Sensor device and method for qualitative and quantitative analysis of gas phase substances

A sensor for detecting gas phase substances, comprising:

• a) a sensing element, comprising
• a first resistance temperature detector which functions as a temperature detector and a variable resistance heater, and
• a catalyst in thermal contact with the first resistance temperature detector;
• b) a reference element, comprising
• a second resistance temperature detector which functions as a temperature detector and a variable resistance heater;
• and
• c) a heat flow monitor for measuring the endothermic and exothermic heat flow to and from the sensing element relative to the reference element, resulting from thermal processes occurring at these elements.

A sensor for detecting gas phase substances, comprising:

• a) a sensing element, comprising
• first resistance temperature detector which functions as a temperature detector and a variable resistance heater, and
• a metal oxide catalyst in thermal contact with the first resistance temperature detector;
• b) a reference element, comprising
• a second resistance temperature detector which functions as a temperature detector and a variable resistance heater;
• c) a heat flow monitor for measuring the endothermic and exothermic heat flow to and from the sensing element relative to the reference element resulting from thermal processes occurring at these elements, comprising an Anderson Loop measurement circuit topology for observing the difference in the electrical resistance between the first resistance temperature detector and the second resistance temperature detector;
• and
• d) a feedback control system to regulate the heat flow to and from the sensing element, to maintain the sensing element at the desired instantaneous temperature.

A sensor for detecting gas phase substances, comprising:

• a) a sensing element, comprising
• a heater,
• a temperature detector in thermal contact with the heater, and
• a catalyst in thermal contact with the temperature detector and the heater;
• b) a heat flow monitor for measuring the endothermic and exothermic heat flow to and from the sensing element relative to the environment, resulting from thermal processes occurring at the sensing element.

A sensor for detecting gas phase substances, comprising:

• a) a sensing element, comprising
• a resistance temperature detector which functions as a temperature detector and a variable resistance heater, and
• a catalyst in thermal contact with the resistance temperature detector;
• and
• b) a heat flow monitor for measuring the endothermic and exothermic heat flow to and from the sensing element relative to the environment, resulting from thermal processes occurring at the sensing element.

A sensor for detecting gas phase substances, comprising:

• a) a first sensing element, comprising
• a first variable resistance heater,
• a first temperature detector in thermal contact with the first variable resistance heater, and
• a first catalyst in thermal contact with the first temperature detector and the first variable resistance heater;
• b) a second sensing element, comprising
• a second variable resistance heater,
• a second temperature detector in thermal contact with the second variable resistance heater, and
• a second catalyst in thermal contact with the second temperature detector and the second variable resistance heater;
• and
• c) a heat flow monitor for measuring the endothermic and exothermic heat flow to and from the first sensing element relative to the second sensing element, resulting from thermal processes occurring at these elements.

A method of detecting a gas phase substance at a predetermined temperature, comprising:

• a) contacting the substance with a sensing element and a reference element, wherein the sensing element comprises
• a first heater,
• a first temperature detector in thermal contact with the first heater, and
• a catalyst in thermal contact with the first temperature detector and the first heater;
• and wherein the reference element comprises
• a second heater,
• a second temperature detector in thermal contact with the second heater, and
• b) regulating the temperature of the sensing element and the reference element to substantially match the specific temperature at which reaction occurs between the catalyst and the substance;
• and
• c) measuring the heat flow to and from the sensing element relative to the reference element, resulting from exothermic and endothermic processes occurring at these elements.

A method of detecting a gas phase substance at a predetermined temperature, comprising:

• a) contacting the substance with a sensing element and a reference element, wherein the sensing element comprises
• a first resistance temperature detector which functions as a temperature detector and a variable resistance heater, and
• a catalyst in thermal contact with the first resistance temperature detector;
• and wherein the reference element comprises
• a second resistance temperature detector which functions as a temperature detector and a variable resistance heater;
• b) regulating the temperature of the sensing element and the reference element to substantially match the specific temperature at which reaction occurs between the catalyst and the substance;
• and
• c) measuring the heat flow to and from the sensing element relative to the reference element, resulting from exothermic and endothermic processes occurring at these elements.

A method of detecting a gas phase substance at a predetermined temperature, comprising:

• a) contacting the substance with a sensing element, wherein the sensing element comprises
• a first variable resistance heater,
• a first temperature detector in thermal contact with the first variable resistance heater, and
• a catalyst in thermal contact with the first temperature detector and the first variable resistance heater;
• b) regulating the temperature of the sensing element to substantially match the specific temperature at which reaction occurs between the catalyst and the substance;
• c) measuring the heat flow to and from the sensing element resulting from exothermic and endothermic processes occurring at the sensing element;
• d) contacting the substance with a reference element, wherein the reference element comprises
• a second variable resistance heater, and
• a second temperature detector in thermal contact with second the variable resistance heater;
• e) regulating the temperature of the reference element to substantially match the temperature of the sensor element;
• f) measuring the heat flow to and from the reference element resulting from exothermic and endothermic processes occurring at the reference element;
• g) comparing the heat flow to and from the sensing element with the heat flow heat flow to and from the reference element to detect the substance.

A method of detecting multiple gas phase substances by calorimetric spectroscopy, comprising:

• a) contacting the substance with at least one sensing element and at least one reference element, wherein the sensing element comprises
• a first variable resistance heater,
• a first temperature detector in thermal contact with the first variable resistance beater, and
• a catalyst in thermal contact with the first temperature detector and the first variable resistance heater;
• and wherein the reference element comprises
• a second variable resistance heater,
• a second temperature detector in thermal contact with the second variable resistance heater;
• b) increasing or decreasing the temperature of the sensing element and the reference element concurrently over a temperature range, such that the discrete temperature at which reaction occurs between the catalyst and a substance is momentarily achieved;
• c) measuring the heat flow to or from the sensing element relative to the reference element, resulting from exothermic and endothermic processes occurring at these elements, over the same temperature range.