Related Experiment Video
Updated: Feb 1, 2026

Analyzing the Photo-oxidation of 2-propanol at Indoor Air Level Concentrations Using Field Asymmetric Ion Mobility Spectrometry
Published on: June 14, 2018
[Determination of trace ammonia in indoor air by ninhydrin spectrophotometry]
Yang Li1, Yi Liu, Cheng-jun Sun
1Department of Sanitary Technology, West China School of Public Health, Sichuan University, Chengdu 610041, China.
Objective:
To develop a new spectrophotometric method to detect trace ammonia in indoor air.
Methods:
Ammonia in the air was absorbed by 0.01 mol/L sulfuric acid in a bubbling absorption tube. With 95 degrees C of water bath and pH 5.5-6.0 of buffer solution of acetic acid-sodium acetate, the ammonium in the solution reacted with ninhydrin at the presence of ascorbic acid to form a royal purple product which has a maximum absorbance at 568 nm.
Results:
This method produced a linear range of 0-8 microg/10 mL. The detection limit was 0.06 mg/m3. The recoveries of the method ranged from 96.2% to 102.3%, with 2.8%-6.8% of relative standard deviations.
Conclusion:
The method is simple, rapid and safe. The common coexisting substances in the air do not interfere with the determination. The precision and accuracy can satisfy the requirements of the determination of trace ammonia in indoor air.
Related Concept Videos
Spectrophotometry: Introduction
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
Preparation of Amines: Alkylation of Ammonia and Amines
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Air-entraining Agents
Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia
When dissolved in liquid ammonia, an alkali metal, such as sodium,...
Effects of Air-entrainment in Concrete
Measurement of Air Content in Concrete
The pressure method,...

