Respiratory Sampling System for Diabetes Detection

In recent years, the electronic nose system developed in the laboratory has been widely used in the agricultural field (17 (link), 18 (link)). Based on these studies, the respiratory sample collection system in this paper was developed for diabetes detection, as shown in Fig. 1.
Figure 1

Physical view of electronic nose system.

The system consists of 32 commercial gas sensors and their target gases are shown in Table 1. The main component sensor of the electronic nose uses a metal oxide semiconductor sensor. Due to the diversity of respiratory gas composition in diabetic patients, such as ethanol (19 (link)), carbon monoxide (20 (link)), alkanes (21 (link)), and methyl nitrate (22 (link)), sensors of different measurement ranges and different companies are used. These different sensors can form a complementary array that can help identify the disease being studied. By calculating the cost of purchasing the corresponding equipment, we can see that the total cost is about $674. The volume is about 7728 cubic centimeters. Before using the detection device, put the electronic nose device into the fume hood first and allow the sensor to warm up for 30 min. Then, the gas to be measured was fed into the bionic chamber attached with a sensor through an air pump with a flow rate of 1.2 L/min. When the gas entered the chamber, the data were sampled immediately, and the collection time was 1 min. When one set of gas collection is completed, the air pump draws fresh air to clean the residual gas in the chamber for 3–5 min to restore the sensor to the baseline level before the next set of sampling.
Table 1

Summary of the sensor array.

Number	The gas sensor	The response characteristics
S1	TGS2612	Butane, methane, propane.
S2	TGS2611	Methane, natural gas
S3	TGS2620	Vapors of organic solvents, ethanol
S4	TGS2603	Gaseous air contaminants, trimethylamine, methyl thiol, etc.
S5	TGS2602	Gaseous air contaminants, VOCs, ammonia, hydrogen sulfide, etc.
S6	TGS2610	Propane, butane
S7	TGS2600	Gaseous air contaminants, hydrogen, alcohol, etc
S8	GSBT11	Formaldehyde, oluene, butyric acid, butane, hydrocarbons
S9	MS1100	Formaldehyde, toluene, xylene
S10	MP135	Hydrogen, alcohol, carbonic oxide
S11	MP901	Alcohol, smoke, formaldehyde, toluene, acetone, benzene
S12	MP-9	Carbonic oxide, methane
S13	MP-3B	Alcohol
S14	MP-4	Methane, natural gas, biogas
S15	MP-5	Liquefied petroleum gas
S16	MP-2	Propane, smoke
S17	MP503	Alcohol, smoke
S18	MP801	Benzene, toluene, formaldehyde, alcohol, smoke
S19	MP905	Benzene, toluene, formaldehyde, alcohol, smoke
S20	MP402	Methane, natural gas, biogas
S21	WSP1110	Nitrogen dioxide
S22	WSP2110	Toluene, benzene, formaldehyde, alcohol, etc.
S23	WSP7110	Sulfuretted hydrogen
S24	MP-7	Carbonic oxide
S25	TGS2612	Butane, methane, propane
S26	TGS2611	Methane, natural gas
S27	TGS2620	Vapors of organic solvents, combustible gases, methane, carbon monoxide, isobutane, hydrogen, ethanol
S28	MP-3B	Alcohol
S29	MP702	Ammonia gas
S30	TGS2610	Propane, butane
S31	TGS2600	Gaseous air contaminants, methane, carbon monoxide, isobutane, ethanol, hydrogen
S32	TGS2618-COO	Butane, LP gas

Manufacturers: S1–S7, S25–S27, S30–S32 Figaro Engineering Inc, Minoh, Japan; S8 Orgam Technologies, Gwangju, Korea; S9–S24, S28–S29, Winsen Electronics Technology, Zhengzhou, China.