Table 2.

QEPAS detection of trace gases using different QEPAS approaches. IT – signal integration time.

Molecule (Target analyte)	Frequency cm−1	Pressure Torr	NNEA cm−1W/Hz−1/2	Power mW	NEC ppm		QEPAS system		IT (s)	Ref.
NH3 (exhaled air) Ammonia	6,528.76	90	8·10−9	7	5		On-beam		1	[26]
CO2 (exhaled air) Carbon dioxide	6,514.25	90	10·10−9	5.2	890		On-beam		1	[26]
H2O (exhaled air) Water	6,541.29	90	8·10−9	5.2	580		On-beam		1	[26]
NH3 (N2) Ammonia	6,528.76	60	7.2·10−9	38	0.65		On-beam		1	[27]
H2CO (air) Formaldehyde	2,832.48	200	2.2·10−8	3.4	0.55		On-beam		1	[28]
N2O (air+5%SF6) Nitrous oxide	2,195.63	50	1.5·10−8	19	0.007		On-beam		1	[29]
CO (N2) Carbon monoxide	2,196.66	50	5.3·10−7	13	0.5		On-beam		1	[29]
CO (in propylene) Carbon monoxide	2,196.66	50	7.4·10−8	6.5	0.14		On-beam		1	[30]
CO2 (air+1. 2%H2O) Carbon dioxide	4,991.26	50	1.4·10−8	4.4	18		On-beam		1	[31]
HCN (air+50% RH) Hydrogen cyanide	6,539.11	60	4.6·10−9	50	0.155		On-beam		1	[32]
CO2 (N2+1.5%H2O) Carbon dioxide	4,991.26	50	1.4·10−8	4.4	18		On-beam		1	[33]
NH3 (N2) Ammonia	4,986.99	50	8.9·10−9	3.9	3		On-beam		1	[33]
H2O (N2) Water	7,306.75	60	1.9·10−9	9.5	0.09		On-beam		1	[34]
C2H2 (N2) Acetylene	6,529.17	75	2.5·10−9	40	0.06		On-beam		1	[34]
CH4 (N2) Methane	6,057.09	950	2.9·10−8	14	2.1		On-beam		1	[35]
H2CO (N2:75% RH) Formaldehyde	2,804.90	75	8.7·10−9	7.2	0.12		On-beam		1	[34]
C2H5OH (N2) Ethanol	1,934.2	770	2.2·10−7	10	90		On-beam		1	[34]
C2HF5 (Freon125) Pentafluoroethane	1,208.62	770	7.9·10−9	6.6	0.009		On-beam		1	[25]
C2H4 (N2) Ethylene	6,177.07	770	5.4·10−9	15	1.7		On-beam		0.7	[94]
H2O (N2) Water	7,165.82	770	1.68·10−8	8	9.27		On-beam		1	[36]
NO (N2 humidified) Nitric oxide	1,900.08	250	7.5·10−9	100	0.005		On-beam		1	[60]
NH3 (N2) Ammonia	6,528.76	575	3.3·10−9	25	0.06		On-beam		10	[38]
H2S (N2) Hydrogen sulfide	6,357.63	780	5.6·10−9	45	5		On-beam		1	[39]
CO2 (N2) Carbon dioxide	6,321.20	770	4.0·10−9	38	123		On-beam		1	[39]
CH4 (N2+1.2%H2O) Methane	6,057.09	770	3.7·10−9	16	0.24		On-beam		1	[39]
C2H2 (N2) Acetylene	6,529.17	770	3.3·10−9	37	0.085		On-beam		1	[40]
NH3 (air humidified) Ammonia	967.35	130	/	24	0.006		On-beam		1	[41]
CO2 (air humidified) Carbon dioxide	6,361.25	150	8.2·10−9	45	40		On-beam		1	[41]
NH3 (N2+2.3%H2O) Ammonia	6,528.76	50	9.1·10−9	50	1.27		On-beam		1	[43]
CH4 (N2+2.3%H2O) Methane	6,057.1	200	2.45·10−8	16	3.2		On-beam		1	[43]
CO (N2+2.2%H2O) Carbon monoxide	2,176.28	100	1.48·10−8	71		0.002	On-beam		1	[44]
CO (N2+2.6%H2O) Carbon monoxide	2,169.2	760	1.61·10−8	400		0.0015	On-beam		1	[45]
N2O (N2+2.6%H2O) Nitrous oxide	2,169.6	100	2.91·10−9	400		0.023	On-beam		1	[45]
CH4 (N2) Methane	4,245.84	770	/	1.2		1	On-beam		0.1	[46]
CH4 (N2) Methane	2,958.23	770	4.06·10−9	1		0.1	On-beam		12	[47]
C2H2 (N2) Acetylene	6,523.88	720	4.1·10−9	57		0.03	On-beam		1	[48]
HCl (N2) Hydrochloric acid	5,739.26	760	5.2· 10−8	15		0.7	On-beam		1	[49]
SO2 (N2+2.4%H2O) Sulfur dioxide	1,380.94	100	2.0·10−8	40		0.1		On-beam	1	[50]
C2H6 (N2) Ethane	2,990.08	150	7.0·10−7	217		0.025		On-beam	3	[95]
O2 (N2) Oxygen	13,099.3	158	4.74·10−7	1228		13		On-beam	1	[96]
H2O (air) Water	7,161.41	760	6.2·10−9	8		0.26		off-beam	1	[55]
O3 (air) Ozone	35,087.7	700	3.0·10−8	0.8		1.27		off-beam	1	[58]
SF6 Sulfur hexafluoride	948.62	75	2.7·10−10	18		5·10−5		fiber-coupled	1	[66]
N2H4 (N2) Hydrazine	6,570.00	700	/	62		1		MOCAM	1	[67]
C2H2 (air) Acetylene	6,523.88	760	1.96·10−6	9.8		1.58·104		evanescent wave PAS	1	[75]
CH3OH (N2) Methanol	131.05	10	2·10−10	0.04		7		bare custom QTF	4	[88]