Determination of tobacco alkaloids by gas chromatography with nitrogen-phosphorus detection

A comparison of nicotine content methods to produce a UPC2-MS2 method for the analysis of nicotine and minor alkaloids in SPECTRUM nicotine research cigarettes

Nicotine is the principal alkaloid in tobacco and has been the primary subject of scientific investigation for its pharmacological effects contributing to tobacco use, dependence, withdrawal, and physical harm. Related minor alkaloids, accounting for less than 6% of alkaloid content in tobacco leaves, may also mirror some of the same pharmacological effects. To detect such low concentrations of the minor alkaloids, tobacco product methods produced by the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) using gas chromatography and flame ionization detection (GC-FID) have been adapted for use with gas chromatography-mass spectrometry (GC-MS). Nicotine and minor alkaloid content in SPECTRUM Nicotine Research Cigarettes (NRC) have previously been determined using GC-FID; however, the minor alkaloids were unable to be detected or quantitated. This study employed UltraPerformance Convergence Chromatography (UPC2) system coupled with tandem mass spectrometry (MS2) to determine the nicotine and minor alkaloid content in NRC tobacco products. CORESTA Recommended Methods (CRMs) were adapted for their sample preparative procedures for optimal extraction followed by detection with UPC2-MS2. These results were compared to two separate CRMs that used GC-FID and GC-MS2 as well as an alternative method with GC-MS2 detection. The GC-FID and GC-MS2 CRM preparations along with the alternative GC-MS2 were unable to detect the analytes in every NRC formulation, whereas the UPC2-MS2 extraction and detection method was able to quantify every analyte in every NRC formulation. This increased sensitivity demonstrates the utility of the UPC2-MS2 analytical method in accurately detecting and quantifying nicotine and minor alkaloids in tobacco filler.

Progress in quantification of nicotine content and form distribution in electronic cigarette liquids and aerosols

Each electronic cigarette (e-cigarette) is a battery-powered system which converts electronic cigarette liquids (e-liquids) into the inhalable phase by heating the solution when it is in use. After four generations of development, e-cigarettes tend to be more customized and user-operable. The main components in the e-liquid and the aerosol are vegetable glycerin, propylene glycol, nicotine, organic acid and some flavor ingredients. Among them, nicotine is closely associated with the irritation and physiological satisfaction caused by tobacco products, and it is the core functional substance of e-cigarettes. For this reason, the quantification of nicotine content and nicotine form distribution mainly focuses on the components of the e-liquid and the released aerosol. Up to now, various technologies and methods have been applied in the analysis and research of nicotine content and nicotine form distribution in the e-liquid and its aerosol. GC-MS is often used as the most viable tool for the analysis of volatile organic compounds and can be widely applied in the measurement of nicotine related chemicals; there are a number of quantitation strategies using LC-MS, LC-MS/MS or ¹H NMR for the analysis of e-cigarette samples. We also reviewed the four main methods for determining the distribution of nicotine forms, which are pH value derivation, solvent extraction, SPME and NMR methods. These research methods are of great significance to the upgrading and development of e-cigarette products.

Determination of Nicotine-Related Impurities in Nicotine Pouches and Tobacco-Containing Products by Liquid Chromatography–Tandem Mass Spectrometry

Smokeless tobacco products and nicotine-containing tobacco-free oral pouches have increased in popularity in recent years. They are associated with far fewer health hazards compared to cigarettes. Nicotine pouches are filled with non-tobacco filler and nicotine. The nicotine used in nicotine pouches usually comes from the extraction of tobacco; thus, related alkaloids may be found as impurities at low levels. Moreover, nicotine degradation products are formed because of microbial action, flavor oxidation, exposure to high temperatures etc. Currently, there are no published or recommended methods for the analysis of nicotine degradants in nicotine pouches. Here, we present a sensitive and selective liquid chromatography–tandem mass spectrometry method for the simultaneous determination of seven nicotine-related impurities. All seven analytes and corresponding deuterated internal standards were separated within 3.5 min, including 1 min equilibration. The method was fully validated, showing good linearity with correlation coefficients >0.996 for all analytes, good extraction yields ranging from 78% to 110%, limits of detection between 0.08 and 0.56 µg/g and limits of quantification between 0.27 and 2.04 µg/g. Although the method was mainly developed to determine the degradants of nicotine in nicotine pouches, it was validated and performed well on a broader range of tobacco-containing products.

