Abstract
Introduction
Electronic cigarettes (e-cigarettes) have rapidly evolved since their introduction to the U.S. market. The rebuildable atomizer (RBA) offers user-driven modification to the heating element (coil) and wicking systems. Different coil materials can be chosen based on user needs and preferences. However, the heating element of an e-cigarette is believed to be one-source for toxic metal exposure.
Methods
E-cigarette coils from Kanthal and nichrome wires were constructed in a contact and non-contact configuration and heated at four voltages. The maximum temperatures of the coils were measured by infrared temperature sensing when dry and when saturated with 100% vegetable glycerin or 100% propylene glycol. The metal composition of each coil was analyzed with Scanning Electron Microscopy-Energy-Dispersive X-Ray (SEM-EDX) when new, and subsequently after 1, 50, and 150 heat cycles when dry.
Results
The coils reached temperatures above 1000 °C when dry, but were below 300 °C in both liquid-saturated mediums. Metal analysis showed a decrease of 9–19% chromium and 39–58% iron in Kanthal wire and a decrease of 12–14% iron and 39–43% nickel in nichrome wire after 150 heat cycles. Significant metal loss was observed after one heat cycle for both coil alloys and configurations.
Conclusions
The loss of metals from these heat cycles further suggests that the metals from the coils are potentially entering the aerosol of the e-cigarette, which can be inhaled by the user.
Disclosure statement
The authors have no conflicts of interest to disclose.