Table 2S.

Preparation of liquid phase VOC standard for the analysis by the TD-GC-MS system.

A. Preparation of liquid phase standard for 19 VOCs
Compounds		Methanol	AA	PA	BA	IA	VA	B	T	S	p-X	m-X	o-X	MEK	MIBK	i-BuAl	BuAc	PPA	BTA	IVA	VLA
Primary grade chemical	Concentration (%)		99.0	97.0	99.0	97.0	97.0	99.5	99.5	99.0	99.0	99.0	97.0	99.0	99.5	99.0	99.5	99.0	99.0	99.0	99.0
PSa	Volume (μL)	13,700	900	300	300	300	300	300	300	300	300	300	300	300	300	300	300	300	300	300	300
	Concentration (ng·μL−1)		34,972	11,611	11,954	11,596	11,786	13,104	12,925	13,454	12,845	12,845	12,804	11,954	11,970	11,895	13,149	14,702	14,226	13,736	13,929
1st L-WSb	volume (μL)	19,800									200 (of PS)
	Concentration ( ng·μL−1)		350	116	120	116	118	131	129	135	128	128	128	120	120	119	131	147	142	137	139

B. Preparation of final working standard (F-WS) for 5 point calibration: absolute mass (ng) of VOC loaded on tube sampler
Order	Mixing volume (μL)		Concentration c (ng μL−1)
	1st L-WS	Methanol	AA	PA	BA	IA	VA	B	T	S	p-X	m-X	o-X	MEK	MIBK	i-BuAl	BuAc	PPA	BTA	IVA	VLA
1	14	1,486	3.26	1.08	1.12	1.08	1.10	1.22	1.21	1.26	1.20	1.20	1.20	1.12	1.12	1.11	1.23	1.37	1.33	1.28	1.30
2	70	1,430	16.3	5.42	5.58	5.41	5.50	6.12	6.03	6.28	5.99	5.99	5.98	5.58	5.59	5.55	6.14	6.86	6.64	6.41	6.50
3	140	1,360	32.6	10.8	11.2	10.8	11.0	12.2	12.1	12.6	12.0	12.0	12.0	11.2	11.2	11.1	12.3	13.7	13.3	12.8	13.0
4	280	1,220	65.3	21.7	22.3	21.6	22.0	24.5	24.1	25.1	24.0	24.0	23.9	22.3	22.3	22.2	24.5	27.4	26.6	25.6	26.0
5	700	800	163	54.2	55.8	54.1	55.0	61.2	60.3	62.8	59.9	59.9	59.8	55.8	55.9	55.5	61.4	68.6	66.4	64.1	65.0

^aPS: Dilution of pure chemical (primary grade chemical) to make 20 mL solution

^b1st L-WS: Dilution of PS to make 20 mL solution

^cAnalysis volume: 1 μL