1. Amperometric sensor for nanomolar nitrous oxide analysis
- Author
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Colette L. Kelly, Karen L. Casciotti, Bess B. Ward, Niels Peter Revsbech, and Lars Riis Damgaard
- Subjects
Oxygen minimum zone ,Microsensor ,Diphenylphosphine ,02 engineering and technology ,Electrolyte ,01 natural sciences ,Biochemistry ,Signal ,Analytical Chemistry ,law.invention ,Atmosphere ,chemistry.chemical_compound ,law ,Environmental Chemistry ,Spectroscopy ,Nitrous oxide ,business.industry ,010401 analytical chemistry ,Front (oceanography) ,STOX ,021001 nanoscience & nanotechnology ,Cathode ,0104 chemical sciences ,Electrochemical gas sensor ,chemistry ,Optoelectronics ,Oxygen scavenger ,Current (fluid) ,0210 nano-technology ,business - Abstract
Nitrous oxide is an important greenhouse gas and there is a need for sensitive techniques to study its distribution in the environment at concentrations near equilibrium with the atmosphere (9.6 nM in water at 20 °C). Here we present an electrochemical sensor that can quantify N2O in the nanomolar range. The sensor principle relies on a front guard cathode placed in front of the measuring cathode. This cathode is used to periodically block the flux of N2O towards the measuring cathode, thereby creating an amplitude in the signal. This signal amplitude is unaffected by drift in the baseline current and can be read at very high resolution, resulting in a sensitivity of 2 nM N2O for newly constructed sensors. Interference from oxygen is prevented by placing the front guard cathode in oxygen-consuming electrolyte. The sensor was field tested by measuring an N2O profile to a depth of 120 m in the oxygen minimum zone of the Eastern Tropical North Pacific Ocean (ETNP) off the coast of Mexico.
- Published
- 2020