Systems and methods for detecting change in species in an environment

A method for determining a concentration of an analyte, the method comprising:

• applying an alternating voltage to a first electrode and a second electrode of a capacitive sensor in the presence of the analyte;
• measuring a first capacitance of the capacitive sensor in presence of the analyte;
• irradiating the analyte for a predetermined time period at a discrete frequency within an infrared frequency range;
• measuring a second capacitance of the capacitive sensor at the end of the predetermined time period;
• determining a difference between the first and second capacitances;
• and
• determining the concentration of the analyte based on the difference.

A method for determining a composition and concentration of an analyte, the method comprising:

• applying an alternating signal to a first electrode and a second electrode of a sensor in the presence of the analyte;
• measuring a first capacitance of the sensor in presence of the analyte;
• irradiating the analyte for a predetermined time period at a discrete frequency within a predetermined frequency range;
• measuring a second capacitance of the sensor at the end of the predetermined time period;
• determining a difference between the first and second capacitances;
• determining the concentration of the analyte based on the difference;
• associating the discrete frequency with the difference to determine a frequency response;
• and
• using the frequency response to determine the composition of the analyte.