the discrepancy observed. Possible reasons for the disagreement between the ages of foraminifera and diatom-bound compounds are discussed in the context of sediment dynamics. These preliminary results suggest that our diatom-based dating method represents a major step forward in our ability interpret sediment records in the Southern Ocean and therefore our understanding of the role of the Southern Ocean in past climate. (C) 2004 Elsevier B.V. All rights reserved.},
	issn = {0304-4203},
	doi = {10.1016/j.marchem.2004.06.019},
	author = {Ingalls, A. E. and Anderson, R. F. and Pearson, A.}
}
@article {637,
	title = {Radiocarbon as a tool to apportion the sources of polycyclic aromatic hydrocarbons and black carbon in environmental samples},
	journal = {Environmental Science \& Technology},
	volume = {36},
	year = {2002},
	note = {541gfTimes Cited:133Cited References Count:59},
	month = {Apr 15},
	pages = {1774-1782},
	abstract = {To determine the relative inputs of polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) in environmental samples from the combustion of fossil fuels and biomass we have developed two independent analytical methods for determining the C-14 abundance of PAHs and BC. The 5730 yr half-life of C-14 makes it an ideal tracer for identifying combustion products derived from fossil fuels (C-14-free) versus those stemming from modern biomass (contemporary C-14). The C-14 abundance of PAHs in several environmental Standard Reference Materials was measured by accelerator mass spectrometry after extraction and then purification by high-performance liquid chromatography and preparative capillary gas chromatography. This method yields pure compounds that allow for a high degree of confidence in the C-14 results. The PAHs data were then used to compare and evaluate results from an operationally defined thermal oxidation method used to isolate a BC fraction. The C-14 compositions of PAHs and BC were very similar and suggest that the thermal oxidation method employed for isolating BC is robust and free from interferences by non-BC components. In addition, these data indicate that both the PAHs and the BC species derive mostly from fossil fuels and/or their combustion products.},
	issn = {0013-936x},
	doi = {10.1021/es011343f},
	author = {Reddy, C. M. and Pearson, A. and Xu, L. and McNichol, A. P. and Benner, B. A. and Wise, S. A. and Klouda, G. A. and Currie, L. A. and Eglinton, T. I.}
}
