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| Titel |
A degassing instrument for analysing CO2 dissolved in natural water |
| VerfasserIn |
Brian Durham, Christian Pfrang |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152662
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| Publikation (Nr.) |
 EGU/EGU2017-17527.pdf |
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| Zusammenfassung |
| Arising from our EGU 2017 presentation (http://meetingorganizer.copernicus.org/EGU2016/posters/20564,
X2 352), interest has been expressed in its application to the analysis of the hydrocarbonate
ion [HCO3−] in atmospheric water.
Arising from the historic difficulty in analysing the aqueous [HCO3−] ion (‘it is in all our
reagents’, pers. comm. UK laboratory) the classic determination has been to measure a suite
of other anions and cations including [H+] via pH, and to treat the balance of negative charge
as a measure of [HCO3−].
From this balance, dissolved CO2 can be inferred via the dissociation constant as
published for pure water.
CO2 + H2O ⇓♢[HCO3−] + [H+] K1 = 4.2 x 10−7
Our EGU 2016 presentation sought to determine how the ionic environment in 263 UK
rain samples can influence the above equilibrium, which is work in progress. In the mean
time we have received the following expression of interest from an atmospheric science
advisory group.
…….. is very interested in the role of H-carbonate in the ion balance of precipitation.
They have had some discussions recently about the best approach to infer H-carbonate
currently discussing the possibility of sending you samples from other locations for
analysis.
We have duly offered to use our degassing instrument to corroborate current analyses in a
batch of ‘blind’ samples, and to provide a design for a basic degasser that water quality
laboratories could evaluate in house. This paper therefore presents a circuit for
degassing CO2 from water samples irrespective of whether in atmospheric equilibrium
or supersaturated, including a prototype 4-way distribution and collection valve
which it is hoped will make the analysis intuitive and therefore open to automation. |
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