The application of the chromatomembrane cell for the absorptive sampling of nitrogen dioxide followed by continuous determination of nitrite using a micro-flow injection system

A simple and rapid procedure for NO2 determination in air was developed by coupling the chromatomembrane method with a micro-FIA system. A three-hole chromatomembrane cell was successfully applied to on-line preconcentration of atmospheric NO2 in a solution of 2 g l−1 triethanolamine (TEA) as an aqueous absorbing solution. The lowest volume of an air sample necessary for the measurement was 5, and 0.02 ml portions of the solution containing the absorbed NO2 (NO2− and NO3−) were supplied to a micro-FIA system being the succeeding component of the proposed analyzer. The amounts of NO2− in the absorbing solution were measured by a diazotization-coupling reaction with sulfanilamide and N-(1-naphthyl) ethylenediamine, and referred to the concentration of NO2 in the air sample. The NO2 content of indoor air was determined to be 43±1 ppb using 20 ml of air, and the R.S.D. was ±1.89%.