Analysis of Nicotine and Nicotine-Related Compounds in Electronic Cigarette Liquids and Aerosols by Liquid Chromatography-Tandem Mass Spectrometry

Abstract

SUMMARYThe objective of this study was to develop and validate an analytical method for determining nicotine and nicotine related compounds (i.e., nicotine-N-oxide, cotinine, nornicotine, anatabine, myosmine, anabasine, and β-nicotyrine) in e-cigarette aerosols and e-liquids. Aerosol collection was achieved using a Cambridge collection pad. The sample preparation consisted of adding deuterated internal standards to the collection pad and extracting with 100 mM ammonium acetate solution using a wrist-action shaker. The filtrate was then analyzed by LC-MS/MS using a Gemini NX C 18 column (3 µm, 150 × 3 mm) with a mobile phase gradient system consisting of acetonitrile and 10% acetonitrile in 10 mM ammonium bicarbonate (pH = 8.0) and electrospray ionization (ESI) in the positive mode. The e-liquid was analyzed using the same instrumental parameters, but simplifying the sample preparation procedure by adding deuterated internal standards directly to the 100-mg sample. The sample was then extracted with 100 mM ammonium acetate solution, sonicated, and filtered. In this study, the method's accuracy, robustness, and reliability were enhanced by using deuterated analogues of each compound as internal standards and by applying two ion-transition pairs for each compound for the confirmation and quantification. Validation experiments demonstrated good sensitivity, specificity and reproducibility. All the target compound calibrations exhibited satisfactory linearity from 0.050 to 5.0 mg/mL (r 2 > 0.995). The average recoveries for e-liquids varied from 85.2%(nicotine-N-oxide) to 110% (β-nicotyrine) with recoveries for all compounds exhibiting a coefficient of variation (CV) < 5.0%. Similarly, the average recoveries for e-cigarette aerosols varied from 87.8% (for nicotine-N-oxide) to 111% (for myosmine) with all CV < 8.8%. The LOD and LOQ for e-liquids for all target compounds ranged from 0.234 and 0.781 μg/g (cotinine) to 1.66 and 5.48 μg/g (nicotine-Noxide). For e-cigarette aerosols these limits ranged from 0.094 and 0.312 μg/collection (cotinine) to 0.872 and 2.87 μg/collection (nicotine-N-oxide). This methodology was used to quantitatively determine if any of the target compounds were present in a variety of sample matrices, including e-cigarette solutions and aerosols, and was successfully applied to stability studies, to monitor changes in the target compound levels which might be caused by e-cigarette formulations, components and the storage conditions. [Beitr. Tabakforsch. Int. 27 (2017)

The Use of HPLC-PDA in Determining Nicotine and Nicotine-Related Alkaloids from E-Liquids: A Comparison of Five E-Liquid Brands Purchased Locally

“…In addition, using a methanol extraction procedure, concentrations of all alkaloids in aerosol and smoke were determined. The results of this study confirm the work of others [1,9,16,17] who indicated that NRAs in E-liquid and ECIG-generated aerosol are in substantially lower levels than in cigarettes and conventional cigarette smoke. The advantage of the methodology used in this study is that the extraction procedure for aerosol and smoke, although less efficient in terms of percent recovery, is simple (i.e., few methodological steps), clean (i.e., reduced noise and interference in the chromatographic analysis) and fast (i.e., <2 hours/sample) and HPLC-PDA can accurately measure NRAs at extremely low levels.…”

A Standardized Approach to Quantitative Analysis of Nicotine in e-Liquids Based on Peak Purity Criteria Using High-Performance Liquid Chromatography

“…Based on published literature, earlier HPLC analytical methods have been developed for analysis of nicotine from e-liquids by reversed phase chromatography using a C18 column [ 11 , 12 , 18 ]. Some references for LC-MS method also describe use of a C18 column for separation of nicotine from other ingredients in e-liquids [ 13 , 14 ]. Therefore, a C18 column was initially used for nicotine analysis.…”

An Analytical Perspective on Determination of Free Base Nicotine in E-Liquids

“…Considering the addictive nature of nicotine, e-liquids need to be regulated for the total nicotine content as well as free base nicotine yield. ere are published methods for determining total nicotine content in e-liquids using gas chromatography and liquid chromatography coupled with mass detectors [27][28][29]. Recently, we have proposed a HPLC method based on peak purity criteria for accurate quantification of total nicotine content [19].…”