On-line technique for preparingand measuring stable carbon isotopeof total dissolved inorganic carbonin water samples ( d13CTDIC)
Main Article Content
Abstract
A fast and completely automated procedure is proposed for the preparation and determination of d13C of total
inorganic carbon dissolved in water ( d13CTDIC). This method is based on the acidification of water samples transforming
the whole dissolved inorganic carbon species into CO2. Water samples are directly injected by syringe
into 5.9 ml vials with screw caps which have a pierciable rubber septum. An Analytical Precision «Carbonate
Prep System» was used both to flush pure helium into the vials and to automatically dispense a fixed amount of
H3PO4. Full-equilibrium conditions between produced CO2 and water are reached at a temperature of 70°C
(± 0.1°C) in less than 24 h. Carbon isotope ratios (13C/ 12C) were measured on an AP 2003 continuous flow mass
spectrometer, connected on-line with the injection system. The precision and reproducibility of the proposed
method was tested both on aqueous standard solutions prepared using Na2CO3 with d13C=-10.78 per mil versus
PDB (1 s= 0.08, n = 11), and at five different concentrations (2, 3, 4, 5 and 20 mmol/l) and on more than
thirty natural samples. Mean d13CTDIC on standard solution samples is ?10.89 < per mil versus PDB (1 s= 0.18,
n = 50), thus revealing both a good analytical precision and reproducibility. A comparison between average
d13CTDIC values on a quadruplicate set of natural samples and those obtained following the chemical and physical
stripping method highlights a good agreement between the two analytical methods.
inorganic carbon dissolved in water ( d13CTDIC). This method is based on the acidification of water samples transforming
the whole dissolved inorganic carbon species into CO2. Water samples are directly injected by syringe
into 5.9 ml vials with screw caps which have a pierciable rubber septum. An Analytical Precision «Carbonate
Prep System» was used both to flush pure helium into the vials and to automatically dispense a fixed amount of
H3PO4. Full-equilibrium conditions between produced CO2 and water are reached at a temperature of 70°C
(± 0.1°C) in less than 24 h. Carbon isotope ratios (13C/ 12C) were measured on an AP 2003 continuous flow mass
spectrometer, connected on-line with the injection system. The precision and reproducibility of the proposed
method was tested both on aqueous standard solutions prepared using Na2CO3 with d13C=-10.78 per mil versus
PDB (1 s= 0.08, n = 11), and at five different concentrations (2, 3, 4, 5 and 20 mmol/l) and on more than
thirty natural samples. Mean d13CTDIC on standard solution samples is ?10.89 < per mil versus PDB (1 s= 0.18,
n = 50), thus revealing both a good analytical precision and reproducibility. A comparison between average
d13CTDIC values on a quadruplicate set of natural samples and those obtained following the chemical and physical
stripping method highlights a good agreement between the two analytical methods.
Article Details
How to Cite
1.
Capasso G, Favara R, Grassa F, Inguaggiato S, Longo L. On-line technique for preparingand measuring stable carbon isotopeof total dissolved inorganic carbonin water samples ( d13CTDIC). Ann. Geophys. [Internet]. 2005Dec.25 [cited 2023Dec.2];48(1). Available from: https://www.annalsofgeophysics.eu/index.php/annals/article/view/3190
Issue
Section
OLD
Open-Access License
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.
In most cases, appropriate attribution can be provided by simply citing the original article.
If the item you plan to reuse is not part of a published article (e.g., a featured issue image), then please indicate the originator of the work, and the volume, issue, and date of the journal in which the item appeared. For any reuse or redistribution of a work, you must also make clear the license terms under which the work was published.
This broad license was developed to facilitate open access to, and free use of, original works of all types. Applying this standard license to your own work will ensure your right to make your work freely and openly available. For queries about the license, please contact ann.geophys@ingv.it.