On-line measuring system and measuring method for concentration of nitrous acid and nitrous acid

Abstract

The invention discloses an on-line measuring system and a measuring method for concentration of nitrous acid and nitrous acid. The system comprises an external sample feeding unit, a liquid phase chemical conversion unit and an optical absorption detection unit which are connected in sequence, wherein the external sample feeding unit is used for feeding a sample of a nitrogen-containing compound; the liquid phase chemical conversion unit is used for absorbing and converting the liquid phase chemical conversion unit from the external sample feeding unit into nitrite; and the optical absorption detection unit is used for converting the nitrite from the liquid phase chemical conversion unit into an ultraviolet-visible absorbent material, and used for implementing optical detection. By adopting the system, simultaneous measurement of the nitrous acid and the nitric acid can be achieved, and furthermore interference of other gaseous phase substances can be eliminated through parallel channels. By adopting the system, trace detection on the nitrous acid and the nitric acid in the atmosphere can be achieved, and trace detection on the nitrous acid and the nitric acid in water bodies is also achieved, the detection sensitivity is greater than 10pptv and 0.03mu g / L, the response time is less than 3-5 minutes, and the system can be applied to atmospheric environments, water body environment monitoring, experimental scientific research and the like.

Description

technical field [0001] The invention relates to the field of atmospheric environment detection and experimental scientific research, in particular to a real-time on-line measurement system and method for the concentration of nitrous acid and nitric acid. Background technique [0002] Nitrous acid (HONO) is a trace nitrogen-containing substance in the atmosphere, and it is also a typical secondary pollutant. Its concentration can be used as an indicator to directly reflect the degree of urban air pollution. nitric acid (HNO 3 ) is an important oxidation product of nitrogen oxides in the atmosphere, which can be generated by free radical reactions, and can also be produced by the hydrolysis of nitrogen pentoxide, which affects the global environment through dry and wet deposition while affecting the atmospheric nitrogen cycle. With the frequent occurrence of urban smog events, the research on gaseous nitrous acid and nitric acid has increasingly become a hot topic. However, d...

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Problems solved by technology

However, most of the above methods face some limitations. On the one hand, there are many interfering gases, which may lead to inaccurate measured HONO concentration; on the other hand, the detection limit is high, and the measurement of HONO with low concentration during the day cannot meet the requirements.

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