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Xiang Z.,Guizhou Academy of Tobacco Science | Cai K.,Guizhou Academy of Tobacco Science | Liang G.,Key Laboratory of Molecular Genetics | Zhou S.,Guizhou Academy of Tobacco Science | And 3 more authors.
Analytical Methods | Year: 2014

A method suitable for qualitative and quantitative analysis was developed and validated for volatile flavour components in flue-cured tobacco. The samples were prepared with headspace solid-phase microextraction (HS-SPME) and analyzed by comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-TOFMS). Important experimental parameters, such as the column combinations, the type of SPME fibres and headspace temperatures, were optimized to improve separation and precision. The results showed that divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre at a headspace temperature of 70 °C, along with DB-1MS and DB-wax columns were the best conditions. The 93 compounds of interest were identified and quantified by the match factor and internal standard phenylethyl acetate and the relative standard deviation for most compounds was less than 22.7%. Finally, the developed analytical method was applied to the classification of different flue-cured tobacco samples from different geographical origins and satisfactory results were achieved. © the Partner Organisations 2014. Source


Cai K.,Guizhou Academy of Tobacco Science | Zhao H.,Guizhou Academy of Tobacco Science | Xiang Z.,Guizhou Academy of Tobacco Science | Cai B.,Guizhou Academy of Tobacco Science | And 3 more authors.
Analytical Methods | Year: 2014

To evaluate the glycoconjugated aroma compounds of three cultivars of tobacco, an enzymatic hydrolysis method followed by gas chromatography-mass spectroscopy (GC-MS) was successfully established using a series optimization approach. In the first step, two hydrolytic enzymes were compared and β-glucosidase was chosen. Then, the critical variables that affect the concentration of aglycons were searched by Plackett-Burman design (PBD) and further optimized by central composite design (CCD) of response surface methodology. The optimum conditions were: 60 h for hydrolysis time, 36.8 °C for hydrolysis temperature, 5.6 for pH, 2.1 mL for solvent volume, 2 mg mL -1 for β-glucosidase concentration and 200 rpm for agitation speed. Under the optimized experimental conditions, this method gave a satisfactory precision and linearity with relative standard deviation (RSD) less than 20% and Pearson correlation coefficients greater than 0.99. Finally, the proposed method was successfully employed to analyze flue-cured tobacco (FCT), sun-cured tobacco (SCT) and oriental tobacco (OT). Most of the aglycons were significantly different in the three cultivars and the corresponding characteristic components were discussed in detail. This journal is © the Partner Organisations 2014. Source


Cai K.,Guizhou Academy of Tobacco Science | Xiang Z.,Guizhou Academy of Tobacco Science | Pan W.,Guizhou Academy of Tobacco Science | Zhao H.,Guizhou Academy of Tobacco Science | And 4 more authors.
Journal of Chromatography A | Year: 2013

Glycosidically bound aroma compounds in three different types of tobacco were investigated. After isolation of extracts obtained by Amberlite XAD-2 adsorption and ethyl acetate elution, glycosides were analyzed after enzymatic hydrolysis by gas chromatography-mass spectrometry (GC-MS) or directly after trifluoroacetylated (TFA) derivatization by GC-MS in electron ionization (EI) and negative chemical ionization (NCI) mode. In total 21 bound aglycones were identified by β-glucosidase hydrolysis. These aglycones mainly consisted of C13-norisoprenoids, aromatic components and sesquiterpenoids. Additionally, with the aid of enzymatic hydrolysis, 15 β- d-glucopyranosides and 1 β- d-rutinoside were tentatively identified by TFA derivatization. TFA method was validated by repeatability and successfully employed to analyze different types of tobacco. Principal component analysis (PCA) was carried out on identified glycoside variables to visualize the difference between the tobacco types and the relationship between the glycoside variables and the tobacco types was established. © 2013 Elsevier B.V. Source


Cai K.,Guizhou Academy of Tobacco ScienceGuiyang | Cai B.,Guizhou Academy of Tobacco ScienceGuiyang | Xiang Z.,Guizhou Academy of Tobacco ScienceGuiyang | Zhao H.,Guizhou Academy of Tobacco ScienceGuiyang | And 5 more authors.
Journal of Separation Science | Year: 2016

Polyamines are ubiquitous polycationic molecules that play a key role in many biological processes such as nucleic acid metabolism, protein synthesis, cell growth, and nicotine synthesis precursors. This work describes a rapid, sensitive, convenient, green, and cost-effective method for the determination of polyamines in Nicotiana tabacum by ultra high performance liquid chromatography with photodiode array detection. The analytes were derivatized with 3,5-dinitrobenzoyl chloride at low temperature (about 4°C) and then extracted with vortex-assisted liquid–liquid microextraction. The experimental designs based on quarter-fractional factorial design and Doehlert design were used to screen and optimize the important factors in microextraction process. Under the optimal conditions, the method was linear over 0.05–8.00 μg/mL with an r2 ≥ 0.992 and exhibited good repeatability and reproducibility less than 6.0 and 6.9%, respectively. The limit of detection ranged between 0.013 and 0.029 μg/g. The newly developed method was successfully employed to analyze different leaf samples of Nicotiana tabacum, among which the polyamines contents were found to be very different. Moreover, tyramine, 1,3-diaminopropane, homospermidine, and canavalmine were tentatively identified with the electrospray ionization quadrupole time-of-flight mass spectrometry. To our knowledge, this is the first report of identification of canavalmine in Nicotiana Tabacum. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Source


Xiang Z.,1 Guizhou Academy of Tobacco Science | Cai K.,1 Guizhou Academy of Tobacco Science | Zhou S.,Key Laboratory of Molecular Genetics | Geng Z.,Key Laboratory of Molecular Genetics | Pan W.,1 Guizhou Academy of Tobacco Science
Journal of Separation Science | Year: 2015

A method involving comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry was developed and applied to the analysis of nitrogenous organic compounds present in mainstream cigarette smoke trapped on self-designed equipment. The samples were prepared using low-temperature solvent extraction under liquid nitrogen and analyzed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry. Important experimental parameters, such as the type and volume of the extraction solvent and flow rate of smoking, were optimized to improve the analysis parameter. The results indicated that 180 mL of diethyl ether in the low-temperature solvent extraction apparatus system with a 4 mL/min smoke flow rate were the optimal conditions. Then, 85 nitrogenous organic compounds were identified and quantified using a mass spectral library search, accurate mass ion and N-rules of a molecular formula for nitrogen compounds. Finally, a comparison of the low temperature solvent extraction method and Cambridge filter pad method indicated that more peaks, a higher peak volume and better repeatability were obtained using the low-temperature solvent extraction method. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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