Table 1.

Emitted carbonyls identified in vaping emissions of PG-VG and four flavored e-liquids. The signature ions (m/z) of carbonyl-PFBHA oxime derivatives were used to characterize carbonyl identities in Figure 1.

#	Emitted Carbonyls	CAS #	Formula	Signature Ions (m/z)	Retention Time A (min)	PG-VG	trans-2-Hexenol	Benzyl Alcohol	l-(-)-Menthol	Linalool
1	formaldehyde	50-00-0	CH2O	181, 195, 225	4.79	+	+	+	+	+
2	acetaldehyde	75-07-0	C2H4O	181, 209, 239	6.74, 6.87	+	+	+	+	+
3	acetone	67-64-1	C3H6O	181, 223, 236, 253	8.27	+	+	+	+	+
4	propionaldehyde	123-38-6	C3H6O	181, 236, 253	9.00, 9.24	+	+	bdl	bdl	+
5	acrolein	107-02-8	C3H4O	181, 231, 250, 251	9.13, 9.37	+	+	bdl	bdl	+
6	butyraldehyde	123-72-8	C4H8O	181, 239, 267	11.84, 12.02	bdl	+	bdl	bdl	bdl
7	trans-2-hexenal	6728-26-3	C6H10O	181, 293	16.46, 16.52	bdl	+	bdl	+	+
8	benzaldehyde	100-52-7	C7H6O	181, 301	18.25, 18.35	bdl	bdl	+	bdl	bdl
9	trans-2-methyl-2-butenal	497-03-0	C5H8O	181, 279	18.90	bdl	+	bdl	bdl	bdl
10	3-methyl-2-butenal	107-86-8	C5H8O	181, 279	19.97, 20.26	bdl	bdl	bdl	bdl	+
11	methyl glyoxal	78-98-8	C3H4O2	181, 462	20.67, 21.24, 21.29, 21.51	+	+	+	+	+
12	glyoxal	107-22-2	C2H2O2	181, 448	21.09, 21.16, 21.23	+	+	+	+	+
13	dimethylglyoxal	431-03-8	C4H6O2	181, 476	21.70	+	+	bdl	+	+
14	2-methyl-2-pentenal	623-36-9	C6H10O	181, 293	22.12	bdl	+	bdl	bdl	bdl

#: Number. ^A: Retention times of carbonyl-PFBHA oxime stereoisomers (E and Z) if applicable. +: Carbonyls detected (S/N > 3). bdl, below detection limit (S/N < 3).