Simultaneous determination of alkaloids and their related tobacco-specific nitrosamines in tobacco leaves using LC-MS-MS

Tobacco alkaloids (e.g., nicotine) and their metabolized tobacco-specific nitrosamines (TSNAs) are very important compounds for tobacco quality and safety. A simple and specific liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of eight tobacco alkaloids and their related four TSNAs in tobacco leaves. The milled tobacco was extracted using 0.1 mol/L ammonium acetate solution and purified using methanol. Mass spectrometry parameters including declustering potential and collision energy were optimized to ensure that both the TSNAs and the tobacco alkaloids have suitable responses. Recoveries for accuracy were in the range of 80.2-105.2%. Intra-day and inter-day repeatability were in the range of 1.7-12.1% and 6.4-18.7%, respectively. Limit of detection and limit of quantitation were estimated in the range of 6 ng/g-45 μg/g and 24 ng/g-90 μg/g, respectively. The established method was applied to investigate the distribution of tobacco alkaloids and TSNAs in four kinds of tobacco. The result showed that the burley and the flue-cured have the highest (0.00047%) and the lowest (0.000024%) percentage of transformation from alkaloids to TSNAs, respectively. Thus, this method can be used for a wide range of samples.