A Suitable procedure for preparing of water Samples used in Radiocarbon Intercomparison

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 1879-1887
Author(s):  
H A Takahashi ◽  
M Minami ◽  
T Aramaki ◽  
H Handa ◽  
Y Saito-Kokubu ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Water Samples ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Chemical Compositions ◽  
Hazardous Material

ABSTRACTWe studied a suitable procedure for preparing of water samples used in radiocarbon intercomparisons involving dissolved inorganic carbon (DIC). The water samples must have inter-batch consistency and stable 14C concentrations and no sterilizing agent (e.g., HgCl2) should be added, in order to avoid the production of hazardous material. Six water samples, containing widely different amounts and types of salts, DIC, and 14C concentrations (1–100 pMC), were prepared in order to assess the procedure. Sample consistency was investigated through δ13C and chemical compositions; their low variabilities indicate that our procedure can be applied to radiocarbon intercomparison. A specific sample preparation protocol was developed for this kind of applications.

scholarly journals Applying the Direct Absorption Method and LSC for 14C Concentration Measurement in Aqueous Samples

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Carmen Varlam ◽  
Ioan Stefanescu ◽  
Mihai Varlam ◽  
Irina Popescu ◽  
Ionut Faurescu
Keyword(s):  
Sample Preparation ◽  
Water Samples ◽  
Liquid Scintillation ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Measurement Procedure ◽  
Direct Absorption ◽  
Absorption Method ◽  
Aqueous Samples ◽  
Working Parameters

We investigated a simple, reliable radiocarbon measurement procedure for water samples using the direct absorption method for sample preparation, followed by low-level liquid scintillation spectrometry. This process has involved quantitative evaluation of the conversion steps in order to estimate the appropriate working parameters. The 14C activity of dissolved inorganic carbon (DIC) for several types of water (ranging from seawater to groundwater) has been measured, paying attention to the preparation requirements of each type of water. The main advantage of this method is the simplified sample preparation, allowing measurement of a great number of samples in less time. This method was designed for routine analysis of water samples, and it is proposed particularly for use in 14C monitoring programs of CANDU-type reactors.

scholarly journals Increase of 14C Activity of Dissolved Inorganic Carbon Along a River Course

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 515-521 ◽  
Author(s):  
Dušan Srdoč ◽  
Ines Krajcar-Bronić ◽  
Nada Horvatinčić ◽  
Bogomil Obelić
Keyword(s):  
Aquatic Plants ◽  
Water Samples ◽  
Organic Material ◽  
Root Respiration ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Exchange Process ◽  
Karst Spring ◽  
Stream Waters

Results of measurements for 3 years (1981–1983) of 14C activity of dissolved inorganic carbon (DIG) in water samples from the Korana River, as well as that of recent tufa and aquatic plants, showed that 14C concentration increases from karst spring to the estuary. A model describing the increase of 14C activity was developed assuming that the increase is due to the exchange of the dissolved CO2 in stream water with atmospheric CO2 and to dissolution of CO2 from the decay of organic material and root respiration. It is possible to distinguish these two contributions by measuring the δ13C values of DIC in water. As expected, our data show that the exchange process between atmospheric CO2 and DIC dominates at rapids and waterfalls, while biologic contribution is much higher in lakes and along the lowland flow of the Korana River. Agreement between the calculated and the measured activities supports the proposed mechanisms of chemical and isotopic exchanges in stream waters.

scholarly journals A SIMPLE CO2 EXTRACTION METHOD FOR RADIOCARBON ANALYSES OF DISSOLVED INORGANIC CARBON IN WATER SAMPLES WITHOUT A CARRIER GAS

Radiocarbon ◽  
2021 ◽  
pp. 1-15
Author(s):  
Hiroshi A Takahashi ◽  
Hiroko Handa ◽  
Masayo Minami
Keyword(s):  
Water Samples ◽  
Extraction Method ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Cost Effective ◽  
Carrier Gas ◽  
Vacuum Line ◽  
Cost Effective Method ◽  
Wide Range ◽  
Cryogenic Trapping

ABSTRACT We developed a simple and cost-effective method for extracting carbon from dissolved inorganic carbon (DIC) in water samples without a carrier gas. This method only slightly modifies the existing vacuum line for CO2 purification in radiocarbon research laboratories by connecting several reservoirs and traps. The procedure consists of repeated cycles of CO2 extraction from water into the headspace of the reaction container, expansion of the extracted gas into the vacuum line, and cryogenic trapping of CO2. High CO2 yield (∼98%) was obtained from a variety of water samples with a wide range of DIC concentrations (0.4–100 mmol·L−1, in the case of 1.2 mgC). The δ13C fractionation depended on the CO2 yield, while the 14C concentration was constant within the error range, regardless of the CO2 yield. The average δ13C discrepancy between the results of this method and direct analyses made using the GC-IRMS was 0.02 ± 0.06‰. The standard deviations (1σ) in fraction of modern carbon (F14C) ranged from 0.0002 to 0.0004 for waters below 0.01 of F14C, and below 0.8% of F14C values for waters above 0.1. We conclude that this method is useful for effectively extracting CO2 from DIC in water and yields accurate 14C data.

