A chemical sensor is disclosed. The chemical sensor is an electronic device including in specific embodiments a first transistor and a second transistor. The first transistor includes a semiconducting layer made of a first semiconductor and carbon nanotubes. The second transistor includes a semiconducting layer made of a second semiconductor, and does not contain carbon nanotubes. The two transistors vary in their response to chemical compounds, and the differing response can be used to determine the identity of certain chemical compounds. The chemical sensor can be useful as a disposable sensor for explosive compounds such as trinitrotoluene (TNT). The electronic device is used in conjunction with an analyzer that processes information generated by the electronic device.