The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

Damian Moran; Bjørn Tirsgård; John Fleng Steffensen

doi:10.1016/j.aquaeng.2010.07.003

The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

Damian Moran, Bjørn Tirsgård, John Fleng Steffensen

Marine Biological Section

12 Citationer (Scopus)

Abstract

The OxyGuard CO(2) Analyzer is a novel meter that can directly measure aqueous CO(2) gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO(2) is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We undertook to independently validate the precision and utility of this meter. Water flow over the probe membrane was a key determinant of the reaction time. At water velocities of >= 30 cm s(-1) the time to 99% span was 6-7 min, while at 0 cm s(-1) it was 55-60 min. Temperature and CO(2(aq)) concentration did not appreciably affect reaction time. The meter had a precision of +/- 0.5 mg L(-1) CO(2(aq)), and high linearity (correlation 0.99-1.01) above 1 mg L(-1) in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO(2) levels, but will be useful in situations where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings. (C) 2010 Elsevier B.V. All rights reserved.

Originalsprog	Engelsk
Tidsskrift	Aquacultural Engineering
Vol/bind	43
Udgave nummer	3
Sider (fra-til)	101-107
Antal sider	7
ISSN	0144-8609
DOI	https://doi.org/10.1016/j.aquaeng.2010.07.003
Status	Udgivet - 1 nov. 2010

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10.1016/j.aquaeng.2010.07.003

Citationsformater

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title = "The accuracy and limitations of a new meter used to measure aqueous carbon dioxide",

abstract = "The OxyGuard CO2 Analyzer is a novel meter that can directly measure aqueous CO2 gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO2 is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We undertook to independently validate the precision and utility of this meter. Water flow over the probe membrane was a key determinant of the reaction time. At water velocities of ≥30cms-1 the time to 99% span was 6-7min, while at 0cms-1 it was 55-60min. Temperature and CO2(aq) concentration did not appreciably affect reaction time. The meter had a precision of ±0.5mgL-1 CO2(aq), and high linearity (correlation 0.99-1.01) above 1mgL-1 in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO2 levels, but will be useful in situations where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings.",

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T1 - The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

AU - Moran, Damian

AU - Tirsgård, Bjørn

AU - Steffensen, John Fleng

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N2 - The OxyGuard CO2 Analyzer is a novel meter that can directly measure aqueous CO2 gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO2 is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We undertook to independently validate the precision and utility of this meter. Water flow over the probe membrane was a key determinant of the reaction time. At water velocities of ≥30cms-1 the time to 99% span was 6-7min, while at 0cms-1 it was 55-60min. Temperature and CO2(aq) concentration did not appreciably affect reaction time. The meter had a precision of ±0.5mgL-1 CO2(aq), and high linearity (correlation 0.99-1.01) above 1mgL-1 in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO2 levels, but will be useful in situations where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings.

AB - The OxyGuard CO2 Analyzer is a novel meter that can directly measure aqueous CO2 gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO2 is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We undertook to independently validate the precision and utility of this meter. Water flow over the probe membrane was a key determinant of the reaction time. At water velocities of ≥30cms-1 the time to 99% span was 6-7min, while at 0cms-1 it was 55-60min. Temperature and CO2(aq) concentration did not appreciably affect reaction time. The meter had a precision of ±0.5mgL-1 CO2(aq), and high linearity (correlation 0.99-1.01) above 1mgL-1 in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO2 levels, but will be useful in situations where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings.

U2 - 10.1016/j.aquaeng.2010.07.003

DO - 10.1016/j.aquaeng.2010.07.003

M3 - Journal article

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VL - 43

SP - 101

EP - 107

JO - Aquacultural Engineering

JF - Aquacultural Engineering

IS - 3

ER -

The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

Abstract

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