Table 2.

Concentrations of mercapturic acid metabolites of VOCs measured in 24-hour urine during e-cigarette use.

Exposure (biomarker)Cig-a–like (mean, SD)Fixed-power (mean, SD)Variable-power (mean, SD)Pod (mean, SD)Difference (P)
(ng/mg creatinine)(n = 12)(n = 15)(n = 6)(n = 3)All includedPods excluded
Acrolein (3-HPMA)260.6 (236.0)238.7 (189.8)340.7 (173.1)188.0 (49.9)0.0810.100
Acrylamide (AAMA)117.4 (65.9)103.2 (43.6)118.8 (35.1)131.9 (58.9)0.3250.311
Acrylonitrile (CNEMA)27.5 (28.6)20.8 (15.6)17.1 (3.79)13.1 (13.4)0.4420.950
1,3-Butadiene (MHBMA-1+2)0.51 (0.36)0.57 (0.50)0.50 (0.43)0.19 (0.07)0.0550.730
1,3-Butadiene (MHBMA-3)0.16 (0.09)0.15 (0.09)0.24 (0.23)0.08 (0.05)0.0190.363
Benzene (PMA)0.54 (0.22)0.48 (0.41)0.38 (0.20)0.39 (0.19)0.0810.129
Crotonaldehyde (HPMMA)152.4 (68.0)194.2 (128.6)132.5 (30.5)171.3 (71.6)0.4770.242
Ethylene oxide (HEMA)1.56 (0.64)1.35 (1.25)1.73 (1.31)1.27 (1.40)0.0900.124
Methylating agent (MMA)15.7 (9.3)18.8 (27.0)18.7 (23.7)13.6 (12.8)0.6010.865
Propylene oxide (2-HPMA)34.2 (17.4)62.6 (55.0)75.8 (26.4)42.2 (19.6)<0.0010.001