Abstract: In this paper, a micromethod for the determination of carbon and hydrogen in organo-metallic compounds has been reported, 3-5 mg of sample was covered with 10 mg of freshly prepared Co₃O₄ in platinum boat and burned over a catalyst of products of thermal decomposition of silver permanganate under a current of oxygen (25ml/min. ) at 500-550°C. The combustion took about 10 minutes. The data of determination of a series of standard organo-metallic compounds showed that the absolute deviation of this method was within ±0.3%. As a result of low combustion temperature, the duration of the silica combustion tubes was much increased. The properties of MnO₂ reagents for absorbing nitrogen oxides prepared by various methods were compared and the procedure for preparing the most effective reagent was described.