The sensing properties of Langmuir-Blodgett (LB) films consisting of tangled Single-Walled Carbon Nanotubes (SWCNTs) used as sensitive nanomaterials for Volatile Organic Compounds (VOCs) detection have been investigated by using Quartz Crystal Microbalance (QCM) 10 MHz AT-cut quartz resonators, and standard Silica Optical Fiber SOF) based on light reflectometry at a wavelength of 1310 nm. The proposed detection techniques are focused on two key parameters in the gas sensing applications as mass change and complex refractive index change induced by gas molecules adsorption. Highly sensitive, repeatable and very fast responses of SWCNTs sensors to ethanol and ethylacetate, with concentrations in the range 10-500 ppm, have been observed. A good inter-relationship has been found between the two different transducers, showing a good correlation of the sensing mechanisms based on the change in the mass and optical properties of the chemosensitive nanomaterial for QCM and SOF sensors, respectively.