Composition of aerosols from thermal degradation of flavors used in ENDS and tobacco products

Figures & data

Figure 1. Structures of the parent compounds, cinnamaldehyde (A), eugenol (B), menthol (C), and vanillin (D).

Figure 2. Diagram of the drop-tube furnace within a quartz tube used to heat flavorants.

Table 1. Compounds (5) of highest concentration in each flavorant atmosphere (excluding the parent flavorant).

Low temperature (250 °C)		High temperature (750 °C)
Compound	Concentration (mg/m^3)	Compound	Concentration (mg/m^3)
Cinnamaldehyde
Eugenol	158	Benzene	189
Benzoic acid	27.4	Acetylene	135
2,4-Dimethylbenzoic acid	24.3	Ethene	98.0
Vanillin	10.7	2,4-Dimethylbenzoic acid	26.4
Nonanoic acid	4.62	Naphthalene	26.1
Eugenol
Vanillin	75.8	Ethene	42.2
Benzoic acid	18.2	Vanillin	38.8
Naphthalene	11.3	Acetylene	32.6
2,4-Dimethylbenzoic acid	9.28	Benzene	32.1
Acenaphthylene	6.31	1-Butene	26.6
Menthol
Benzoic acid	19.7	Benzoic acid	19.9
2,4-Dimethylbenzoic acid	7.67	2,4-Simethylbenzoic acid	6.33
Hexanoic acid	3.69	Propene	4.06
Isophthalic acid	3.56	Ethene	4.03
Succinic acid	1.25	Isophthalic acid	3.30
Vanillin
Acetylene	26.7	Benzoic acid	14.0
Ethene	17.4	Benzene	10.2
Iso-butane	14.0	2,4-Dimethylbenzoic acid	5.18
Benzoic acid	12.5	Vanillic acid	4.77
Benzene	11.9	Isophthalic acid	2.64

Table 2. Identified compounds determined by mass spectral analysis of flavorant atmosphere samples at low and high temperatures.

	Eugenol low	Vanillin low	Menthol high	Cinn low	Menthol low	Cinn high	Eugenol high	Vanillin high
[1-(2,4-Cyclopentadien-1-ylidene)ethyl]-Benzene,	Low	Low	High
2,3-Ddihydroxy benzoic acid
2,5-Dihydroxy benzeneacetic acid								High
2,5-Dihydroxyacetophenone	Super high
3-Methoxy benzenepropanoic acid	High	Low	Low				Very low	Very low
9-Methylene-9H-Fluorene		High
Benzeneacetic acid, 3-methoxy, methyl ester	Medium
α-Methylstyrene						Med	Med
β-Citronellol	Low						Med	High
[2-(Acridin-9-ylamino)-phenyl]-phenyl-methanone		Med	Low
1-Butanol, 3-methyl-, acetate	Med
1-Hydroxy-3-methoxy-6-methylanthraquinone	Low
1-Hydroxy-4-methoxy-3-(2-methoxy-6-oxo-1-cyclohexenyl)-, acetate	Low
1-Methoxy-2,3-dihydroxybenzene	very High							Medium
1-Phenylpropene						Low
2-Methoxyphenylacetone				High		Low
2-Methyl-1,1′-Biphenyl	Low	Low	High
2-Propenal, 3-phenyl-	High
2,5-Dimethylphenol	Very low						Med	Very low
3-Hydroxy benzoic acid	Med							Low
3-Hydroxy-4-methoxy cinnamic acid	High
3,4-Dihydroxy Benzoic acid	High	Med	High
3,4-Dimethylbenzoic acid				Medium		Med
4-Hydroxy cinnamic acid	High	Low				High	Med
Acetic acid, cinnamyl ester				High		High
Acetophenone	Very low	Low	Low	High	Low	High	High	Low
Benzene, (1-methylethyl)-							Low
Benzene, 1-propynyl-	Very low	High	High	Med	Low	High	High	High
Benzene, 1,3-diethenyl-	Very low	Low		High	Very low	High	Med	Very low
Benzene, 2-propenyl-						High	High
Benzeneacetic acid hydroxy methyl ester	Medium	Super high				Very low	Very low	High
Benzenepropanoic acid, 4-hydroxy							High
Benzofuran		Med	Low	Low		Med	Med	Very Low
Benzoic acid methyl ester	High	Very low
Benzoic acid, 2-methoxy-, methyl ester				High			Med
Cinnamaldehyde		High		Super high*	Medium	Super high*	Medium
Cinnamaldehyde, β-methyl-	High						High
Coniferyl aldehyde	High						Very low
Cyclohexene, 3-methyl-6-(1-methylethyl)-			Med
Cyclohexene, 4-methyl-1-(1-methylethyl)-			High
Ethanone, 1,1′-(1,3-phenylene)bis-		Med	Med	Med	Low	Med		Low
Hydroxy benzoic acid	Low		Medium	Low	Medium	Low
Menthol	Super high	Super high	Super high	Super high	Super high		Super high	Super high
Menthyl acetate			High		High
Methyl ester of 3,4,5-Trimethoxycinnamic acid	High
Methylphenol							High
o-Methylphenol						Medium	High
Phenol, 4-(2-propenyl)-				High			Low
Phenol, 4-(2-propenyl)-	High
Phenylethyne		Med	Med			Med	Med
Propionic acid, 3-benzoyl				Low

*Parent Compound

Figure 3. Volatile organic aromatic hydrocarbons measured in the flavorant aerosols at low (blue; 250 °C) and high (red; 750 °C) temperatures.

Figure 4. Polycyclic aromatic hydrocarbons (PAH) measured in the flavorant aerosols at low (blue; 250 °C) and high (red; 750 °C) temperatures.

Figure 5. Proportion of total measured organic compounds for each of the flavorants in the low (250 °C) and high (750 °C) temperature-generated atmospheres. Individual listed compounds were measured in the highest abundance (excluding parent flavorant).