Typical interdigital capacitive sensors (IDC-S), are made of an 'inert' substrate over which two planar interdigital electrodes are deposited. One chemical sensitive layer is then deposited over the electrodes. The sensitive layer can be chosen according to its partition coefficient to a given organic volatile. The change in capacitance of these sensors by the sorption of the analyte molecules depends on the changes in the dielectric permittivity and on swelling of the polymer layer. These types of sensors enable a wide choice of polymeric sensitive layers, which can be especially chosen for the case studied. If several sensors with different sensitive layers are used to make a sensor array it is then possible to evaluate complex gas samples. Two different polymeric layers are studied, polydimethylsiloxane (PDMS) and polyocthylmethylsiloxane (POMS) for different volatile organic compounds in aqueous solutions.