Gas-liquid chromatographic determination of major tobacco alkaloids

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.

Development of a Cigarette Tobacco Filler Standard Reference Material

A new tobacco filler Standard Reference Material (SRM) has been issued by the National Institute of Standards and Technology (NIST) in September 2016 with certified and reference mass fraction values for nicotine, N-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and volatiles. The constituents have been determined by multiple analytical methods with measurements at NIST and at the Centers for Disease Control and Prevention, and with confirmatory measurements by commercial laboratories. This effort highlights the development of the first SRM for reduced nicotine and reduced tobacco-specific nitrosamines with certified values for composition.

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.

Chemical fate and genotoxic risk associated with hypochlorite treatment of nicotine

Nicotine, the main alkaloid of tobacco, is a non- prescription drug to which all members of a tobacco-smoking society are exposed either through direct smoke inhalation or through second-hand passive 'smoking'. Nicotine is also commercially available in some pharmaceutical products and is used worldwide as a botanical insecticide in agriculture. Nicotine dynamics in indoor and outdoor environments as well as the human excretions and the manufacturing process are responsible for its entry in the environment through municipal and industrial wastewater discharges. The presence of nicotine in surface and ground waters points out that it survives a conventional treatment process and persists in potable-water supplies. Complete removal of nicotine is instead reported when additional chlorination steps are used. In this paper a simulation of STP chlorination of nicotine and a genotoxic evaluation of its main degradation products are reported. Under laboratory conditions removal of nicotine seems not to be due to mineralization but to transformation in oxidized and chlorinated products. The by-products have been isolated after fractionation by diverse chromatographic procedures and their structures determined using mass spectrometry and (1)H and (13)C NMR spectroscopy. Preliminary genotoxic SOS Chromotests with Escherichia coli PQ37 evidence no toxicity of the products.

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.

Analyses of tobacco alkaloids by cation-selective exhaustive injection sweeping microemulsion electrokinetic chromatography

In this study, an on-line concentration method which coupled cation-selective exhaustive injection (CSEI) sweeping technology with microemulsion electrokinetic chromatography (MEEKC) was used to detect and analyze several tobacco alkaloids (nornicotine, anabasine, anatabine, nicotine, myosmine and cotinine) that are commonly found in various tobacco products. First, the effects of microemulsion compositions (oil, cosurfactant and solution pH) were examined in order to optimize the alkaloid separations in conventional MEEKC. The pH value and the injection length of basic plug were found to be the predominant influences on the alkaloid stacking. This optimal CSEI sweeping MEEKC method provided approximately 180- to 540-fold increase in detection sensitivity in terms of peak height without any loss in separation efficiency when compared to normal MEEKC separation. Furthermore, this proposed CSEI sweeping MEEKC method was applied successfully for the detection of the minor alkaloids nornicotine, anabasine and anatabine in tobacco products.

CE with sequential light-emitting diode-induced fluorescence and electro-chemiluminescence detections for the determination of amino acids and alkaloids

This paper describes the determination of alkaloids and amino acids (AAs) using CE in conjunction with sequential light-emitting diode-induced fluorescence (LEDIF) and electrochemiluminescence (ECL) detections. In the CE-LEDIF-ECL system, the ECL detector was located in the outlet of the capillary, while the LEDIF detector was positioned 12 cm from the outlet. Naphthalene-2,3-dicarboxaldehyde (NDA) was used to form fluorescent AA-NDA derivatives from AAs possessing primary amino groups, while Ru(bpy)(3) (2+) was used to obtain ECL signals for analytes having secondary and tertiary amino groups. In the presence of poly(ethylene oxide), we accomplished the CE-LEDIF-ECL separation of a mixture of 12 AA-NDA derivatives, anabasine, nicotine, and proline within 11 min. This low-cost CE-LEDIF-ECL system allows the analysis of these AA-NDA derivatives and alkaloids at concentrations in the ranges of 49 nM-0.2 microM and 0.66-4.7 microM, respectively. We applied our CE-LEDIF-ECL system to the analysis of a urine sample and also to tobacco extracts. We obtained good qualitative and quantitative results when using this method with these analytes: the RSDs were below 3.0 and 2.8%, respectively. This CE-LEDIF-ECL system provides the advantages of high efficiency, speed, and sensitivity for the analysis of analytes possessing amino groups.

Novel approaches to plant drug discovery based on high throughput pharmacological screening and genetic manipulation

Plants are potentially important for novel therapeutic drug leads, but the slowness of conventional methods for investigation of plants limits enthusiasm in the pharmaceutical industry. To overcome some of the drawbacks, we have applied high throughput pharmacological screening (HTPS) to crude plant extracts. Using a "differential smart screen", (DSS) the spectrum of activity contained in a crude extract is measured at several closely related receptor subtypes. This spectrum is then compared to that of known compounds. A unique spectrum suggests that the extract merits further investigation. Evaluation of species and environmental libraries of whole plants has demonstrated the value of this approach for rapid prioritization of plants for investigation. In addition, genomic and genetic manipulation of plants and plant cell cultures can increase the value of DSS. For example, the whole genomic potential of a plant species for biodiversity can be accessed by using gain of function mutations to generate a "functional genomics library" of mutant clonal cultures, and the bioactivity of these cultures tested by DSS. Clones that overproduce activity differing from the wild-type plant can be identified in this way. This "Natural Products Genomics" (NPG) strategy is limited by the massive numbers of clonal cultures that are required to cover all possible gain-of-function mutations. The rapidity and efficiency of this process can be improved by using transgenic plants expressing appropriate mammalian proteins. These may be designed to make the plant cell resemble a human cell for a specific form of toxicity. Now, "unnatural selection" of resistant mutant clones can be used to provide a sub-population potentially enriched in useful compounds. Alternatively, transgenic plant cells can be used for "in situ screening" in which a mammalian receptor protein, linked to a reporter construct, such as green fluorescent protein, is expressed. Clonal cultures that produce ligands for this receptor can now be rapidly identified visually in an ultra-HTPS. Overall, our aim is to use pharmacological screening, together with functional genomic approaches, to make plant drug discovery competitive with combinatorial chemistry.