Table 3.

Detect limits of sensors based on conducting polymers and their composites to several gas analytes

Analyte	Sensing material	Detect limit	Sensor type	Reference
NH3	PAni/SWNT	50 ppb	Chemresistor	[210]
NO2	PPy/PET	<20 ppm	Chemresistor	[36]
	PTh/CuPc	4.3 ppm	Chemresistor	[53]
	PAni/In2O3	<0.5 ppm	SAW	[216]
HCl	PAni/FeAl	0.2 ppm	Chemresistor	[235]
H2S	PAni/heavy metal salts	<10 ppm	Chemresistor	[66]
CO	PAni/FeAl	10 ppm	Chemresistor	[47]
	PAni/In2O3	<60 ppm	SAW	[216]
Water	PAni	< 25 ppm	Chemresistor	[30]
Methanol	PAni/Pd	<1 ppm	Chemresistor	[33]
Methane halide	Poly(3-methylthiophene)/MWNT	Several ppm	Chemresistor	[127]
	PAni/Cu	<10 ppm	Chemresistor	[101]
Acetone	PTh copolymer	200∼ 300 ppm	Chemresistor	[182]
Toluene	PTh copolymer	20 ppm	Chemresistor	[182]
Butylamine	Poly(anilineboronic acid)	10 ppb	Chemresistor	[80]