Abstract: Characteristics of separation on 2 kinds of cation chromatographic column,i.e.,the Dionex IonPac CS12A and IonPac CS16,were studied comparatively,and these 2 columns were made feasible to be used in combination with the methods of passive sampling and active sampling under optimum chromatographic conditions.Considering the incomplete ionization of the weakly alkaline NH+4-ion,a procedure for IC determination of ammonia in indoor air of museum was proposed.Two standard curves,one for low concentrations (0.01-0.50 mg·L-1) and the other for high concentrations (0.50-5.00 mg·L-1) of NH3,were prepared.Value of detection limit (3S/N) of 0.9 μg·L-1 was obtained in case of passive sampling,and of 1.6 μg·L-1 in case of active sampling.Values of recovery found by standard addition method were in the range from 97.2%-105.7% for passive sampling,and in the range of 102.8%-104.7% for active sampling.