Analysis of Toxic Metals in Electronic Cigarette Aerosols Using a Novel Trap Design

Abstract

Since 2006 the domestic popularity and sales of electronic cigarettes (i.e., electronic nicotine delivery systems or ENDS) have grown rapidly. Although the constituents of the aerosol produced by ENDS have been previously investigated, differences in puff regimens and aerosol trapping schema in published literature often complicate result comparisons and data interpretation. As the ENDS product designs continue to evolve, there is a critical need to develop and validate robust methodologies for laboratory testing, appropriate aerosol generation and trapping media required for accurate determinations of ENDS aerosol metals deliveries. A simple, high metals purity, fluoropolymer trap was developed and validated that meets standard machine puffing regimen (CORESTA Recommended Method 81) specifications and exhibits negligible acid extractable metal backgrounds. Using a standard machine puffing regimen in combination with a fluoropolymer condensation trap, aerosol was generated and collected from select ENDS devices for analysis of chromium, nickel, copper, zinc, cadmium, tin, and lead with triple quadrupole inductively coupled plasma mass spectrometry. Devices tested spanned a range of commercial products, including flavored variants of JUUL pods, refillable tank systems, rechargeable cartridges, and single-use ENDs devices. Results showed that for aerosols generated under a fixed puffing regimen (50 puffs/collection), metal concentrations ranged from below the detection limits (LOD) to 614 ng copper and 339 ng zinc per 10 puffs. Cadmium concentrations were below LOD for all devices tested. Device specific aerosol levels of Sn and Pb ranged from below LOD to low nanogram levels. Cr and Ni were transported in aerosols at levels equivalent to, or slightly higher than in mainstream cigarette smoke using a standard smoking regimen. The generally lower levels of specific metals, Cd and Pb, transmitted in ENDS aerosols compared to mainstream cigarette smoke reflect possible reduction of harm for smokers who substitute the use of ENDS as cessation devices in place of smoking cigarettes.

Analysis of Toxic Metals in Liquid from Electronic Cigarettes

“…Measurable cadmium has been reported in ENDS liquids [7] and in manuscripts on metals in aerosol [12,13]. However, there are no ENDS devices for which cadmium has been reported as a device component, nor did our SEM-EDS, liquid results, or previously reported aerosol results [3] determined detectable cadmium.…”

“…The studies showed that metals significantly increased after contact with a device and concluded that the devices transfer metals to the liquid. The My Vapor Store liquid was added to a Joyetech eGo tank system in our previous study, and the aerosol showed detectable nickel, copper, zinc, tin, and the highest of the analyzed lead [3].…”

“…The major remaining question is whether elevated metals concentrations in ENDS liquids results in higher metals concentrations in the device aerosols. Table 8 compares the brands with the highest copper and zinc concentrations from our previously published data on metals in ENDS aerosols [3] with the liquid concentrations in the same brands. Unless otherwise noted, aerosol results were reported in triplicate, as previously described [3].…”

“…Table 8 compares the brands with the highest copper and zinc concentrations from our previously published data on metals in ENDS aerosols [3] with the liquid concentrations in the same brands. Unless otherwise noted, aerosol results were reported in triplicate, as previously described [3]. Aerosol was collected from an aerosol machine into a novel trap and rinsed with an acid solution.…”

“…Exposure among youth and other users to toxic metals and other ENDS toxicants is not well studied but is of great importance. We previously published the results of aerosol analyses from various ENDS devices for the same seven toxic metals using a high purity fluoropolymer trap to avoid metals contamination [3]. With a few exceptions, low metal concentrations were found in the aerosol.…”