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Blank Assessment for Ultra-Small Radiocarbon Samples: Chemical Extraction and Separation Versus AMS

Published online by Cambridge University Press:  18 July 2016

Guaciara M Santos ,
John R Southon ,
Nicholas J Drenzek ,
Lori A Ziolkowski ,
Ellen Druffel ,
Xiaomei Xu ,
Dachun Zhang ,
Susan Trumbore ,
Timothy I Eglinton  and
Konrad A Hughen
Guaciara M Santos*
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
John R Southon
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Nicholas J Drenzek
Affiliation:
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
Lori A Ziolkowski
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Ellen Druffel
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Xiaomei Xu
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Dachun Zhang
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Susan Trumbore
Affiliation:
KCCAMS Facility, Earth System Science Department, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA Max-Planck Institute for Biogeochemistry, Jena D-07745, Germany
Timothy I Eglinton
Affiliation:
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
Konrad A Hughen
Affiliation:
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
*
Corresponding author. Email: gdossant@uci.edu
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Abstract

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The Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI) has developed protocols for analyzing radiocarbon in samples as small as ∼0.001 mg of carbon (C). Mass-balance background corrections for modern and 14C-dead carbon contamination (MC and DC, respectively) can be assessed by measuring 14C-free and modern standards, respectively, using the same sample processing techniques that are applied to unknown samples. This approach can be validated by measuring secondary standards of similar size and 14C composition to the unknown samples. Ordinary sample processing (such as ABA or leaching pretreatment, combustion/graphitization, and handling) introduces MC contamination of ∼0.6 ± 0.3 μg C, while DC is ∼0.3 ± 0.15 μg C. Today, the laboratory routinely analyzes graphite samples as small as 0.015 mg C for external submissions and ≅0.001 mg C for internal research activities with a precision of ∼1% for ∼0.010 mg C. However, when analyzing ultra-small samples isolated by a series of complex chemical and chromatographic methods (such as individual compounds), integrated procedural blanks may be far larger and more variable than those associated with combustion/graphitization alone. In some instances, the mass ratio of these blanks to the compounds of interest may be so high that the reported 14C results are meaningless. Thus, the abundance and variability of both MC and DC contamination encountered during ultra-small sample analysis must be carefully and thoroughly evaluated. Four case studies are presented to illustrate how extraction chemistry blanks are determined.

Type
Sample Preparation
Information
Radiocarbon , Volume 52 , Issue 3: 20th Int. Radiocarbon Conference Proceedings , 2010 , pp. 1322 - 1335
Copyright
Copyright © 2010 by the Arizona Board of Regents on behalf of the University of Arizona 

