Amperometic microsensor for measurement of gaseous and dissolved CO2

SENSORS AND ACTUATORS B-CHEMICAL

卷:283

Article

Revsbech, Niels Peter¹  Garcia-Robledo, Emilio^1,2  Sveegaard, Steffen^3,4,5  Andersen, Mikkel Holmen³  Gothelf, Kurt Vesterager^4,5  Larsen, Lars Hauer³ 

[1] Aarhus Univ, Dept Biosci, Ctr Water Technol, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark

[2] Univ Cadiz, Dept Biol, Campus Puerto Real, Cadiz 11510, Spain

[3] Unisense AS, Tueager 1, DK-8200 Aarhus N, Denmark

[4] Aarhus Univ, INANO, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark

[5] Aarhus Univ, Dept Chem, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark

关键词: Ionic liquid;    Carbon dioxide reduction;    Microelectrode;    Clark electrode;    Oxygen scavenger;   

DOI  :  10.1016/j.snb.2018.12.038

来源: Elsevier

【 摘 要 】

A simple method to measure dissolved CO2 at a microscale would be beneficial for many scientific and medical applications. A simple amperometic microsensor for CO2 with a 20-100 mu m wide tip was developed by placing a layer of acidic O-2 trap solution containing Cr2+ in front of a Clark-type electrochemical sensor. The Clark-type sensor contains a Ag cathode in an ionic liquid, and also a Ag guard cathode behind the sensing cathode to prevent interference from reducible contaminants in the ionic liquid. The constructed sensors exhibited linear response over relatively large intervals of CO2 partial pressure, but for CO2 partial pressures of < 20 Pa the response was only about 60% of that observed at 20-1000 Pa. The slope of the calibration curve at 2-6 kPa was about 80% of the slope from 0 to 1 kPa. A high baseline signal caused by water diffusing through the membrane into the ionic liquid was avoided by making very conical sensors so that the water concentration around the cathode was kept low by diffusional transport into the bulk reservoir of ionic liquid, but elevated zero currents by a factor of about two was often observed for sensors more than 1 month old. The lifetime of the sensor by continuous operation can be more than 4 months, but with a slow decrease in sensitivity that may be caused by lower membrane permeability. Use of the sensor was demonstrated by measuring CO2 dynamics in the thallus of a red algae along with variations in O-2 and pH.

【 授权许可】

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