Simultaneous quantification of nicotine salts in e-liquids by LC-MS/MS and GC-MS

Nicotine salts, formed by nicotine and organic acids, are commonly added to electronic cigarette liquids for their ability to provide desirable sensory effects. Analytical strategies have been developed to detect the types of organic acids and nicotine levels, but methods for directly measuring nicotine salts are still desirable. Herein, a novel approach is presented for the simultaneous quantification of non-volatile and volatile nicotine salts via liquid chromatography/tandem mass spectroscopy (LC-MS/MS) and gas chromatography/mass spectroscopy (GC-MS). This approach was validated with recovery experiments, which yielded recovery values between 92.0% and 110.8%. This method is the first technique for quantifying multiple nicotine salts that could be present in commercial e-liquids. Without using derivatization steps, different nicotine salts could be detected rapidly and conveniently. This new method was demonstrated with 10 e-cigarette liquid samples, providing satisfactory outcomes. It could be used to study organic acids and protonated nicotine in e-liquids and the release behaviour of nicotine salts in electronic cigarettes.