Bag of Tricks: A Set of Techniques and other Resources to Help ¹⁴C Laboratory Setup, Sample Processing, and Beyond

Abstract

Over the last few decades, radiocarbon laboratories have used different procedures for measuring a broad range of carbonaceous materials. To produce reliable results, the processes employed for sample processing, graphite target production, and spectrometer measurement must be rigorous, well tested, and reproducible. Most of the procedures have been developed, improved, and published as part of the laboratories’ quality control and research programs, and can be frequently found in the literature. Nevertheless, there are suites of laboratory techniques (or “small useful skills”), products, and other resources that either have never been described in publications, or have been somewhat hidden in much larger scientific articles and reports. We feel that with the rapid rise of newer laboratories and facilities, a set of resourceful suggestions might come in handy. Here we gathered these skill sets that can be used in all aspects of 14C sample processing, with the intention to simplify and expedite procedures, from glass-tube making to graphitization and measurements. We also included some miscellaneous items to help in laboratory setup.

Exploring sample size limits of AMS gas Ion Source 14C analysis at Cologneams

“…ampoules and the subsequent combustion as also observed by Santos et al (2010) and Santos and Xu (2017). The constant contamination for the total data set (n = 44 POC #3 and n = 27 Ox-II standards) consists of 0.30 ± 0.08 μg C ( Figure 1C).…”

“…The quartz ampoules, cupric oxide (CuO rods, 0.65 × 3 mm, p.a., MERCK KGaA, Germany), and Ag wires (MERCK KGaA, Germany) were pre-combusted at 900°C for 4 hr, while the borosilicate glass tubes were combusted at 450°C for 4 hr. Then the sample was filled into the cleaned quartz tubes using Sn boats for weighing and transferring together with the CuO (CuO:C ratio of about 60:1) and 5 mg Ag wires (Santos and Xu 2017). The ampoules were evacuated (P < 10 -4 mbar), flame sealed, and heated in a muffle furnace to combust the standard material to CO 2 (900°C, 4 h).…”

Growth Assessment of Native Tree Species from the Southwestern Brazilian Amazonia by Post-AD 1950 14C Analysis: Implications for Tropical Dendroclimatology Studies and Atmospheric 14C Reconstructions

“…Next, they were subjected to lignification and chlorification by means of an acid-base-acid pretreatment (1N HCl and NaOH at 70 • C for 30 min each, until supernatant was clear) [67], followed by a bleaching step (1N HCl and 1M NaClO 2 at 70 • C in a fume hood for approximately 6 h) to isolate holocellulose. Hemicellulose was then removed in a 17.5% NaOH solution at room temperature for approximately 1-2 hrs maximum, followed by one rinsed with 1N HCl to remove any labile atmospheric CO 2 uptake during the NaOH treatment [68]. The final insoluble organic portion is referred to as α-cellulose, and it was subsequently rinsed with warm ultrapure water (~18 MΩ.cm) until pH 6 was reached, then homogenized, dried, and stored for later processing.…”

“…The CO 2 produced during combustion was cryogenically separated from other gasses and then reduced to filamentous graphite by Zn processing, following established protocols (e.g., [68], and references therein). Two wood reference materials, AVR wood-blank ( 14 C-free) and barley mash FIRI-J (post-AD 1950 14 C), were processed alongside samples to facilitate background corrections and quality control of the chemical extractions.…”

Supplementary material to &quot;Inter-comparison of the Elemental and Organic Carbon Mass Measurements from Three North American National Long-term Monitoring Networks&quot;

“…Mass fractions of TC, OC and EC isolated by the ECT9 protocol using a Sunset Laboratory instrument (Huang et al, 2006) was shipped to KCCAMS/UCI as cryogenically trapped CO2 in sealed ampules followed by a separated set of reference materials. Isolated CO2 samples were then converted to filamentous graphite following specific protocols (Santos and Xu, 2017) and analyzed for their carbon isotopes. Radiocarbon results as FM (fraction modern carbon) were corrected for background effects and isotopic fractionation with  13 C of prepared graphite measured directly at the spectrometer, as described by Santos et al (2007).…”