Determination of NH3 gas by combination of nanosized LaCoO3 converter with chemiluminescence detector

Combination of a novel NH3 converter based on nanosized materials with chemiluminescence (CL) detector for the determination of NH3 gas was demonstrated in this paper. NH3 gas is oxidized on different nanosized catalysts to produce NOx, which can react with luminol to generate CL emission. Eight nanosized materials were investigated as catalyst, and CL was detected from seven of them. The nanosized LaCoO3 was chosen as the catalyst for preparing the converter because of its higher activity than others. Under the optimized conditions, the linear range of CL intensity versus concentration of NH3 gas is 0.04–10 ppm (r=0.9951, n=14) with the detection limit of 0.014 ppm. The method offers advantages of long lifetime of the converter, fast response and high selectivity to NH3. There was no response while the foreign substances, such as hydrogen, oxygen, nitrogen, formaldehyde, acetone and gasoline passing through the CL detection system, and the interference of CCl4, ethanol, ethylene and toluene was insignificant.