Metal nanoparticles and nanostructured materials are attracting tremendous interests for their unique properties and potential applications in microelectronics, catalysis, and chemical sensors. This presentation focuses on the detection of volatile organic compounds (VOCs) using nanostructure-coated chemiresistor on piezoelectric sensors. We report here the preliminary results on comparison of FID detector and sensor array in the detection of VOCs. Our comparison is directed towards assessing sensitivity, resolution, selectivity and limit of detection. Selectivity, which has been a challenging area especially in a complex sensing environment, has been addressed by use of sensing arrays constructed from nanoparticle thin films and interdigitated microelectrodes. Implication of the preliminary results to the improvement of the sensor array will also be discussed.