scholarly journals Total dissolved inorganic carbon and physicochemical characteristics of surface microlayer and upper mixed layer water from Lagos Lagoon, Nigeria

2015 ◽  
Vol 17 (2) ◽  
pp. 334-343 ◽  
Keyword(s):  
Mixed Layer ◽  
Coastal Lagoon ◽  
Water Samples ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Physicochemical Characteristics ◽  
Total Alkalinity ◽  
Surface Microlayer ◽  
Total Dissolved Inorganic Carbon ◽  
Upper Mixed Layer

<p>The carbonate and physicochemical characteristics of the surface microlayer and upper mixed layer of a tropical coastal lagoon were investigated. Data on the physicochemical parameters generally indicated a moderately polluted ecosystem. The influence of the ocean environment over the Lagoon system was evident by elevated salinity levels. The mean total dissolved inorganic carbon (DIC) for the surface microlayer (SML) and subsurface water (SSW) samples were 2626.6 and 2550.9 &micro;mol/kg SW respectively. The dominant inorganic form of DIC in the lagoon water samples was HCO<sub>3</sub><sup>-</sup> with a calculated average abundance &gt;95.4% in the SML and &gt;94% in the SSW. The bicarbonate species derived abundance varied between 1.6% (SML) and 8.4% (SSW), while the aqueous carbon dioxide were generally low in percentages ranging from 0.4 in SSW to 1.5 in SML water samples. In general, the occurrence of the carbonate species was in the order HCO<sub>3</sub><sup>-</sup> &gt; CO<sub>3</sub><sup>2-</sup> &gt; CO<sub>2</sub>. Results showed that total alkalinity (A<sub>T</sub>) was relatively greater than the DIC. Long term monitoring studies in the coastal lagoon systems is needed to understand the coastal water chemistry and pollution status.</p>

scholarly journals GLODAPv2.2019 – an update of GLODAPv2

2019 ◽  
Vol 11 (3) ◽  
pp. 1437-1461 ◽  
Author(s):  
Are Olsen ◽  
Nico Lange ◽  
Robert M. Key ◽  
Toste Tanhua ◽  
Marta Álvarez ◽  
...  
Keyword(s):  
Quality Control ◽  
Water Samples ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
The Arctic ◽  
Global Ocean ◽  
Systematic Evaluation ◽  
Isotopic Tracers ◽  
Data Product

Abstract. The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface to bottom ocean biogeochemical data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of water samples. This update of GLODAPv2, v2.2019, adds data from 116 cruises to the previous version, extending its coverage in time from 2013 to 2017, while also adding some data from prior years. GLODAPv2.2019 includes measurements from more than 1.1 million water samples from the global oceans collected on 840 cruises. The data for the 12 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have undergone extensive quality control, especially systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but updated to WOCE exchange format and (ii) as a merged data product with adjustments applied to minimize bias. These adjustments were derived by comparing the data from the 116 new cruises with the data from the 724 quality-controlled cruises of the GLODAPv2 data product. They correct for errors related to measurement, calibration, and data handling practices, taking into account any known or likely time trends or variations. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 µmol kg−1 in dissolved inorganic carbon, 4 µmol kg−1 in total alkalinity, 0.01–0.02 in pH, and 5 % in the halogenated transient tracers. The compilation also includes data for several other variables, such as isotopic tracers. These were not subjected to bias comparison or adjustments. The original data, their documentation and DOI codes are available in the Ocean Carbon Data System of NOAA NCEI (https://www.nodc.noaa.gov/ocads/oceans/GLODAPv2_2019/, last access: 17 September 2019). This site also provides access to the merged data product, which is provided as a single global file and as four regional ones – the Arctic, Atlantic, Indian, and Pacific oceans – under https://doi.org/10.25921/xnme-wr20 (Olsen et al., 2019). The product files also include significant ancillary and approximated data. These were obtained by interpolation of, or calculation from, measured data. This paper documents the GLODAPv2.2019 methods and provides a broad overview of the secondary quality control procedures and results.

