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Is the Consensus Value of ANU Sucrose (IAEA C-6) Too High?

Published online by Cambridge University Press:  18 July 2016

Xiaomei Xu ,
Matthew S Khosh ,
Kevin C Druffel-Rodriguez ,
Susan E Trumbore  and
John R Southon
Xiaomei Xu*
Affiliation:
Keck AMS Facility, Earth System Science Department, University of California, Irvine, California 92697, USA
Matthew S Khosh
Affiliation:
Keck AMS Facility, Earth System Science Department, University of California, Irvine, California 92697, USA
Kevin C Druffel-Rodriguez
Affiliation:
Keck AMS Facility, Earth System Science Department, University of California, Irvine, California 92697, USA
Susan E Trumbore
Affiliation:
Keck AMS Facility, Earth System Science Department, University of California, Irvine, California 92697, USA
John R Southon
Affiliation:
Keck AMS Facility, Earth System Science Department, University of California, Irvine, California 92697, USA
*
Corresponding author. Email: xxu@uci.edu.
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Abstract

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Primary and secondary standards are essential in radiocarbon analyses for the purpose of reporting and comparing data among laboratories, as well as for internal laboratory data quality control. ANU sucrose is one of the IAEA-certified 14C standards (C-6) with a consensus value of 1.5061 ± 0.0011 fraction modern (Fm). All of our measurements of ANU sucrose (n = 351) as a secondary standard over the last 7 yr result in an average value of 1.5016 ± 0.0005 Fm (2-σ standard error). After applying the same outlier tests used for IAEA reference standards, a weighted average value of 1.5016 ± 0.0002 Fm (n = 294) was calculated. This value is significantly lower than the IAEA C-6 consensus value (t test with unequal variance; p = 0.023). In contrast, our measurements of other secondary standards over the same time period are in excellent agreement with their respective consensus values. Since ANU is the only secondary standard measured in our lab that does not agree with the consensus values, and we have measured a larger number analyses compared to what went into the definition of the consensus value, we suggest that the consensus value of ANU sucrose might be too high by ∼0.0045 ± 0.0011 Fm. Given that some labs routinely use ANU sucrose as a primary standard, our results suggest that revisiting the consensus value of ANU sucrose may be necessary.

Type
Calibration, Data Analysis, and Statistical Methods
Information
Radiocarbon , Volume 52 , Issue 3: 20th Int. Radiocarbon Conference Proceedings , 2010 , pp. 866 - 874
Copyright
Copyright © 2010 by the Arizona Board of Regents on behalf of the University of Arizona 

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