Breath analyser and detection methods
A measurement device for measuring a concentration of a component of a gas mixture includes a chamber that contains the gas mixture, a light source that emits light into the chamber, the emitted light having a wavelength between 230 nm and 320 nm, and a light sensor that detects a portion of the light from the light source that has propagated through the gas mixture. A processor is configured to determine the concentration of the component of the gas mixture based on the portion of the light emitted from the light source that is detected by the light sensor. The light source may include one or more LEDs, each having a central wavelength of light emission between 270 nm and 320 nm and a linewidth of less than 50 nm. The device may be employed to determine acetone concentration in exhaled breath, which may be indicative of diabetes or other health conditions.
1. A measurement device for measuring a concentration of a component of a gas mixture comprising:
a chamber for receiving the gas mixture;
at least one light source that emits light into the chamber, the emitted light including a wavelength between 230 nm and 320 nm;
at least one light sensor that detects a portion of the light from the light source that has propagated through the gas mixture in the chamber; and
a processor configured to determine the concentration of the component of the gas mixture based on the portion of the light emitted from the light source that is detected by the light sensor;
wherein the at least one light source comprises a first light source including a LED with a central wavelength of light emission between 240 nm and 270 nm, and a second light source including a LED with a central wavelength of light emission between 270 nm and 300 nm, and
wherein the LEDs of the first and second light sources each has a linewidth of light emission of less than 50 nm.
2. The measurement device of claim 1 , wherein the at least one light source includes an LED of an Al y In x Ga 1-x-y N material where 0≦x≦1 and 0≦y≦1.
3. The measurement device of claim 1 , wherein the chamber has a first window for transmitting light from the light source into the chamber, and a second window for transmitting light from the chamber to the light sensor, wherein the first window and the second window comprise a disposable window module that is removable for replacement.
4. The measurement device of claim 1 , wherein the chamber has a first cavity mirror for transmitting light from the light source into the chamber, and a second cavity mirror for transmitting light from the chamber to the light sensor, wherein the first and second cavity mirrors form an optical cavity to increase a path length of the light emitted from the light source.
5. The measurement device of claim 1 , wherein the at least one light sensor further comprises a photodetector for detecting light due to fluorescence from the component of the gas mixture absorbing the light emitted from the light source.
6. The measurement device of claim 1 , wherein the chamber includes a mirror structure that reflects light within the chamber to increase a path length of the light emitted from the light source.
7. The measurement device of claim 1 , wherein the chamber includes a heating element for heating a surface of the chamber.
8. The measurement device of claim 1 , wherein the chamber includes an inlet valve for introducing gas into the chamber, and an outlet valve for venting gas from the chamber, wherein the inlet and outlet valves are light tight valves.
9. The measurement device of claim 1 , wherein the processor is configured to determine a total concentration of one or more ketones in the gas mixture.
10. The measurement device of claim 9 , wherein the gas mixture is exhaled breath, and the processor is configured to determine a total concentration of the one or more ketones in the exhaled breath.
11. The measurement device of claim 9 , wherein the one or more ketones comprises acetone.