Larsen L H, Kjær T, Revsbech N P
Department of Microbial Ecology, Institute of Biological Sciences, University of Aarhus, Bd. 540, DK-8000 Aarhus C, Denmark.
Anal Chem. 1997 Sep 1;69(17):3527-31. doi: 10.1021/ac9700890.
A biosensor for NO(3)(-) containing immobilized dentrifying bacteria and a reservoir of liquid growth medium for the bacteria was constructed. The bacteria did not have a N(2)O reductase and therefore reduced NO(3)(-) to N(2)O, which was then subsequently quantified by a built-in electrochemical transducer for N(2)O. The only agents interfering with the determination of NO(3)(-) were NO(2)(-) and N(2)O. The sensitivity for NO(2)(-) was identical to the one for NO(3)(-) whereas the sensitivity for N(2)O was 2.4 times higher than for NO(3)(-). Diffusive supply of electron donors to the bacteria from the built-in reservoir of growth medium ensured that the biosensor could work for 2-4 days. The tip diameter was down to 20 μm, and the sensors exhibited perfectly linear responses to nitrate in both freshwater and seawater. The detection limit was ∼1 μM. The 90% response time to changes in NO(3)(-) concentration was from 15 to 60 s at room temperature and about twice that at 6 °C, which was the lowest temperature for successful operation. The new NO(3)(-) biosensor is a very useful tool for the study of nitrogen metabolism in nature.
构建了一种包含固定化反硝化细菌的硝酸根生物传感器以及用于细菌的液体生长培养基储存器。这些细菌没有一氧化二氮还原酶，因此将硝酸根还原为一氧化二氮，然后通过内置的用于检测一氧化二氮的电化学传感器对其进行定量。唯一干扰硝酸根测定的物质是亚硝酸根和一氧化二氮。对亚硝酸根的灵敏度与对硝酸根的灵敏度相同，而对一氧化二氮的灵敏度比对硝酸根的灵敏度高2.4倍。从内置的生长培养基储存器向细菌扩散供应电子供体，确保生物传感器能够工作2至4天。尖端直径低至20μm，并且该传感器对淡水和海水中的硝酸盐均表现出完美的线性响应。检测限约为1μM。在室温下，对硝酸根浓度变化的90%响应时间为15至60秒，在6°C（成功运行的最低温度）时约为室温下的两倍。这种新型硝酸根生物传感器是研究自然界中氮代谢的非常有用的工具。
