Samples analysed by ICP-MS are typically subjected to a mineralisation/oxidation process to completely dissolve all elements. Therefore, samples are digested using an acid matrix in a block digestor or microwave. During this process, the organic sample content is decomposed into carbon dioxide, which is subsequently removed from the sample. However, if residual carbon is present, the instrument sensitivity can increase significantly. Especially elements with high ionization potential such as selenium (Se), arsenic (As) or beryllium (Be), are susceptible to this phenomenon known as signal enhancement or carbon effect. As a result, quantities of some elements in e-liquids or aerosols of e-cigarettes and recoveries in fortified samples might be overestimated and vary according to the carbon content of the sample.

The decomposition process of reactive samples (e.g. fats, oils) is exothermic and the reaction kinetics are to be monitored carefully. Slow heating rates can help to decompose a sample safely but result in longer sample handling time. Hence, avoiding a digestion step is saving time, reducing the risk of contaminations and eliminating a potential safety hazard.

Herewith, we present a novel approach to overcome matrix effects while analysing e-liquids or aerosols of e-cigarettes without prior digestion. By adding a significant amount of methanol to all standards as well as the sample solution, the signal enhancement effect is matched and does not influence quantification. Introduction of such high amounts of organic solvent is made possible by aerosol dilution systems which are present in modern ICP-MS systems. Variable carbon contents in the samples do not have to be taken into account and recoveries of, for example, a range from 94.9-105.1 %. As a result, a simple, reliable and robust method for the determination of numerous elements in e-liquids as well as aerosols of e-cigarettes has been developed and validated.