Simultaneous determination of six alkaloids in tobacco and tobacco products by direct analysis of real-time triple quadrupole mass spectrometry with a modified pretreatment method

In order to determine six alkaloids (mass fraction) of nicotine, nornicotine, myosmine, anatabine, anabasine, and nicotyrine in tobacco and tobacco products quickly, accurately, and simultaneously, a novel method based on direct analysis of real-time model in situ ionization technique combined tandem mass spectrometry with a modified sample pretreatment was established, in which experimental parameters such as the type and amount of extraction solvent and injection rate were optimized, respectively. The samples of five commercial cigarettes and five kinds of tobacco leaves were analyzed by the established method, and the determined values were compared with those obtained using a gas chromatography with mass spectrometry method: (1) Under optimized conditions (30 mL ultrapure water as extraction solvent and with extraction rate of 0.6 mm/s), analysis could be completed within 10 min. (2) The linear range of the method was 0.002-2000 μg/g withR 2 = 0.9957 , the recovery ranged from 86.8 to 105.6%, and the limit of detection and the limit of quantification were 0.004-0.835 μg/g and 0.013-2.787 μg/g, respectively. (3) The relative standard deviation between direct analysis of real-time method and the gas chromatography with mass spectrometry method was 0.34-8.83%. The established method is rapid, reliable, and suitable for the ultrafast determination of six alkaloids in tobacco and tobacco products.

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

E-liquid manufacturers are under scrutiny concerning the purity and concentration accuracy of nicotine and the minor nicotine-related alkaloids (NRAs) packaged in their products. In this communication we report concentrations of nicotine and five NRAs (nornicotine, cotinine, anabasine, anatabine, myosmine) from locally purchased E-liquids.

METHODS

Five brands of E-liquids (three bottles each) were purchased locally. Additionally, three bottles of reference E-liquid were prepared. Concentrations of nicotine and NRAs from each bottle were measured by HPLC. Concentrations of these alkaloids were also determined from electronic cigarette-generated aerosol and traditional cigarette smoke.

RESULTS

Nicotine concentrations in E-liquid brands 1, 2, 3, 4, 5 and in the reference E-liquid were 17.8 ± 4.1, 23.2 ± 0.7, 24.0 ± 0.9, 24.9 ± 0.2, 19.7 ± 0.3 and 20.4 ± 0.1 mg/mL, respectively. Concentrations normalized to 100% of product label were 74%, 97%, 100%, 104%, 109% and 102%, respectively. E-liquid brand 1 showed significance (p < 0.001) between bottles, while the reference showed the least variability. Similar results were obtained for the NRAs. Results also indicated the NRAs in aerosol of the reference E-liquid are lower than in cigarette smoke.

CONCLUSIONS

The amounts of NRAs present in E-liquids and E-liquid aerosol are less compared to cigarettes, however, inconsistencies and variation in nicotine concentrations supports the need for regulatory oversight.

Gas Chromatography-Mass Spectrometry Method for Simultaneous Detection of Nine Alkaloids in Tobacco and Tobacco Products by QuEChERS Sample Preparation

One method based on QuEChERS sample preparation is presented in this study, which leads to simultaneously detect nine alkaloids in tobacco and tobacco products. Nicotine, nornicotine, myosmine, N-methyl anabasine, β-nicotyrine, anabasine, anatabine, isonicotenine and cotinine can all be found in fresh tobacco leaves, cigars, Virginia-type and blended-type cigarettes. The samples were purified via a certain proportion of adsorbents consisting of anhydrous magnesium sulfate, PSA and carbon after extracting, then centrifuged and filtered before analyzing by GC-MS. The matrix effects were all among 88 - 105%. The limit of detection of all were within the range of 0.0065 - 0.1509 μg/g and limit of quantification were among 0.0217 - 0.5031 μg/g. The recovery rates were higher than 89%. This is the first time that the QuEChERS sample preparation method has been applied for tobacco alkaloids, where more varieties of alkaloids could be quantified regarding sensitivity and reproducibility.

