Compositions and methods for gas sample analysis
A method of detecting acetone in a gas sample, comprising, at an operation temperature of 50° C. or less, exposing the gas sample to a gas sensor comprising an electrode and a sensing material deposited on the electrode, wherein the sensing material comprises tungsten bronze, and a level of the acetone in the gas sample is detected by a change in resistivity of the sensing material.
1. A gas sensor comprising: an electrode and a sensing material deposited on the electrode, wherein the sensing material comprises a tungsten bronze, a carbon complex of the tungsten bronze, or a complex of the tungsten bronze with reduced graphene oxide, and the gas sensor has a limit of detection of 100 parts per million (ppm) or less of acetone in a gas sample at an operation temperature of 50° C. or less, wherein the tungsten bronze is Na 0.12 K 0.2 WO 3 .
2. The gas sensor of claim 1 , wherein the limit of detection is 50 ppm or less.
3. The gas sensor of claim 1 , wherein the electrode has a substrate chosen from ceramic, silica, silicon, glass, a printed circuit board (PCB), or a polyethylene terephthalate (PET) substrate.
4. The gas sensor of claim 1 , further comprising a depositing solvent, an adhesive, or both.
5. The gas sensor of claim 1 , wherein the sensing material is in a shape of a film.
6. A wearable device comprising the gas sensor of claim 1 .
7. The wearable device of claim 6 , wherein the wearable device has a volume of 5 cm 3 or less.
8. The wearable device of claim 6 , wherein the wearable device has a power consumption of 5 μAmp or less.
9. The wearable device of claim 6 , wherein the wearable device comprises a shoe, an armband, a sleeve, a jacket, glasses, eye wears, goggles, a glove, a ring, a watch, a wristband, a bracelet, nose ring, ear bud, earphone, an article of clothing, a hat, a headband, a headset, a bra, or jewelry.
10. The wearable device of claim 6 , wherein the wearable device is configured to calibrate itself and/or to digitally read concentration of acetone.
11. The wearable device of claim 6 , wherein the wearable device is configured to connect with a computer or smartphone that displays metabolic profiles, fat burning status, diet and fitness efficiency, or a combination thereof, in a subject wearing the wearable device.