Treatment of small samples of particulate organic carbon (POC) for radiocarbon dating of ice

Drosg, Roswitha; Kutschera, W.; Scholz, Kathrin; Steier, Peter; Wagenbach, Dietmar; Wild, Eva Maria

doi:10.1016/j.nimb.2007.02.094

Cited by 10 publications

(9 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These drawbacks may be partly overcome by changing the Fe/C ratio and the use of smaller graphitization reactors, but the graphitization of small samples is cumbersome and ultra-small samples remain difficult to graphitize. Hence, only few laboratories are able to convert a few micrograms of carbon to graphite with a reasonable yield and blank value [3,4]. In spite of these problems, the demand to measure small and ultra-small samples has increased in the last couple of years.…”

Section: Introductionmentioning

confidence: 99%

Improving a gas ion source for 14C AMS

Fahrni

Wacker

Synal

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

108

104

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Improving a gas ion source for 14C AMS

Fahrni

Wacker

Synal

et al. 2013

Nuclear Instruments and Methods in Physics Research Section B:

108

104

View full text Add to dashboard Cite

“…The extraction of WIOC from the ice is straightforward as it can be collected by filtration of the melted ice. Note that in previous publications Zapf et al, 2013) the term POC was used for particulate organic carbon (Drosg et al, 2007). Since POC can be mistaken for primary organic carbon (Gelencsér, 2004;Zhang et al, 2012), we adopted the term water-insoluble organic carbon (WIOC) instead in this overview.…”

mentioning

confidence: 99%

Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

et al. 2016

View full text Add to dashboard Cite

Abstract. High-altitude glaciers and ice caps from midlatitudes and tropical regions contain valuable signals of past climatic and environmental conditions as well as human activities, but for a meaningful interpretation this information needs to be placed in a precise chronological context. For dating the upper part of ice cores from such sites, several relatively precise methods exist, but they fail in the older and deeper parts, where plastic deformation of the ice results in strong annual layer thinning and a non-linear age-depth relationship. If sufficient organic matter such as plant, wood or insect fragments were found, radiocarbon ( 14 C) analysis would have thus been the only option for a direct and absolute dating of deeper ice core sections. However such fragments are rarely found and, even then, they would not be very likely to occur at the desired depth and resolution. About 10 years ago, a new, complementary dating tool was therefore introduced by our group. It is based on extracting the µg-amounts of the water-insoluble organic carbon (WIOC) fraction of carbonaceous aerosols embedded in the ice matrix for subsequent 14 C dating. Since then this new approach has been improved considerably by reducing the measurement time and improving the overall precision. Samples with ∼ 10 µg WIOC mass can now be dated with reasonable uncertainty of around 10-20 % (variable depending on sample age). This requires about 300 to 800 g of ice for WIOC concentrations typically found in midlatitude and low-latitude glacier ice. Dating polar ice with satisfactory age precision is still not possible since WIOC concentrations are around

show abstract

“…Our approach to reduce the sample size limit down to a few g carbon pursues investigations presented in Steier et al (2006) and Drosg et al (2007). Studies at our own laboratory and work by other groups (Gagnon et al 2000;Hua et al 2004;Santos et al 2007;Southon 2007) suggest that the standard procedure to convert sample carbon into graphite (Vogel et al 1984), suitable for standard accelerator mass spectrometry (AMS) ion sources, has the potential to be extended down to samples of 10 g carbon or below.…”

Section: Introductionmentioning

confidence: 93%

“…Table 1 show results from measurement series where different sample preparation methods were tried out to find the optimum procedure. In general, the data represents the development from what is described in Drosg et al (2007) towards the procedure given above. Different amounts of 13 C-enriched glucose ( 13 C >99%) and DNA ( 13 C >98%) were applied.…”

Section: C-enriched Materialsmentioning

confidence: 99%

Studies on the Preparation of Small ¹⁴C Samples with an RGA and ¹³C-Enriched Material

et al. 2010

Self Cite

View full text Add to dashboard Cite

ABSTRACT. The minimum size of radiocarbon samples for which reliable results can be obtained in an accelerator mass spectrometry (AMS) measurement is in many cases limited by carbon contamination introduced during sample preparation (i.e. all physical and chemical steps to which samples were subjected, starting from sampling). Efforts to reduce the sample size limit down to a few g carbon require comprehensive systematic investigations to assess the amount of contamination and the process yields. We are introducing additional methods to speed up this process and to obtain more reliable results. A residual gas analyzer (RGA) is used to study combustion and graphitization reactions. We could optimize the reaction process at small CO 2 pressures and identify detrimental side reactions. Knowing the composition of the residual gas in a graphitization process allows a reliable judgment on the completeness of the reaction. Further, we use isotopically enriched 13 C (98% 13 C) as a test material to determine contamination levels. This offers significant advantages: 1) The measurement of 12 C/ 13 C in CO 2 is possible on-line with the RGA, which significantly reduces turnaround times compared to AMS measurements; 2) Both the reaction yield and the amount of contamination can be determined from a single test sample.The first applications of isotopically enriched 13 C and the RGA have revealed that our prototype setup has room for improvements via better hardware; however, significant improvements of our sample processing procedures were achieved, eventually arriving at an overall contamination level of 0.12 to 0.15 g C during sample preparation (i.e. freeze-drying, combustion, and graphitization) of g-sized samples in aqueous solution, with above 50% yield.

show abstract

Treatment of small samples of particulate organic carbon (POC) for radiocarbon dating of ice

Cited by 10 publications

References 12 publications

Improving a gas ion source for 14C AMS

Improving a gas ion source for 14C AMS

Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

Studies on the Preparation of Small ¹⁴C Samples with an RGA and ¹³C-Enriched Material

Contact Info

Product

Resources

About

Treatment of small samples of particulate organic carbon (POC) for radiocarbon dating of ice

Cited by 10 publications

References 12 publications

Improving a gas ion source for 14C AMS

Improving a gas ion source for 14C AMS

Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

Studies on the Preparation of Small 14C Samples with an RGA and 13C-Enriched Material

Contact Info

Product

Resources

About

Studies on the Preparation of Small ¹⁴C Samples with an RGA and ¹³C-Enriched Material