Flavors, additives and nicotine levels detected among the most popular e-cigarette refill liquids across 9 European countries after the implementation of Tobacco Products Directive (TPD)

Introduction Data on the flavors and additives content of the electronic cigarette liquids are scarce. This study aimed to identify, record and evaluate flavor and additive content of e-liquids. Methods Within the Horizon2020, EUREST-PLUS study and during the post TPD sample selection period, we purchased in total 137 e-liquids from France, Poland, Germany, the Netherlands, United Kingdom, Spain, Romania, Hungary and Greece. These products included all e-liquids selected in the pre TPD period still available in the market and all the products that were in the top rank during the post TPD period. A quantitative and qualitative chemical analysis was performed using a head space solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GCMS) and liquid chromatography-mass spectrometry method. Results The GCMS analysis using two mass spectral libraries (NIST, WILEY) revealed that more than 247 compounds were present in the examined e-liquid samples. The chemical compounds most frequently detected were: menthol (57.66%), nonanal (53.28%), ethyl maltol (35.77%), linalool (25.55%) beta damascene (24.09%) and ethyl vanillin (24.09%). From the quantitative analysis of the flavor, the mean % w/w content for menthol was 0.0474, for linalool 0.0121, for beta damascene 0.0082, b-ionone 0.003, for a-ionone 0.0037, for ethyl hexanoate 0.0041, alpha damascene 0.0043, for limonene 0.0019 , for a-terpinolene 0.0005 , for methyl cyclopentanolone 0,1536, for acetyl pyrazine 0,0207, for 2,5 dimethylpyrazine for 0,0027, for ethyl maltol for 0,2979, for 3,4 dimethoxy benzaldehyde 0,0116 and for ethyl vanillin 0,1646. Conclusions Our evaluation revealed that after the implementation of TPD and specifically Article 18 where it is clearly stated that additives that increase carcinogenic, mutagenic and reprotoxic properties in unburnt form, addictiveness and toxicity should also be prohibited, stricter policies and monitoring on the flavors and additives are still necessary