Chemiluminescence determination of nitrogen oxide in air with a sequential injection method

A chemiluminescence (CL) method coupled to sequential injection was described for the determination of trace amount of nitrogen oxide in air. The flow cell and holding coil was combined in which the flow cell was as a part of holding coil, which make it easy to track CL reaction for the sequential injection analytical system. Triehanolamine (TEA) solution was used to absorb nitrogen dioxide in air and then converted into nitrite. Nitride reacts with hydrogen peroxide to form peroxynitrous acid in sulfuric acid medium, which is subsequently quenched into peroxynitrite in basic solution and accompanied with CL reaction. Uranine and ethyldimethylcetylammonium bromide were used to enhance the CL intensity during the decomposition of peroxynitrite. The detection limit (3σ) of 1 × 10−7 M was obtained for 50 μl sample. Nitrogen oxide can be determined in the linear range of 1 × 10−7-1 × 10−4 M with correlation coefficient of 0.9999. The relative standard deviation (R.S.D.) for 11 repeated measurements of 1 × 10−5 M NO2− was 2.7%. The sampling frequency was 80 samples/h, and the recoveries were 85-104%.