Piezoresonance sensor for ammonia with polymaleic acid as the sensitive coating

Results of the study of a piezoresonance sensor with polymaleic acid as the sensitive coating for the determination of the concentration of ammonia in air are presented. The influence of the mass of the polymer coating, the R ow rate of the carrier gas, and relative humidity on the performance charac teristics of the sensor was studied. The mechanism of the interaction of am monia with the sorbent in the presence of water vapors is proposed based on experimental data and quantum chemical calculation. It is found that the s ensor exhibits high selectivity for ammonia in the presence of vapors of sa turated and aromatic hydrocarbons. The detection limit for ammonia at the h umidity 45-55% is 0.04 mg/m(3), which makes it possible to determine ammoni a at a level of the maximum permissible concentration for inhabited areas; the concentration characteristic of the sensor is linear in the concentrati on range 0.04-40 mg/m(3).