Microscale Absorption Procedure for Simple and Rapid Gas-Liquid Extraction and Its Application to the Determination of Nitrogen Dioxide in the Atmosphere Coupled with Microflow Injection Analysis

摘要

A simple and miniaturized flow-through gas absorbing unit (GAU) using a small volume of an absorbing solution (0.5 mL) was developed and applied to teh determination of nitrogen dioxide (NO_2) in the atmosphere.The measuring method was coupled with a microflow injection analysis system (#mu#FIA) for a small sample size consumption.The absorption efficiency of a small sample size consumption.The absorption efficiency of NO_2 in the GAU was improved by packing hydrophobic poly(tetrafluoroethylene) (PTFE) particles in teh unit,and by using a triethanolamine aqueous solution (TEA,2 g/L) as an absorbing solution: absorption efficiency was increased up to more than 95%.THe absorbed NO_2 was converted to NO_3~- and NO_2~-.The molar ratio was ascertained to be 1:1 by measuring teh concentrations of NO_2~- and NO_3~- in the absorbing solution using #mu#FIA.Nitrogen dioxide at concentrations above 10 ppb in the atmosphere could be determined by teh proposed method