DETERMINATION OF NH3 IN PYROLYSIS GASES BY AMMONIA SELECTIVE ELECTRODE

The suitability of ion-selective electrode for the determination of am monia in pyrolysis gases of fossil fuels was studied. The ammonia was absorbed into acidic solution and two kinds of determination methods w ere carried out. The ammonia was either measured directly from the aci d solution, or ammonia was first released into the gas phase and then determined (air gap method) by the ammonia selective electrode. The el ectrode functioned well in both cases, but the linear calibration rang e was rather narrow, slightly more than one tenfold. The quantitative detection limit in the water phase was 5 x 10(-6)M (0.085 ppm) NH3 and in gas phase operation solutions above 5 x 10(-4)M (8.5 ppm) NH3 it W aS possible to measure quantitatively. The applications were carried o ut with Finnish energy peat samples and a coal sample.