Preparation of needle trap samplers to extract air compounds from indoor electric-vaporizing sources

Figures & data

Figure 1. Schematic SPME and needle trap samplers.

Table 1. Main air compounds of heating electric-vaporization anti-mosquito mats

Chemical	Concentration (ppbv)^a
Acetone	80 (0.2)
Benzene	5.2 (0.1)
Butane	2.6 (0.4)
1-Butene	2.6 (0.3)
Chloroform	1.6 (0.0)
Cyclohexane	1.8 (0.8)
Dichloromethane	211 (7.6)
n-Decane	754 (10.3)
Dodecane	135 (15.2)
Ethylbenzene	3.0 (0.1)
m-Ethyltoluene	2.7 (0.0)
o-Ethyltoluene	2.2 (0.0)
p-Ethyltoluene	1.5 (0.1)
Heptane	1.8 (0.1)
Hexane	21.8 (0.1)
Isopentane	5.9 (0.2)
Methylcyclohexane	1.1 (0.0)
2-Methylheptane	3.9 (0.1)
3-Methylheptane	3.4 (0.3)
n-Nonane	51.9 (2.2)
n-Octane	11.9 (1.2)
n-Propylbenzene	1.2 (0.1)
Toluene	15.8 (0.4)
1,2,3-Trimethylbenzene	1.1 (0.0)
1,2,4-Trimethylbenzene	4.0 (0.1)
1,3,5-Trimethylbenzene	1.7 (0.2)
m/p-Xylene	8.4 (0.1)
o-Xylene	6.2 (0.1)
n-Undecane	624 (9.1)

Note: ^aThe concentrations are displayed in mean values and standard deviations (in parentheses) of triple duplicates.

Table 2. Sampling flow rates for needle trap samplers in this study

Sampler	Number of Samplers	Sampling Flow Rate (Mean Value, mL/min)
Hollow needle	14	762 (RSD = 3.0%)
NTS Group 1 (60–80 mesh)	4	81.6 (RSD = 4.0%)
NTS Group 2 (80–100)	4	70.0 (RSD = 4.1%)
NTS Group 3 (100–120 mesh)	6	49.8 (RSD = 2.7%)

Figure 2. Extractions of BTEX by TWA sampling using NTS (60–80, 80–100, and 100–120 mesh DVB).

Table 3. BTEX extracting mass and rates for needle trap samplers

Adsorbent of NTS	Sampling Time (min)	VOC	Extracting Rate (ng/min)
60–80 mesh DVB	60	Benzene	2.67
		Toluene	3.42
		Ethylbenzene	3.83
		o-Xylene	4.60
	120	Benzene	2.73
		Toluene	3.33
		Ethylbenzene	3.90
		o-Xylene	4.97
80–100 mesh DVB	60	Benzene	3.82
		Toluene	5.65
		Ethylbenzene	6.12
		o-Xylene	6.88
	120	Benzene	3.70
		Toluene	5.68
		Ethylbenzene	5.90
		o-Xylene	7.00
100–120 mesh DVB	60	Benzene	5.12
		Toluene	6.48
		Ethylbenzene	8.41
		o-Xylene	8.30
	120	Benzene	5.32
		Toluene	6.91
		Ethylbenzene	8.40
		o-Xylene	8.76

Table 4. Gas chromatographic analysis for main products from electric-vaporization anti-mosquito mats via needle trap and SPME samplers

Sampler	Retention Time (min)^a	Integrated Area by GC-FID
NTS	4.58	1.3
60–80 mesh DVB	5.637	4
	6.689	7.3
	7.704	4.5
	9.653	2.5
NTS	4.568	2.5
80–100 mesh DVB	5.629	11.5
	6.683	23.7
	7.7	14.3
	9.651	8.6
NTS	4.564	4.2
100–120 mesh DVB	5.626	13.3
	6.681	25.3
	7.696	17.1
	9.646	4.5
SPME	4.556	2.7
	5.62	6.6
	6.677	9
	7.694	4.4
	9.644	2.1

Note: ^aThe sequence of retention times respectively indicates five compounds: acetone, dichloromethane, n-decane, n-undecane, and dodecane.

Figure 3. Chromatograph diagrams of NTS and SPME for extracting products from electric-vaporization anti-mosquito mats.