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.

A reversed-phase HPLC-UV method developed and validated for simultaneous quantification of six alkaloids from Nicotiana spp

A reversed-phase HPLC-UV method was developed, optimized, and validated for the separation and quantitation of six target alkaloids from leaves of Nicotiana species (nicotine, nornicotine, anatabine, anabasine, myosmine, and cotinine). A bidentate reversed-phase C18 column was used as stationary phase and an alkaline ammonium formate buffer and acetonitrile as mobile phase. The alkaloids were well separated in a short run time of 13min with mobile phase pH 10.5 and a small gradient of 9-13% acetonitrile, and detected using UV at 260nm. Peak parameters were acceptable for all six closely related alkaloids. The proposed method has enough linearity with correlation coefficient >0.999 within the investigated range for all tested alkaloids. Satisfactory precision was achieved for both intra- and inter-day assay, with RSD less than 2% for all alkaloid standards. Reproducibility was also within the acceptable range of RSD <2%. Limit of detection was 1.6μg/mL for nicotine and below 1μg/mL for all other alkaloids. The limit of quantification was 2.8 and 4.8μg/mL for nornicotine and nicotine respectively, and below 2μg/mL for all other alkaloids. The method was successfully applied for simultaneous analysis of alkaloids in leaves of Nicotiana benthamiana.

Protonating and determining myosmine intactly by association with citrate anion

Myosmine can not be separated from nornicotine, nicotine and anabasine intactly by capillary zone electrophoresis (CZE) with a phosphate buffer. Using citrate solution at pH 6.5 as a CZE buffer, myosmine is protonated intactly by H(+), charged positively and then separated from other tobacco alkaloids on the baseline. Its sensitivity is ten times higher than gas chromatography (GC) with a nitrogen-phosphorus detector (NPD). The mechanism for protonating myosmine intactly is discussed and the utility of the new method is testified, too.

Validation of a GC-FID method for rapid quantification of nicotine in fermented extracts prepared from Nicotiana tabacum fresh leaves and studies of nicotine metabolites

A new GC-FID method, which allows rapid and reliable quantitation of nicotine in tobacco leaf extracts, was developed and validated. To avoid nicotine adsorption on the column, an amine-deactivated capillary column was used. The method developed was applied to study the degradation of nicotine in a fermented aqueous extract, and a loss of nearly 20% of nicotine over 12 months was observed. Careful inspection of GC-MS runs from concentrated samples of the same extract revealed the presence of nicotine metabolites such as nornicotine, anatabine, myosmine, 2,3'-bipyridyl, and 2-pyrrolidinone.

Cigarette smoke chemistry market maps under Massachusetts Department of Public Health smoking conditions

