scholarly journals New Possibilities for 14C Measurements by Liquid Scintillation Counting

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 387-392 ◽  
Author(s):  
Ramon Aravena ◽  
Robert R Drimmie ◽  
Riffat M Qureshi ◽  
Roger McNeely ◽  
Sandy Fabris
Keyword(s):  
Carbon Content ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Standard Sample ◽  
Scintillation Counting ◽  
Small Samples ◽  
Low Carbon ◽  
Direct Absorption ◽  
Organic Solution ◽  
Good Agreement

Results of intercomparison tests are presented on samples analyzed using gas and liquid scintillation techniques to study the capability of the LKB Quantulus to count an organic solution used for direct absorption of CO2 and samples with low carbon content. Good agreement was obtained for small samples compared to standard sample size and for the direct absorption compared with the traditional techniques.

The Brazilian AMS Radiocarbon Laboratory (LAC-UFF) and the Intercomparison of Results with CENA and UGAMS

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 325-330 ◽  
Author(s):  
K D Macario ◽  
P R S Gomes ◽  
R M Anjos ◽  
C Carvalho ◽  
R Linares ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Latin America ◽  
Liquid Scintillation Counting ◽  
Nuclear Energy ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Physics Institute ◽  
University Of Georgia ◽  
The University ◽  
Good Agreement

After 22 yr of the low-level liquid scintillation counting 14C laboratory at the Center for Nuclear Energy in Agriculture (CENA) at São Paulo University (USP), Piracicaba, Brazil, and several collaborative projects with Brazilian and international researchers from distinct scientific areas, the first 14C accelerator mass spectrometry (AMS) laboratory in Latin America was installed at the Physics Institute of the Universidade Federal Fluminense (UFF), Niterói, Brazil. A 250kV single stage accelerator produced by National Electrostatics Corporation began its operation in 2012. In this work, we compare measurements performed at the AMS Radiocarbon Laboratory at UFF (LAC-UFF) with those performed at CENA and the University of Georgia (UGAMS), Georgia, USA. All the results obtained from distinct inorganic and organic samples were in very good agreement.

scholarly journals Tartu Radiocarbon Dates XIII

Radiocarbon ◽  
1994 ◽  
Vol 36 (1) ◽  
pp. 153-158
Author(s):  
Arvi Liiva ◽  
Ilze Loze
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Half Life ◽  
Liquid Scintillation ◽  
Standard Sample ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
Academy Of Sciences ◽  
Modern Standard

This date list reports dates of archaeological samples of Mesolithic and Neolithic sites of Estonia, Latvia and Lithuania. We use liquid scintillation counting at the Geochemical and Statistical Laboratory of the Institute of Zoology and Botany, Estonian Academy of Sciences. Our modern standard is benzene enriched in 14C and its activity is checked with an NBS oxalic acid standard sample. Dates are given in conventional 14C years, based on the Libby half-life of 5570 ± 30 yr. AD 1950 is the reference year. Errors are based on one standard deviation calculated from count rates.

Use of 125I-labeled-histamine-cyclosporin C for monitoring serum cyclosporine concentrations in transplantation patients.

1986 ◽  
Vol 32 (3) ◽  
pp. 492-495 ◽  
Author(s):  
P Y Wong ◽  
M Cheung ◽  
T K Yip ◽  
A V Mee
Keyword(s):  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Gamma Counting ◽  
Analytical Recovery ◽  
Bile Extract ◽  
Good Agreement

Abstract We synthesized an 125I-labeled-histamine-cyclosporin C tracer, to obviate the use of tritiated tracer in radioimmunoassay of cyclosporine. With this tracer, the assay results varied linearly with concentration up to at least 800 micrograms/L. The within-assay CV was 6.6% at 39 micrograms/L, 4.2% at 100 micrograms/L, and 7.0% at 300 micrograms/L (n = 15). The between-assay CV was 10.0, 6.4, and 7.8% for the same respective concentrations. Comparison with an assay involving tritiated tracer (x) showed good agreement of results: y = 3.81 + 0.927x (r = 0.975, n = 604). Analytical recovery ranged from 100 to 106%. We also compared another commercially available radioiodinated tracer ("125Iodocyclosporin"; Immunonuclear Corp.). Our tracer appeared to be more specific for cyclosporine, as determined by assaying chromatographic fractions of bile extract from a patient being treated with cyclosporine. Results with use of our tracer compared favorably with those obtained with the tritiated tracer, and our assay has the advantages of gamma counting vs liquid-scintillation counting.

Upgrade of the CO2 Direct Absorption Method for Low-Level 14C Liquid Scintillation Counting

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 260-267 ◽  
Author(s):  
Chiara Canducci ◽  
Paolo Bartolomei ◽  
Giuseppe Magnani ◽  
Antonietta Rizzo ◽  
Angela Piccoli ◽  
...  
Keyword(s):  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Closed Loop ◽  
Scintillation Counting ◽  
Gaseous Emissions ◽  
Direct Absorption ◽  
Absorption Method ◽  
Fossil Carbon ◽  
Measurement Protocol ◽  
Background Counting

A new system for CO2 absorption and liquid scintillation counting (LSC) was designed and developed along with its inherent measurement protocol for radiocarbon analysis in gaseous emissions, fuels, and biobased products. CO2 is chemically trapped as a carbamate in a suitable absorbing solution (3-methoxy-propyl-amine), gravimetrically measured, and analyzed by LSC (using a QuantulusTM 1220) to determine the 14C content. The use of cryogenic traps and a pressure transducer in the system prevents the need for closed-loop recirculation or additional steps to maximize CO2 capture in a short amount of time. The choice of PTFE vials used both for CO2 pretreatment and subsequent LSC analysis provides the opportunity to significantly reduce the background counting down to 40% with respect to the low-40K glass vials. This upgrade resulted in improving the maximum detectable age back to 36,000 yr BP in routine measurements. This method therefore turns out to be flexible enough to be applied for 14C dating as well as to differentiate between modern and fossil carbon.

scholarly journals Assessment of 0.3-ml Minivials for Radiocarbon Dating by Liquid Scintillation Counting of Benzene

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 389-393 ◽  
Author(s):  
A. G. Hogg
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Small Samples ◽  
Vacuum System ◽  
Radiocarbon Dates ◽  
Significant Potential ◽  
Accuracy And Precision ◽  
Potential Problems

I have made an evaluation of 0.3-ml minivials for 14C dating of small samples by liquid scintillation counting of benzene. A calibrated wood standard was diluted by varying amounts of ancient CO2, with synthesized benzene counted in both conventional 3.0-ml vials and 0.3-ml minivials in a 1220 Quantulus. The accuracy and precision of results are compared for samples ranging in weight from 50 to 240 mg of carbon. I examined two significant potential problems associated with handling small samples, namely, memory effects within the vacuum system, and signal within the dilution gas. Although accurate radiocarbon dates can be obtained using either standard vials or minivials, minivials are more suitable for dating small samples because they are less influenced by these sources of error.

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