(M0930-05-26) Distinguishing Tobacco-Derived Nicotine from Synthetic Nicotine in Commercial Nicotine Samples

Purpose: According to US federal regulations, any product containing tobacco-derived materials is deemed a tobacco product.¹ As such, electronic nicotine delivery systems (ENDS) containing tobacco-derived nicotine (TDN) are deemed tobacco products and subject to FDA’s premarket authorization requirements. To circumvent the FDA Premarket Tobacco Product Application (PMTA)² process for a new tobacco product or as a result of receiving a PMTA Marketing Denial Order, some tobacco-product manufacturers have turned to the use of synthetic nicotine (SN) as a replacement for tobacco-derived nicotine (TDN). This regulatory loophole was being exploited because products containing TDN, and primarily composed of (S)-nicotine, are regulated by the FDA CTP whereas products containing SN were outside of FDA regulation. Because of recent Congressional action granting FDA authority over SN, tobacco-product manufacturers must now submit a PMTA for tobacco products containing SN. Synthetic methodology has presently improved such that synthetic (S)-nicotine with a low level of (R)-nicotine (0.1-0.2%) is now commercially available whereas the tobacco plant produces primarily the (S) enantiomer with a small amount (0.8-0.9%) of the (R) enantiomer. As current development of ENDS and modern oral tobacco products (pouch, lozenges) continues, the need for robust analytical methods to differentiate TDN from SN will be of significant economic and regulatory importance for tobacco product authentication. The purpose of this study was to demonstrate the utility of analytical chromatographic methods to distinguish TDN from SN.

Methods: Analysis of commercial nicotine included four samples of TDN from India and the Philippines from two suppliers, and four samples of SN from four suppliers. Nicotine samples were used as is for sample preparation. Nicotine analysis was done using GC/MS and SPME/GC/MS. (R)- and (S)-nicotine were analyzed using either chiral GC-MS or chiral HPLC-UV. The chiral GC-MS method that was initially developed had a slightly unresolved baseline separation of (S)- and (R)-nicotine and a relatively long run time ( >73 min). The chiral HPLC-UV method improved upon the GC-MS method and provided an excellent enantiomeric separation and a shorter run time ( >10 min).

Results: The chromatographic methods provided data to successfully distinguish TDN from SN and provided additional chemical characteristics of the commercial nicotine samples. Using GC/MS, TDN was found to contain 2.3’-bipyridine as a characteristic tobacco compound not found in SN samples, whereas SN was found to contain the synthetic starting material, ethyl nicotinate and the synthetic impurity, 1-methyl-2-pyrrolidinone. An additional impurity in one sample of SN included 1,3-dichloro-2-propanol, along with the residual solvent, methylene chloride. In some instances, SN was found to contain lower levels of the nicotine oxidation products, myosmine and β-nicotyrine. The TDN samples were found to contain 0.8-0.9% (R)-nicotine by chiral GC/MS and 0.6% by chiral HPLC-UV. SN was found to contain either a 50:50 mixture of (R)- and (S)-nicotine in one sample or a very small amount (0.1-0.2%) of (R)-nicotine in three other samples. This amount is much lower than is typically found in TDN and provides supporting evidence for the determination of SN.

Conclusion: Two achiral chromatography methods and two chiral chromatography methods were used to distinguish TDN from SN. TDN was found to contain the characteristic tobacco compound, 2,3’-bipyridine, while in some instances, SN, was found to contain synthetic starting materials, synthetic impurities, or residual solvents. Chiral chromatography results provided supporting evidence that nicotine containing low levels of (R)-nicotine (0.1-0.2%), as compared to TDN which typically contains 0.8-0.9% (R)-nicotine, were most likely synthetic. The chiral methods provide an approach for determining (S)/(R) nicotine ratios that may be of importance related to any pharmacological concerns and future research. The combination of these analytical methods provides valuable information for distinguishing TDN from SN in commercial nicotine samples.

References: 1. Family Smoking Prevention and Tobacco Control Act, FDA, June 2009.
2. Premarket Tobacco Product Applications, FDA, September 2011.

Acknowledgements:The authors wish to acknowledge the contributions of Ching-En Chou to this poster.


Figure 1. The structure of (S)-Nicotine and (R)-Nicotine.


Table 1. Analytical results for commercially available TDN and SN.
TDN = Tobacco-Derived Nicotine; SN = Synthetic Nicotine; NGL = Next Generation Labs TFN®; eLT (TTI) = e-LiquiTech (Tobacco Technology, Inc.)