Filtration and exposure to benzalkonium chloride or sodium chloride to preserve water samples for dissolved inorganic carbon analysis

2019 ◽  
Vol 53 (5) ◽  
pp. 305-318
Author(s):  
Hiroshi A. Takahashi ◽  
Hiroko Handa ◽  
Ayumi Sugiyama ◽  
Makoto Matsushita ◽  
Miyuki Kondo ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Water Samples ◽  
Benzalkonium Chloride ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Analysis

scholarly journals Improvements in Procedural Blanks at NOSAMS: Reflections of Improvements in Sample Preparation and Accelerator Operation

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 683-691 ◽  
Author(s):  
A.P. McNichol ◽  
A. R. Gagnon ◽  
E. A. Osborne ◽  
D. L. Hutton ◽  
K.F. Von Reden ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sample Preparation ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Powder ◽  
Ocean Sciences ◽  
Accelerator Mass Spectrometer ◽  
One Step ◽  
Available Carbon ◽  
Seawater Samples

During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples—seawater, CaCO3 and organic carbon—to CO2 prior to preparing graphite for the accelerator and have distinct procedural blanks for each procedure. Dissolved inorganic carbon (∑CO2) is extracted from acidified seawater samples by sparging with a nitrogen carrier gas. We routinely analyze “line blanks” by processing CO2 from a 14C-dead source through the entire stripping procedure. Our hydrolysis blank, IAEA C-1, is prepared by acidifying in vacuo with 100% H3PO4 at 60° overnight, identical to our sample preparation. We use a dead graphite, NBS-21, or a commercially available carbon powder for our organic combustion blank; organic samples are combusted at 850° for 5 h using CuO to provide the oxidant. Analysis of our water stripping data suggests that one step in the procedure contributes the major portion of the line blank. At present, the contribution from the line blank has no effect on our seawater analyses (fraction modern (fm) between 0.7 and 1.2). Our hydrolysis blanks can have an fm value as low as 0.0006, but are more routinely between 0.0020 and 0.0025. The fm of our best organic combustion blanks is higher than those routinely achieved in other laboratories and we are currently altering our methods to reduce it.

scholarly journals GLODAPv2.2020 – the second update of GLODAPv2

2020 ◽  
Author(s):  
Are Olsen ◽  
Nico Lange ◽  
Robert M. Key ◽  
Toste Tanhua ◽  
Henry C. Bittig ◽  
...  
Keyword(s):  
Quality Control ◽  
Water Samples ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
The Arctic ◽  
Global Ocean ◽  
Systematic Evaluation ◽  
Isotopic Tracers ◽  
Data Product

Abstract. The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort providing regular compilations of surface to bottom ocean biogeochemical data, with an emphasis on seawater inorganic carbon chemistry and related variables determined through chemical analysis of water samples. GLODAPv2.2020 is an update of the previous version, GLODAPv2.2019. The major changes are: data from 106 more cruises added, extension of time coverage until 2019, and the inclusion of available discrete fugacity of CO2 (fCO2) values in the merged product files. GLODAPv2.2020 includes measurements from more than 1.2 million water samples from the global oceans collected on 946 cruises. The data for the 12 GLODAP core variables (salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon, total alkalinity, pH, CFC-11, CFC-12, CFC-113, and CCl4) have undergone extensive quality control, especially systematic evaluation of bias. The data are available in two formats: (i) as submitted by the data originator but updated to WOCE exchange format and (ii) as a merged data product with adjustments applied to minimize bias. These adjustments were derived by comparing the data from the 106 new cruises with the data from the 840 quality-controlled cruises of the GLODAPv2.2019 data product. They correct for errors related to measurement, calibration, and data handling practices, while taking into account any known or likely time trends or variations in the variables evaluated. The compiled and adjusted data product is believed to be consistent to better than 0.005 in salinity, 1 % in oxygen, 2 % in nitrate, 2 % in silicate, 2 % in phosphate, 4 μmol kg−1 in dissolved inorganic carbon, 4 μmol kg−1 in total alkalinity, 0.01–0.02, depending on region, in pH, and 5 % in the halogenated transient tracers. The other variables included in the compilation, such as isotopic tracers and discrete fCO2 were not subjected to bias comparison or adjustments. The original data, their documentation and doi codes are available at the Ocean Carbon Data System of NOAA NCEI (https://www.nodc.noaa.gov/ocads/oceans/GLODAPv2_2020/, last access: 22 June 2020). This site also provides access to the merged data product, which is provided as a single global file and as four regional ones – the Arctic, Atlantic, Indian, and Pacific oceans – under https://doi.org/10.25921/2c8h-sa89 (Olsen et al., 2020). The bias corrected product files also include significant ancillary and approximated data. These were obtained by interpolation of, or calculation from, measured data. This living data update documents the GLODAPv2.2020 methods and provides a broad overview of the secondary quality control procedures and results.

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