Identification of amino-tadalafil and rimonabant in electronic cigarette products using high pressure liquid chromatography with diode array and tandem mass spectrometric detection

A high-pressure liquid chromatography-diode array detection and multi-mode ionization tandem mass spectrometry (HPLC-DAD–MMI-MS/MS) method was used to identify amino-tadalafil and rimonabant in electronic cigarette (e-cigarette) cartridges. Amino-tadalafil is a drug analogue of the commercially approved Cialis™ (i.e. tadalafil). Rimonabant is a drug that was, at one time, approved for weight loss in Europe (although approval has been retracted), but not in the United States. In addition, poor quality control over the e-cigarette products analyzed here is shown by the presence of nicotine in products labeled as containing no nicotine or by the presence of significant amounts of rimonabant oxidative degradant in e-cigarette products containing rimonabant. Identification was accomplished by comparing the retention time of relevant peaks in the sample with those of standard compounds, in addition to comparison of the UV spectra, mass spectra and/or product ion mass spectra.