We have investigated the sensing properties of the carbon nanotubes deposited onto a cadmium arachidate buffered multilayer by acoustic sensors -- SAW and QCM -- and a reflectometric sensor system based on optical fiber for purposes of chemical detection of volatile organic compound (VOCs), at room temperature. The carbon nanotubes have been deposited by the molecular engineering Langmuir-Blodgett (L-B) technique onto a buffer multilayer of cadmium arachidate prepared monolayer-by-monolayer using the L-B technique as well. The sensing multilayered material has been prepared both onto a standard silica optical fiber configured in a reflectometer sensor system and onto acoustic sensors -- SAW and QCM -- configured as oscillators. The acoustic sensors and the optical sensor have been exposed simultaneously, in the same test chamber, towards different VOCs such as ethanol, methanol, iso-propanol, acetone, ethylacetate, toluene with different vapor pressures for comparing the sensitivity of the coating onto the different kinds of acoustic and optical transducers. Moreover, for the same type of transducer, acoustic or optical, the effect of carbon nanotubes onto the gas sensitivity is remarkably higher in all investigated cases.