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TSRC, Tob. Sci. Res. Conf., 2022, 75, abstr. 30

Analytical method validaiton for analysis of metals in electronic nicotine delivery system liquids without the use of microwave digestion

KING C.; STOGNER D.; ADAMS C.J.; CHOUCHANE S.
Eurofins Professional Scientific Services, Winston-Salem, NC, USA

Analytical evaluation of metals in e-liquid is critical for the assessment of ENDS products. Without using a microwave digestion procedure, e-liquid samples can be prepared for analysis by a simple dilution method. Approximately 1 gram of e-liquid is weighed into a digestion cup, to which, an aliquot of purified water, nitric acid and internal standard is added. Full dissolution of the sample is ensured over 60 minutes with intermittent shaking. The metals of interest are aluminum, cobalt, chromium, copper, iron, nickel, titanium, zinc, silver, cadmium, tin, lead, mercury and arsenic. The method is performed on Perkin Elmer Inductively Coupled Plasma Mass Spectrometry (ICP MS) instruments (NexION 300, 350, and 2000) with a radio frequency (RF) power of 1600. The elements were also analyzed using three modes: standard, dynamic reaction cell (DRC), and kinetic energy discrimination (KED). Standard mode is when no reaction gas is added, DRC is when ammonia gas is introduced and KED is when helium gas is introduced. This method uses Germanium-74, Gallium-71, Indium-115, Bismuth-209 as internal standards. Aluminum, cobalt, chromium, copper, iron, nickel, titanium, and zinc are paired with gallium-71. Silver, cadmium, and tin are paired with indium-115. Lead and mercury are paired with bismuth-209. Lastly, arsenic is paired with germanium-74. The method is fit for the intended purpose and was validated for the following parameters: sample stability, LOD/LOQ, Specificity/Selectivity, Precision, Intermediate Precision, Accuracy, and Robustness. The results of the method validation will be reported.