References

Beaupré, SR, Druffel, ERM, Griffin, S. 2007. A low-blank photochemical extraction system for concentration and isotopic analyses of marine dissolved organic carbon. Limnology and Oceanography 5:174–84.Google Scholar
Beverly, RK, Beaumont, W, Tauz, D, Patel, S, Ormsby, KM, von Reden, K, Santos, GM, Southon, JR. 2010. The Keck Carbon Cycle AMS Laboratory, University of California, Irvine: status report. Radiocarbon 52(2–3):301–9.Google Scholar
Brown, TA, Southon, JR. 1997. Corrections for contamination background in AMS 14C measurements. Nuclear Instruments and Methods in Physics Research B 123(1–4):208–13.CrossRefGoogle Scholar
Drenzek, NJ, Hughen, KA, Montluçon, DB, Southon, JR, dos Santos, GM, Druffel, ERM, Giosan, L, Eglinton, TI. 2009. A new look at old carbon in active margin sediments. Geology 37(3):239–42.Google Scholar
Druffel, ERM, Zhang, D, Xiaomei Xu, X, Ziolkowski, LA, Southon, JR, Santos, GM, Trumbore, SE. 2010. Compound-specific radiocarbon analyses of phospholipid fatty acids and n-alkanes in ocean sediments. Radiocarbon 52(2–3):1215–23.CrossRefGoogle Scholar
Eglinton, TI, Aluwihare, LI, Bauer, JE, Druffel, ERM, McNichol, AP. 1996. Gas chromatographic isolation of individual compounds from complex matrices for radiocarbon dating. Analytical Chemistry 68(5):904–12.CrossRefGoogle ScholarPubMed
Hwang, J, Druffel, E, Komada, T. 2005. Transport of organic carbon from the California coast to the slope region: a study of Δ14C and Δ13C signatures of organic compound classes. Global Biogeochemical Cycles 19: GB2018, doi:10.1029/2004GB002422.CrossRefGoogle Scholar
Ingalls, AE, Pearson, A. 2005. Ten years of compound specific radiocarbon analysis. Oceanography 18(3):18–31.CrossRefGoogle Scholar
Ingalls, AE, Shah, SR, Hansman, RL, Aluwihare, LI, Santos, GM, Druffel, ERM, Pearson, A. 2006. Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon. Proceedings of the National Academy of Sciences of the USA 103(17:6442–7.Google Scholar
Kirner, DL, Taylor, RE, Southon, JR. 1995. Reduction in backgrounds of microsamples for AMS 14C dating. Radiocarbon 37(2):697–704.Google Scholar
Kramer, C, Trumbore, S, Fröberg, M, Cisneros Dozal, LM, Zhang, D, Xu, X, Santos, GM, Hanson, PJ. 2010. Recent (<4 year old) leaf litter is not a major source of microbial carbon in a temperate forest mineral soil. Soil Biology and Biochemistry Journal 42(7):1028–37.Google Scholar
Middleton, R, Juenemann, D, Klein, J. 1994. Isotopic fractionation of negative ions produced by Cs sputtering in a high-intensity source. Nuclear Instruments and Methods in Physics Research B 93(1):39–51.Google Scholar
Muller, RA. 1977. Radioisotope dating with a cyclotron. Science 196(4289):489–94.CrossRefGoogle ScholarPubMed
Nelson, DE, Korteling, RG, Stott, WR. 1977. Carbon-14: direct detection at natural concentrations. Science 198(4316):507–8.Google Scholar
Olsson, IU. 2009. Radiocarbon dating history: early days, questions, and problems met. Radiocarbon 51(1):1–43.Google Scholar
Pearson, A, Eglinton, T. 2000. The origin of n-alkanes in Santa Monica Basin surface sediment: a model based on compound-specific Δ14C and δ13C data. Organic Geochemistry 31(11):1103–16.CrossRefGoogle Scholar
Pearson, A, Ingalls, AE, Shah, SR, Hansman, RL, Aluwihare, LI, Santos, GM, Griffin, S, Druffel, ERM. 2005. Exploring the minimum sample size limit for CSRA: lessons from the water column [abstract]. 10th International Conference on Accelerator Mass Spectrometry, Berkeley, California, USA, 5–10 September 2005.Google Scholar
Quarta, G, D'Elia, M, Calcagnile, L. 2004. The influence of injection parameters on mass fractionation phenomena in radiocarbon analysis. Nuclear Instruments and Methods in Physics Research B 217(4):644–8.Google Scholar
Santos, GM, Southon, JR, Druffel-Rodriguez, K, Griffin, S, Mazon, M. 2004. Magnesium perchlorate as an alternative water trap in AMS graphite sample preparation: a report on sample preparation at the KCCAMS Facility at the University of California, Irvine. Radiocarbon 46(1):165–73.CrossRefGoogle Scholar
Santos, GM, Southon, JR, Griffin, S, Beaupre, SR, Druffel, ERM. 2007a. Ultra small-mass AMS 14C sample preparation and analyses at KCCAMS/UCI Facility. Nuclear Instruments and Methods in Physics Research B (259):293–302.CrossRefGoogle Scholar
Santos, GM, Mazon, M, Southon, JR, Rifai, S, Moore, R. 2007b. Evaluation of iron and cobalt powder brands for suitable catalyst for 14C-AMS target preparation. Nuclear Instruments and Methods in Physics Research B 259(1):308–15.Google Scholar
Santos, GM, Moore, RB, Southon, JR, Griffin, S, Hinger, E, Zhang, D. 2007c. AMS 14C sample preparation at the KCCAMS/UCI Facility: status report and performance of small samples. Radiocarbon 49(2):255–69.Google Scholar
Santos, GM, Alexandre, A, Coe, HHG, Reyerson, PE, Southon, JR, De Carvalho, CN. 2010. The phytolith 14C puzzle: a tale of background determinations and accuracy tests. Radiocarbon 52(1):113–28.Google Scholar
Shah, SR, Pearson, A. 2007. Ultra-microscale (5–25 μg C) analysis of individual lipids by 14C AMS: assessment and correction for sample processing blank. Radiocarbon 49(1):69–82.Google Scholar
Southon, J, Santos, GM. 2007. Life with MC-SNICS. Part II: recent ion source development at the Keck Carbon Cycle AMS Facility. Nuclear Instruments and Methods in Physics Research B 259(1):88–93.CrossRefGoogle Scholar
Vogel, JS, Nelson, DE, Southon, JR. 1987. 14C background levels in an accelerator mass spectrometry system. Radiocarbon 29(3):323–33.Google Scholar
Zelles, L. 1999. Fatty acid patterns of phospholipids and lipopolysaccharides in the characterisation of microbial communities in soil: a review. Biology and Fertility of Soils 29(2):111–29.Google Scholar
Zencak, Z, Reddy, CM, Teuten, EL, Xu, L, McNichol, AP, Gustafsson, Ö. 2007. Evaluation of gas chromatographic isotope fractionation and process contamination by carbon in compound-specific radiocarbon analysis. Analytical Chemistry 79(5):2042–9Google Scholar
Ziolkowski, LA, Druffel, ERM. 2009. Quantification of extraneous carbon during compound specific radiocarbon analysis of black carbon. Analytical Chemistry 81(24):10,156–61.Google Scholar