The impact of sucralose and neotame on the safety of metal precipitation in electronic cigarettes

Abstract

This study investigated the impact of sweeteners on the release of heavy metals during the heating and atomization processes in electronic cigarettes. Based on a PG/VG base e-liquid with the addition of 2% and 5% neotame or sucralose, we quantitatively analyzed the impact of sweetener content on the levels of heavy metals such as Ni, Cr, and Fe in the e-liquid and aerosol after heating and atomization. Additionally, the heated e-liquid samples were used to culture SH-SY-5Y and Beas-2B cells, and their cytotoxic effects were assessed using the CCK-8 assay. The results indicated that the e-liquid with 5% sucralose had the highest average levels of heavy metals after heating and atomization, particularly nickel (13.36 ± 2.50 mg/kg in the e-liquid and 12,109 ± 3,229 ng/200 puffs in the aerosol), whereas the e-liquid with neotame had significantly lower average heavy metal content in comparison. Additionally, it was measured that the chloride ion concentration in the e-liquid with 5% sucralose reached 191 mg/kg after heating at 200°C for 1 h, indicating that heating sucralose generated chloride ions, Which might corrode metal parts components leading to heavy metal release. Cytotoxicity tests revealed that the base e-liquid without sweeteners exhibited the highest average cell viability after heating, at 64.80% ± 2.84% in SH-SY-5Y cells and 63.24% ± 0.86% in Beas-2B cells. Conversely, the e-liquid variant with 5% sucralose showed a significant reduction in average cell viability, reducing it to 50.74% ± 0.88% in SH-SY-5Y cells and 53.03% ± 0.76% in Beas-2B cells, highlighting its more pronounced cytotoxic effects compared to other tested e-liquids. In conclusion, sucralose in e-liquids should be limited preferably less than 2%, or replaced with neotame, a safer alternative, to minimize health risks.

Keywords: aerosol; cytotoxicity; electronic cigarettes; heavy metals; neotame; sucralose.

FIGURE 1

Distribution of heavy metals in original e-liquids containing different sweeteners.

FIGURE 2

Distribution of heavy metals in e-liquid after heating through a nickel-chromium alloy mesh coil.

FIGURE 3

Types and concentrations of heavy metals in aerosols from e-liquids with different sweeteners.

FIGURE 4

The effect of e-liquids with different sweeteners and concentrations on the viability of SH-SY-5Y and Beas-2B cells after heating.

FIGURE 5

Surface morphology and material composition analysis of the mesh coil. (A) SEM surface morphology image of the mesh coil. (B) Energy spectrum analysis chart of the mesh coil material. (C) Elemental composition percentage of the mesh coil.

FIGURE 6

SEM images of the mesh coil surface after heating different e-liquids. (A) Surface of the original mesh coil without heating, (B) Heated with pure PG/VG e-liquid, (C) PG/VG/Neotame (2%), (D) PG/VG/Neotame (5%), (E) PG/VG/Sucralose (2%), (F) PG/VG/Sucralose (5%).

FIGURE 7

The concentration of chloride ions in sucralose-containing e-liquids at different temperatures.