Progress in automated extraction and purification of in situ 14C from quartz: Results from the Purdue in situ 14C laboratory

[摘要] Current extraction methods for in situ C-14 from quartz [e.g., Lifton et al., (2001), Pigati et al., (2010), Hippe et al., (2013)1 are time-consuming and repetitive, making them an attractive target for automation. We report on the status of in situ C-14 extraction and purification systems originally automated at the University of Arizona that have now been reconstructed and upgraded at the Purdue Rare Isotope Measurement Laboratory (PRIME Lab). The Purdue in situ C-14 laboratory builds on the flow-through extraction system design of Pigati et al. (2010), automating most of the procedure by retrofitting existing valves with external servo-controlled actuators, regulating the pressure of research purity O-2 inside the furnace tube via a PID-based pressure controller in concert with an inlet mass flow controller, and installing an automated liquid N-2 distribution system, all driven by LabView (R) software. A separate system for cryogenic CO2 purification, dilution, and splitting is also fully automated, ensuring a highly repeatable process regardless of the operator. We present results from procedural blanks and an intercomparison material (CRONUS-A), as well as results of experiments to increase the amount of material used in extraction, from the standard 5 g to 10 g or above. Results thus far are quite promising with procedural blanks comparable to previous work and significant improvements in reproducibility for CRONUS-A measurements. The latter analyses also demonstrate the feasibility of quantitative extraction of in situ C-14 from sample masses up to 10 g. Our lab is now analyzing unknowns routinely, but lowering overall blank levels is the focus of ongoing research. (C) 2015 Elsevier B.V. All rights reserved.

[发布日期] 2015-10-15

[效力级别]  Proceedings Paper

[关键词] Carbon-14;Cosmogenic;Carbon isotopes;Automation techniques