Method for improving the sensitivity of online detection of ammonia in ammonia-containing gas

By using photoionization ion mobility spectrometry to generate hydrated ammonia ions in the reaction zone and convert them into Ac2NH4+ in the migration zone, the problem of insufficient sensitivity and humidity interference in the detection of low concentration ammonia in the existing technology is solved, and efficient and low-cost ammonia detection is achieved.

CN117470943BActive Publication Date: 2026-06-12DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
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Patent Information

Application Number
CN202210869401.5
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2022-07-22
Publication Date
2026-06-12
Estimated Expiration
2042-07-22

AI Technical Summary

Technical Problem

Existing ammonia detection technologies struggle to achieve highly specific and sensitive online detection of low concentrations of ammonia in complex matrices, and are easily affected by sample humidity, lacking stable and accurate real-time analysis methods.

Method used

The photoionization ion mobility spectrometry technique is employed to generate hydrated ammonia ions by using a high-humidity gas in the reaction zone, and then converting them to Ac2NH4+ under dry conditions in the migration zone. A acetone reagent molecule undergoes a highly selective molecular substitution reaction with ammonia molecules to generate a stable product ion peak, eliminating humidity interference and improving detection sensitivity.

Benefits of technology

It achieves efficient, specific, and highly sensitive detection of low concentrations of ammonia, is simple to operate, low in cost, and is suitable for the detection of trace amounts of ammonia in exhaled breath, eliminating the influence of humidity on the detection.

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Abstract

The application provides a method for improving the sensitivity of ammonia online detection in ammonia-containing gas. The method replaces the dry compensation gas in the reaction zone with high-humidity gas, so that the water concentration in the reaction zone is much higher than the concentration of reagent molecules, i.e. acetone, to generate hydrated ammonia ions, thereby increasing the reactivity of reagent ions and sample ammonia gas molecules. Under the action of drift gas, the migration zone is kept dry and high-concentration acetone, so that the generated hydrated ammonia ions are converted into Ac2NH4 + again during the migration in the migration zone. The product ions are highly stable during the migration in the migration tube. In the whole process of the application, water molecules participate in the reaction, which improves the sensitivity of ammonia detection to a certain extent. The finally generated product ions remain unchanged, and a single ammonia product peak is presented on the ion mobility spectrum. Meanwhile, the introduced humidification gas keeps the reaction zone at saturated humidity, and the humidity change of the sample gas does not affect the detection, thereby eliminating the influence of different sample humidity on the detection accuracy. The method is simple to operate and is suitable for the detection of trace ammonia in ammonia-containing gas.
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