Absorption, concentration and determination of trace amounts of air pollutants by flow injection method coupled with a chromatomembrane cell system: application to nitrogen dioxide determination

The concentration distribution of an analyte in a chromatomembrane cell (CMC) was examined by using various air samples of different air pollutant (NO2) concentrations and volumes, and the results obtained could be explained by a proposed principle of the concentration distribution of the analyte in the CMC. This principle was for the first time proved experimentally in the present study. On-line preconcentration and continuous determination of the air pollutant (NO2) in air samples were realized by coupling a three-hole CMC with a flow injection analysis (FIA) system, where a triethanolamine (TEA) aqueous solution (2 g l−1) was used as an absorbing solution for NO2 in the air samples. A calibration method with standard nitrite aqueous solutions was developed for the determination of NO2 in the air samples. Concentrations of NO2 in indoor air and its diluted air samples were determined by the proposed CMC/FIA method. The volume of air sample necessary for the measurement was decreased to only 5 ml. The measuring time for one sample was about 5–6 min even when a 20 ml air sample was used.