Towards the limits: Analysis of microscale 14C samples using EA-AMS

Welte, Caroline; Hendriks, Laura; Wacker, Lukas; Haghipour, Negar; Eglinton, Timothy I.; Günther, Detlef; Synal, Hans-Arno

doi:10.1016/j.nimb.2018.09.046

Cited by 32 publications

(29 citation statements)

References 31 publications

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“…Sn boats and capsules thus introduce similar amounts of contamination. Our results determined with blank material combusted in Sn containers are in a similar range to results of other studies, which however combusted empty Sn containers including Welte et al (2018; We have so far not tested heat treatment (550°C) of DCM-washed Sn vessels, which can further reduce contamination levels (Welte et al 2018). The size series combusted in Ag capsules gave 14 C concentrations, which are about one order of magnitude higher, between 0.1921 ± 0.0293 -0.5492 ± 0.0322 F 14 C, than for the Sn containers and the data show no size dependency but scatter strongly (Figure 3).…”

Section: Ea-gis-ams Measurementssupporting

confidence: 91%

“…In addition, we tested different EA sample containers including Sn boats and capsules cleaned with DCM, which removes contamination more efficient than Acetone or Milli-Q water (Welte et al 2018;Ruff et al 2010a), and Ag capsules cleaned by heating at 450°C. To directly compare the results for the Sn boats and Sn capsules, we calculated the amount of exogenous C for each series using the parameters obtained from the combined ampoule data set (F 14 C c = 0.93 ± 0.23) ( Table 1).…”

Section: Ea-gis-ams Measurementsmentioning

confidence: 99%

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

et al. 2019

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Increasing demands for small-scale radiocarbon (14C) analyses required the installation of a “SO-110 B” type ion source (HVE Europa B.V.) at our 6 MV Tandetron AMS (HVE) dedicated for the direct injection of CO2 using either the gas injection system (GIS) from Ionplus AG or a EuroVector EA 3000 elemental analyzer (EA). We tested both systems with multiple series of 14C-free and modern standards (2.5–50 µg C) combusted in quartz ampoules or EA containers and were able to quantify exogenous C introduced. In EA-GIS-AMS analysis exogenous C is mainly derived from the EA sample containers. Blank values for 50 µg C combusted in solvent-cleaned tin (Sn) vessels were 0.0127 ± 0.0012 F14C (boats) and 0.0090 ± 0.0010 F14C (capsules), while they were much higher for thermally cleaned silver (Ag) capsules. The processing of gas samples for GIS-AMS yields similar blank values corresponding to 0.30 ± 0.08 µg exogenous C with 0.93 ± 0.23 F14C consisting of 0.28 µg C modern and 0.02 µg C fossil C. The combustion of larger amounts of blank material (1 mg C) in a single quartz tube split into aliquots gives lower blanks (0.0064 ± 0.0008 F14C; 50 µg C). Thus, 14C analysis of small, gaseous samples is now possible at CologneAMS.

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Section: Ea-gis-ams Measurementssupporting

confidence: 91%

Section: Ea-gis-ams Measurementsmentioning

confidence: 99%

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

et al. 2019

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“…Both the cleaned canvas material and paint sample were directly measured on the AMS as carbon dioxide following combustion in an elemental analyzer (8). Owing to the ultrasmall sample size, constant contamination was considered and accordingly corrected (33, 34). Radiocarbon results are reported as 14 C ages (before 1950) and as fraction modern F 14 C for samples younger than 1950 (35).…”

