Analysis of e-liquids for electronic cigarettes using GC-IMS/MS with headspace sampling

Electronic cigarettes (e-cigarettes) are continuously increasing in popularity due to being considered healthier compared with traditional cigarettes. Based on the European directive 2014/40/EU [1] the German legislation restricts the usage of potential harmful substances in these tobacco related products [2,3]. The aim of this work was to establish a method for the detection and quantification of selected substances covered by the above regulation. For this purpose, one-of-a-kind gas chromatograph with ion mobility spectrometer (GC-IMS) was used. Instrument was parallelly coupled with conventional chromatograph equipped with quadrupole mass spectrometer (GC-MS). Headspace (HS) was used as a sample preparation technique. During initial tests both systems were correlated by using a mixture of simple carbonyl compounds. The identification of the selected analytes was performed by mass spectrometry and calibration curves for the quantification were recorded. For all tested substances the limit of detection (LOD) and limit of quantification (LOQ) were determined. The LOD ranges are from 8 to 70 μg/L, the LOQ are from 25 to 200 μg/L. For testing the usability of the developed method 20 samples of commercially available refills for e-cigarettes (e-liquids), produced in Germany and Poland, were analyzed. Substances listed in the directive were found in all samples. In two of them an according to the regulations forbidden substance (estragole) was detected.