This study extends the market mapping concept introduced by Counts et al. (Counts, M.E., Hsu, F.S., Tewes, F.J., 2006. Development of a commercial cigarette "market map" comparison methodology for evaluating new or non-conventional cigarettes. Regul. Toxicol. Pharmacol. 46, 225-242) to include both temporal cigarette and testing variation and also machine smoking with more intense puffing parameters, as defined by the Massachusetts Department of Public Health (MDPH). The study was conducted over a two year period and involved a total of 23 different commercial cigarette brands from the U.S. marketplace. Market mapping prediction intervals were developed for 40 mainstream cigarette smoke constituents and the potential utility of the market map as a comparison tool for new brands was demonstrated. The over-time character of the data allowed for the variance structure of the smoke constituents to be more completely characterized than is possible with one-time sample data. The variance was partitioned among brand-to-brand differences, temporal differences, and the remaining residual variation using a mixed random and fixed effects model. It was shown that a conventional weighted least squares model typically gave similar prediction intervals to those of the more complicated mixed model. For most constituents there was less difference in the prediction intervals calculated from over-time samples and those calculated from one-time samples than had been anticipated. One-time sample maps may be adequate for many purposes if the user is aware of their limitations. Cigarette tobacco fillers were analyzed for nitrate, nicotine, tobacco-specific nitrosamines, ammonia, chlorogenic acid, and reducing sugars. The filler information was used to improve predicting relationships for several of the smoke constituents, and it was concluded that the effects of filler chemistry on smoke chemistry were partial explanations of the observed brand-to-brand variation.

Selective determination of pyridine alkaloids in tobacco by PFTBA ions/analyte molecule reaction ionization ion trap mass spectrometry

The application of perfluorotributylamine (PFTBA) ions/analyte molecule reaction ionization for the selective determination of tobacco pyridine alkaloids by ion trap mass spectrometry (IT-MS) is reported. The main three PFTBA ions (CF(3)(+), C(3)F(5)(+), and C(5)F(10)N(+)) are generated in the external source and then introduced into ion trap for reaction with analytes. Because the existence of the tertiary nitrogen atom in the pyridine makes it possible for PFTBA ions to react smoothly with pyridine and forms adduct ions, pyridine alkaloids in tobacco were selectively ionized and formed quasi-molecular ion [M + H](+)and adduct ions, including [M + 69](+), [M + 131](+), and [M + 264](+), in IT-MS. These ions had distinct abundances and were regarded as the diagnostic ions of each tobacco pyridine alkaloid for quantitative analysis in selected-ion monitoring mode. Results show that the limit of detection is 0.2 microg/mL, and the relative standard deviations for the seven alkaloids are in the range of 0.71% to 6.8%, and good recovery of 95.6% and 97.2%. The proposed method provides substantially greater selectivity and sensitivity compared with the conventional approach and offers an alternative approach for analysis of tobacco alkaloids.

Application of nicotine enantiomers, derivatives and analogues in therapy of neurodegenerative disorders

This review gives a brief overview over the major aspects of application of the nicotine alkaloid and its close derivatives in the therapy of some neurodegenerative disorders and diseases (e.g. Alzheimer's disease, Parkinson's disease, Tourette's syndrome, schizophrenia etc.). The issues concerning methods of nicotine analysis and isolation, and some molecular aspects of nicotine pharmacology are included. The natural and synthetic analogues of nicotine that are considered for medical practice are also mentioned. The molecular properties of two naturally occurring nicotine enantiomers are compared--the less-common but less-toxic (R)-nicotine is suggested as a natural compound that may find its place in pharmaceutical practice.

Fast analysis of nicotine in tobacco using double-shot pyrolysis--gas chromatography--mass spectrometry

A simple, rapid, and sensitive assay of nicotine in tobacco has been developed using pyrolysis-gas chromatography-mass spectrometry (DSP-GC-MS). The optimum pyrolyzer (desorption) conditions, using Korean tobacco grade B1O (0.4 mg) and n-heptadecane as an internal standard, were found to be heating from 50 to 300 degrees C at a rate of 60 degrees C/min. Replicate determinations (n = 5), on the same tobacco and using n-heptadecane as the internal standard, resulted in a nicotine content of 1.96%, with a relative standard deviation (RSD) of 1.9%. This result was in good agreement with those from established methods: the Cai ether extraction method, a chloroform extraction method, and the CORESTA recommended method. However, the DSP method requires less than half the time of the solvent extraction methods, requires less sample, is almost solvent-free, and is less labor-intensive. The DSP method was used to determine the nicotine content of eight flue-cured tobaccos from Brazil, China, Korea, and the United States, which were found to have contents ranging from 1.21 to 2.19%.