Determination of nitrogen oxide in air by sequential injection analysis with chemiluminescence detection

Nitride reacts with hydrogen peroxide to form peroxynitrous acid in sulfuric acid medium,which is an unstable state in acid medium and subsequently was quenched into peroxynitrite in basic solution.Based on this,a sequential injection chemiluminescence method for the determination of trace amounts of nitrogen oxide in air was established.During the composition of peroxynitrite the chemiluminescence intensity was enhanced with the presence of uranin and cetyl trimethyl ammonium bromide(CTMAB). The product from the reaction between nitrogen dioxide and triethanolamine was used as an absorbing solution for NO_2 in the conversion of NO_2 to nitrite. The reaction coil(flow cell) and holding coil were combined as a new sampling means.The detection limit of NO_2 is 1×10~(-7) mol/L for 50 μL sample and the sampling frequency is 80 samples per hour.The linear range of the calibration curve is from 1×10~(-7) to 1×10~(-4) mol/L.The relative standard deviation for 1×10~(-5) mol/L NO_2 is 2.7% with the recovery of 85%-104%.