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Abstract. Extraction procedures for in situ cosmogenic 14C (in situ 14C) fromquartz require quantitative isotopic yields while maintaining scrupulousisolation from atmospheric and organic 14C. These time- and labor-intensiveprocedures are ripe for automation; unfortunately, our original automatedin situ 14C extraction and purification systems, reconfigured and retrofittedfrom our original systems at the University of Arizona, proved less reliablethan hoped. We therefore installed a fully automated stainless-steel system(except for specific borosilicate glass or fused-silica components)incorporating more reliable valves and improved actuator designs, along witha more robust liquid nitrogen distribution system. As with earlier versions,the new system uses a degassed lithium metaborate (LiBO2) flux to dissolvethe quartz sample in an ultra-high-purity oxygen atmosphere, after alower-temperature combustion step to remove atmospheric and organic 14C. We compared single-use high-purity Al2O3 against reusable90 %Pt / 10 %Rh (Pt/Rh) sample combustion boats. The Pt/Rh boats heat moreevenly than the Al2O3, reducing procedural blank levels andvariability for a given LiBO2 flux. This lower blank variability alsoallowed us to trace progressively increasing blanks to specific batches offluxes from our original manufacturer. Switching to a new manufacturerreturned our blanks to consistently low levels on the order of (3.4 ± 0.9) × 104 14C atoms. We also analyzed the CRONUS-A intercomparison material to investigatesensitivity of extracted 14C concentrations to the temperature andduration of the combustion and extraction steps. Results indicate that 1 hcombustion steps at either 500 or 600 ∘C yield results consistentwith the consensus value of Jull et al. (2015), while 2 hat 600 ∘C results in loss of ca. 9 % of the high-temperature14C inventory. Results for 3 h extractions at temperatures rangingfrom 1050 to 1120 ∘C and 4.5 h at 1000 ∘Cyielded similar results that agreed with the nominal value andpublished results from most laboratories. On the other hand, an extractionfor 3 h at 1000 ∘C was judged to be incomplete due to asignificantly lower measured concentration. Based on these results, ourpreferred technique is now combustion for 1 h at 500 ∘C followedby a 3 h extraction at 1050 ∘C. Initial analyses of the CoQtz-Nintercomparison material at our lab yielded concentrations ca. 60 % lowerthan those of CRONUS-A, but more analyses of this material from this andother labs are clearly needed to establish a consensus value.