Solvent and Phthalate Impurities of Health Concern in Tobacco-Derived and Synthetic Nicotine.

Solvents and phthalates in synthetic nicotine (SN) and tobacco-derived nicotine (TDN) were determined using gas chromatography-tandem mass spectrometry (GC-MS/MS) and GC-MS. The analysis revealed that 16 solvents were detected in SN at a total concentration of 2094 mg/kg, while 14 solvents were detected in TDN at a total concentration of 1538 mg/kg. The total solvent concentration found in SN was 1.4 times higher than that in TDN and that of the SN e-liquids was 1.8 times higher than that of the TDN e-liquids. Phthalate analysis showed that the total phthalate concentration in SN was approximately 11 times higher than that in TDN and that of SN e-liquids was approximately 15 times higher than that of TDN e-liquids. This appears to reflect that SN is more susceptible to solvent and phthalate contamination. Statistical analysis results showed that benzene, dichloromethane, toluene, and o-xylene showed statistically significant correlations between nicotine and their corresponding products. Overall, these results indicate that nicotine, especially SN, contains high levels of organic solvent and phthalate residues and should not be advertised as safe and pure.