Chemical sensor using eddy current or resonant electromagnetic circuit detection

A chemical sensing apparatus for measuring analytes comprising:

• a resistance inductance capacitance probe;
• an electromagnetic transducer connected to the probe;
• a chemically sensitive material on or adjacent said eddy current probe;
• means connected to said probe for inducing current in said material;
• and
• detector means for detecting a change in impedance or resonant frequency of the probe through induced eddy currents in the material indicative of the analyte to be sensed.

Chemical sensor apparatus for measuring chemical analytes comprising:

• an electrically conductive or magnetically permeable material;
• a contact area for contacting a chemical analyte with the material which changes the electrical conductivity or magnetic permeability of the material;
• a probe having a circuit adjacent the material;
• an excitation frequency source connected to the probe;
• a sensor circuit connected to the probe for sensing change in circuit parameters of the probe, the sensor circuit further comprising a second frequency source;
• and
• a signal processor connected to the sensor circuit and an output connected to the processor for indicating the change in electrical conductivity or magnetic permeability of the chemical analyte sensed.

A chemical sensor apparatus for chemical analytes comprising:

• a film of electrically conductive material for undergoing a change in conductivity or magnetic permeability when contacted by a chemical analyte;
• a circuit;
• a probe positioned adjacent the film;
• an electrical conductor in the probe connected to the circuit and being in electrical isolation from the film;
• a source of frequency connected to the circuit;
• and
• a sensor connected to the circuit for detecting changes in circuit parameters according to a chemical analyte on the film.