Aarhus University Centre for Water Technology, Department of Bioscience, Ny Munkegade 114, 8000, Aarhus C, Denmark.
Department of Earth System Science, Stanford University, CA, 94305, Stanford, USA.
Anal Chim Acta. 2020 Mar 8;1101:135-140. doi: 10.1016/j.aca.2019.12.019. Epub 2019 Dec 17.
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 NO 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 NO 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 NO 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 NO 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.
一氧化二氮是一种重要的温室气体，因此需要灵敏的技术来研究其在与大气平衡浓度（20°C 时水中为 9.6 nM）附近的环境中的分布。在这里，我们提出了一种能够在纳摩尔范围内定量检测 NO 的电化学传感器。该传感器的原理依赖于置于测量阴极前面的前置保护阴极。该阴极用于周期性地阻挡 NO 流向测量阴极的通量，从而在信号中产生幅度。该信号幅度不受基线电流漂移的影响，并且可以以非常高的分辨率读取，从而为新构建的传感器提供 2 nM NO 的灵敏度。通过将前置保护阴极置于消耗氧气的电解质中，可以防止氧气的干扰。该传感器通过测量东热带北太平洋（ETNP）墨西哥海岸外氧气最小区的 120 米深处的 NO 剖面进行了现场测试。