Section: Methodsmentioning

confidence: 99%

Uncovering modern paint forgeries by radiocarbon dating

Hendriks

Hajdas

Ferreira

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Art forgeries have existed since antiquity, but with the recent rapidly expanding commercialization of art, the approach to art authentication has demanded increasingly sophisticated detection schemes. So far, the most conclusive criterion in the field of counterfeit detection is the scientific proof of material anachronisms. The establishment of the earliest possible date of realization of a painting, called the terminus post quem, is based on the comparison of materials present in an artwork with information on their earliest date of discovery or production. This approach provides relative age information only and thus may fail in proving a forgery. Radiocarbon (14C) dating is an attractive alternative, as it delivers absolute ages with a definite time frame for the materials used. The method, however, is invasive and in its early days required sampling tens of grams of material. With the advent of accelerator mass spectrometry (AMS) and further development of gas ion sources (GIS), a reduction of sample size down to microgram amounts of carbon became possible, opening the possibility to date individual paint layers in artworks. Here we discuss two microsamples taken from an artwork carrying the date of 1866: a canvas fiber and a paint chip (<200 µg), each delivering a different radiocarbon response. This discrepancy uncovers the specific strategy of the forger: Dating of the organic binder delivers clear evidence of a post-1950 creation on reused canvas. This microscale 14C analysis technique is a powerful method to reveal technically complex forgery cases with hard facts at a minimal sampling impact.

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“…The reextracted and pre-heated n-alkane fractions (step 2) were analyzed at the LIP AMS (ETH Nr's.). F 14 C results were corrected for constant contamination according to Welte et al (2018) with a fossil n-alkane standard (C28 with F 14 C = 0) and a modern n-alkane standard (C32 with F 14 C = 1.073). Constant contamination correction yielded 4.3 µg C for a single cap, with F 14 C values of 0.895.…”

Section: C Measurementsmentioning

confidence: 99%

Age and origin of leaf wax <i>n</i>-alkanes in fluvial sediment-paleosol sequences, and implications for paleoenvironmental reconstructions

Bliedtner¹,

Suchodoletz²,

Schäfer³

et al. 2019

Preprint

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Abstract. Leaf wax n-alkanes are increasingly used for quantitative reconstructions of past environmental changes. However, this is complicated in sediment archives with associated hydrological catchments since the stored n-alkanes can have different ages and origins. Direct 14C-dating of the n-alkanes has a great potential to derive independent age information for these proxies, allowing their correct paleoenvironmental interpretation. This holds also true for fluvial sediment-paleosols sequences (FSPS), where the n-alkane signal is divided into (i) a catchment signal that is deposited with fluvial sediments, and (ii) an in-situ signal from local biomass that increasingly dominates (paleo)soils with time. Therefore, age and origin of n-alkanes in FSPS are complex: In fluvial sediment layers they can be pre-aged and reworked when originating from eroded catchment soils, or originate from organic-rich sediment rocks in the catchment. In (paleo)soils, besides an inherited contribution from the catchment they were formed in-situ during pedogenesis and originate from local biomass. Depending on the different relative contributions from these sources, the n-alkane signal from an FSPS can show variable age offsets between its formation and final deposition. During this study, we applied compound-class 14C-dating to n-alkanes from a fluvial sediment-paleosol sequence (FSPS) along the upper Alazani River in eastern Georgia with Jurassic black clay shales in its upper catchment. Our results show that pre-heating the n-alkanes with 120 °C for 8 h before 14C-dating effectively removed the shorter chains (

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Towards the limits: Analysis of microscale 14C samples using EA-AMS

Cited by 32 publications

References 31 publications

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

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

Uncovering modern paint forgeries by radiocarbon dating

Age and origin of leaf wax <i>n</i>-alkanes in fluvial sediment-paleosol sequences, and implications for paleoenvironmental reconstructions

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Towards the limits: Analysis of microscale 14C samples using EA-AMS

Cited by 32 publications

References 31 publications

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

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

Uncovering modern paint forgeries by radiocarbon dating

Age and origin of leaf wax &lt;i&gt;n&lt;/i&gt;-alkanes in fluvial sediment-paleosol sequences, and implications for paleoenvironmental reconstructions

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

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

Age and origin of leaf wax <i>n</i>-alkanes in fluvial sediment-paleosol sequences, and implications for paleoenvironmental reconstructions