Chemical detection using calorimetric spectroscopy

A chemical detector, comprising:

• an array of sensing elements micro cantilever sensing elements, each of said sensing elements having a characteristic physical parameter and each of said sensing elements having a coating exhibiting a preferential adsorption of at least one chemical to be sensed;
• means for exposing said coatings to an unknown sample of at least one chemical to be analyzed, said coatings adsorbing said at least one chemical to be sensed if present in said sample;
• a source of a monochromatic spectrum for respectively radiating said array of sensing elements with different wavelengths of said monochromatic spectrum;
• and,
• means for recording signals representative of said physical parameter of each of said sensing elements in said array responsive to said radiation of said different wavelengths, measurable changes of said physical parameter due to said adsorbing defining a unique photothermal signature of a detected chemical.

A chemical detector, comprising:

• an array of sensing elements, each of said sensing elements having a characteristic physical parameter and each of said sensing elements having a coating exhibiting a preferential adsorption of at least one chemical to be sensed;
• means for exposing said coatings to an unknown sample of at least one chemical to be analyzed, said coatings adsorbing said at least one chemical to be sensed if present in said sample;
• a source of a monochromatic spectrum for respectively radiating said array of sensing elements with different wavelengths of said monochromatic spectrum;
• a housing having an infrared transmissive panel, with a minimized adsorption characteristic, defining a first chamber in which said array is disposed and into which said sample can be admitted and a second chamber in which said monochromator is disposed, said monochromator being thereby isolated from said sample;
• and,
• means for recording signals representative of said physical parameter of each of said sensing elements in said array responsive to said radiation of said different wavelengths, measurable changes of said physical parameter due to said adsorbing defining a unique photothermal signature of a detected chemical.

A method for sensing chemicals, comprising the steps of:

• preferentially adsorbing at least one chemical to be sensed onto an array of sensing elements having a measurable characteristic physical parameter;
• measurably changing said characteristic physical parameter of said sensing elements by exposing said coatings to an unknown sample of at least one chemical to be analyzed, said coatings adsorbing said at least one chemical to be sensed if present in said sample;
• respectively heating said sensing elements by radiating said sensing elements with different wavelengths of a monochromatic spectrum;
• measuring said changing of said physical parameter of said sensing elements due to said adsorbing;
• and,
• defining a unique photothermal signature of a detected chemical with said measurable changes of said physical parameter.

A spectrometer, comprising:

• a plurality of sensing elements in an array, each of said sensing elements having a coating exhibiting a preferential adsorption of at least one chemical to be sensed and each of said sensing elements having a measurable physical characteristic;
• means for exposing said coatings to an unknown sample of at least one chemical to be adsorbed by said coatings as an analyte if present in said sample, said physical parameter of said sensing elements being changed by said adsorbing;
• a source of a monochromatic spectrum for preferentially illuminating and heating said thermal detectors according to quantities of said adsorbed analyte;
• and,
• means for recording signals representative of said measurable changes of said physical parameter of each of said sensing elements in said array responsive to said heating by said monochromatic illumination, said recorded signals exhibiting improved signal-to-noise ratios.