An analytical method for simultaneous determination of various metals in e-cigarette aerosol using inductively coupled plasma mass spectrometry (ICP-MS) was reported at the CORESTA Congress in 2016. In the presence of propylene glycol and glycerol excessive recovery rates for specific metals, including arsenic (As) and selenium (Se), were found, most likely caused by matrix effects.

Different techniques could be applied to reduce the observed matrix effects whilst analysing As and Se in e-liquids. The purpose of this study is to show different approaches towards the reduction of matrix effects for the determination of As and Se in e-liquids.

Two different approaches to reduce the beforehand described matrix effect were investigated. The first approach was to use tellurium (Te) with a very similar ionisation potential like As and Se as an internal standard to quantify As and Se. The second approach was to add a low concentration of methanol to the calibration standards.

E-liquid samples prepared with propylene glycol and/or glycerol and containing small amounts of metals were diluted with 5 % nitric acid. Scandium (Sc), thallium (Tl) and either yttrium or Te as internal standards were added to both e-liquid samples and calibration standards to investigate the first approach.

To investigate the second approach, calibration standards each containing a small amount of methanol were prepared. In this approach, Sc, Tl and Te as internal standards were added to both e-liquid samples and calibration standards.

The samples and standards were analysed by ICP-MS equipped with a collision/reaction cell, and the recovery rates of the metals were calculated. Both approaches showed significantly improved As and Se recovery rates.