Table 1.

Summary of the literature review of the selected metal-oxide based sensors for acetone detection with special emphasis to exhaled acetone measurements in term of diabetes monitoring.

Material	Max. Response	Temp. (°C)	Acetone (ppm)	LOD 1 (ppm)	Reference
NiO/SnO2	20.18 Ra/Rg 2	300	50	0.01	[42]
NiFe2O4	30.4 Rg/Ra	160	200	0.52	[52]
SnO2/SiO2	2193.7 Ra/Rg − 1	270	300	0.5	[46]
TiO2/In2O3	33.34 Rg/Ra	250	10	0.1	[53]
Sb/In2O3	64.3 Ra/Rg	240	50	-	[54]
C3N4-SnO2	11 Vg/Va 3	380	20	0.087	[43]
GO-SnO2-TiO2	60 Ra/Rg	200	5	0.25	[46]
ZnO:Pt	188.0 Ra/Rg	400	1000	1	[55]
ZnO:Nb	224.0 Ra/Rg	400	1000	1	[55]
Pd/LaFeO3	1.19 Rg/Ra	200	1	1	[57]
Pt0.3Au0.7–In2O3	40 Rg/Ra	160	50	0.3	[58]
CuFe2O4/α-Fe2O3	14 Ra/Rg	275	70	0.1	[59]
ZnO–Fe3O4	47 Ra/Rg	475	50	0.15	[60]
ZnCo2O4	38 Rg/Ra	200	500	0.5	[61]
Co3O4	17 Rg/Ra	111	1000	-	[62]
Co1−xZnx Fe2O4	−112 mV	650	50	0.3	[63]
TiO2	25.97 Ra/Rg	370	500	-	[64]
Ru/WO3	7.3 Ra/Rg	300	1.5	0.5	[47]
WO3 NFs	90 Ra/Rg	350	5	0.4	[48]
WO3/Pt-GNs	12 Ra/Rg	200	10	1	[49]
In/WO3-SnO2	66.5 Ra/Rg	200	50	1	[45]

¹ LOD—Limit of Detection. ² R_a/R_g—electrical resistance under exposure to air and target gas (acetone), respectively. ³ V_a/V_g—electrical voltage under exposure to air and target gas (acetone), respectively.