Portable impedance based chemical sensor

A computerized system of sensing a target analyte in an environment, the system comprising:

• a computer comprising a processor and computerized memory storing software that controls a sensing circuit comprising an AC energy source and at least one sensing output terminal;
• a sensing material connected to the AC energy source and further connected to a respective sensing output terminal of the sensing circuit, wherein the AC energy source directs a plurality of alternating inputs at respective frequencies across the sensing material and induces a series of outputs at the respective frequencies from the sensing output terminal;
• an impedance detection circuit receiving the series of outputs, assigning a corresponding series of impedance values to the sensing material at the respective frequencies, and transmitting the impedance values and the respective frequencies to the computer;
• and
• a computerized software module stored in the memory that identifies a change in the series of impedance values that is greater than a predetermined threshold value and indicates a presence of the target analyte at the sensing material.

A method of sensing a target analyte in an environment, the method comprising:

• selecting a sensing material having a consistent impedance response in an exposed state in the presence of environmental agents other than a target analyte;
• applying an alternating energy input to the sensing material and inducing an alternating energy output from the sensing material;
• tracking an impedance response of the sensing material across a frequency spectrum of the alternating energy inputs;
• isolating frequency induced impedance changes across the sensing material from the consistent impedance response due to the environmental agents;
• identifying a magnitude of the frequency induced impedance changes across the frequency spectrum, and
• for impedance changes greater than a predetermined threshold across a subset of frequencies in the frequency spectrum, determining the presence of the target analyte at the sensing material.