Embodiments of nanoelectronic sensors are described, including sensors for detecting analytes inorganic gases, organic vapors, biomolecules, viruses and the like. The method includes preparing a reference sample to have a stable work function, measuring a voltage of the sample using a non-contact voltage sensor, and determining a work function correction factor of the sensor from the measured voltage. At point-of-exit an exit reader determines if the tagged item is allowed to leave the facility by verifying the ownership code and the code or ticket.