A bioreceptor known to bind to volatile organic compounds (VOCs) – olfactory receptors, odorant binding proteins or VOC affinity peptides – is selected for immobilization. Surface immobilization can be made through different methods including affinity, covalent spacers, and thiol-based chemistry. The biosensor is then applied in a signal transducing system which may be, for example, electrical, gravimetric, or optical. The collected data is finally processed to yield qualitative or quantitative information about target VOCs.