Construction of a sensor for determination of ammonia and aliphatic amines using polyvinylpyrrolidone coated quartz crystal microbalance

Polyvinylpyrrolidone (PVP) modified quartz crystal microbalance (QCM) has been used for determination of ammonia and a number of short chain primary aliphatic amines in atmospheric media. A solution casting method was used for modification of quartz crystal with a thin layer of PVP. Determination was based on frequency shifts due to adsorption of the compounds at the surface of the modified electrode. The frequency shifts were found to be linear against the concentration of analyte in the range between 0.5 and 30 mg l−1 with correlation coefficients of above 0.9903. The sensitivity factors in the range of 7.5–48.2 Hz/mg l−1 was obtained. A storage period of over 5 months proved no loss in sensitivity and performance. Among some possible interference tested, no major interference was involved in the performance of the sensor except for water vapor, which may be resolved by drying the samples prior to injection.