Alkaloids proportion and content in and sensory quality of flue-cured tobacco from Hunan province were evaluated and analyzed to study relationship between alkaloids content and sensory quality.Results showed that 1) significant difference existed among leaf positions in alkaloid content and proportion.Nicotine,nor-nicotine,anatabine,anabasine,total alkaloids, nor-nicotine/total alkaloids ratio,anatabine/total alkaloidsratio,anabasine/total alkaloids ratio and nicotine transforrmation ratio gradually increased from lower to upper position,but nicotine/total alkaloid ratio was the opposite;2) linear and nonlinear correlation analysis showed that the relationships of nicotine and smoke concentration,nicotine and aftertaste,and total alkaloids, did not reach statistically significant level.However,there were statistically significant non-linear relationships between nicotine,nor-nicotine,anatabine,anabasine,total alkaloids and aroma quality;3) the relationships of tobacco alkaloid content and smoking quality can be fully revealed by smoothing spline regression analysis.

A polt experiment was used to study on the composition and the content of volatile,non-volatile,and higher fatty acids in different flue-cured tobacco varieties including K326,Yunyan85,Yunyan87 and Hongda.The results showed that the content of organic acid in different flue-cured tobacco varieties exited K326Yunyan85Yunyan87Hongda;Hongda contained more volatile acids,especilly 3-methy valeric acid,but the high fatty acid saturation and the content of non-volatile,higher fatty acids were low.K326 contained more volatile and non-volatile acids,especilly isobutyric acid and malic acid;the higher fatty acids was low,but the high fatty acid saturation was high.T he content of volatile acid in Yunyan85and Yunyan87 was low,but non-volatile and high fatty acids were high,and the difference between two varieties was not significant.

In order to investigate the reasons for the formation of aroma style of quality tobacco leaf and the accumulation of aroma components in flue-cured tobacco,the contents of aroma precursors,including plastid pigments(chlorophyll,lutein,β-carotene) and polyphenols(chlorogenic acid,rutin),and total sugar,reducing sugar,total nitrogen,protein,nicotine,potassium in the upper and middle leaves of flue-cured tobacco exposed to natural light with higher UV-B intensities were determined.The results showed that the synthesis of plastid pigment in upper leaves was suppressed,while that in middle leaves was promoted by intensified UV-B radiation;however,the synthesis of polyphenols was on the contrary.The contents of total sugar,reducing sugar,total nitrogen,protein and nicotine in upper leaves and total sugar and reducing sugar in middle leaves were decreased,while potassium content in upper leaves and the contents of total nitrogen,protein,nicotine and potassium in middle leaves were increased by intensified UV-B radiation.The main aroma precursors and chemical components in flue-cured tobacco were closely correlated to the intensity of UV-B,proper UV-B intensification would improve the aroma and quality of middle leaves of flue-cured tobacco.

To accurately identify the growing area of flue-cured tobacco,the contents of chemical components,including total sugar,reducing sugar,total nitrogen,nicotine,total chlorine and total potassium,in 402 cured tobacco samples collected from Yunnan,Henan,Anhui,Fujian,Guizhou and Jilin Provinces in 2010 were tested,and the samples were scanned by near infrared spectrometer.The near infrared spectra(NIR) pattern recognition models of growing area were developed by principal component analysis(PCA) and support vector machine(SVM) algorithms,and the growing areas of the samples were recognized.The results indicated that: 1) The prediction accuracy recognized by NIR-PCA-SVM models reached 97%,while that by chemical component-SVM and NIR-SVM models were lower.2) The NIR-PCA-SVM,and chemical component-SVM models all offered better recoginition for Yunnan tobacco samples.NIR-PCA-SVM model could be applied to pattern recognition of flue-cured tobacco samples of different origins.

Variance analysis was used to study the difference of 64 chemical indices of the flue-cured tobacco samples from China and other countries.The results showed that nicotine,total sugar,reducing sugar,total nitrogen,the difference between the total sugar and reducing sugar,the ratio of reducing sugar to nicotine,the ratio of total nitrogen to nicotine,K/(S+Cl),palmitic acid,linoleic acid plus oleic acid,total amount of higher fatty acids,damascenone,geranyl acetone and neutral volatile aroma components were significantly different or greatly significantly different among different flavor types or quality grades of flue-cured tobacco.The contents of benzaldehyde,hyacinthin,4-o-caffeoylquinic acid remarkedly affected the tobacco flavor type,and had no significant influence on quality grade;On the contrary,the contents of chlorine,sulphur,organic potassium,oxalic acid,malonic acid,phenethyl alcohol,solanone,the ratio of malic acid to citric acid,the ratio of calcium to malic acid and the ratio of total equivalent weight of nonvolatile organic acids to nicotine all remarkably effected the tobacco sensory quality grade,but had no significant influence on tobacco flavor type.

Routine chemical components,metal ions,organic acids,polyphenols,and neutral aroma constituents in both domestic and imported flue-cured tobacco leaves were analyzed with aroma types by simple correlation in order to provide experimental basis for reasonable evaluation and better use of tobacco leaves from different growing areas.Results showed that in total 53 chemical indexes,22 were highly significantly or significantly correlated with aroma types.Cluster analysis was then conducted with these 22 chemical indexes.Results showed that when T=12.4,tobacco leaves from 18 regions were divided into 2 groups:one was those from abroad and Shaanxi Ankang of China,the other was from regions except Ankang.When T=5.6,tobacco leaves from 18 regions were divided into 7 groups,which in turn were from Zimbabwe and Canada,from Brazil and Shaanxi Ankang,from Fujian,Hubei Enshi,Chongqing Qianjiang,and Jiangxi Gannan,from Liaoning,Sichuan,and Yunnan,from Guangxi,Hunan,and Guizhou,from Henan and Shandong,from Heilongjiang Mudanjiang and Jilin.

建立电感耦合等离子体质谱(ICP-MS)测定镉同位素比值的方法,应用同位素稀释电感耦合等离子体质谱(ID-ICP-MS )对环境和生物样品茶叶、湖沉积物和人发标准物质中的镉进行测定研究.对电感耦合等离子体质谱(ICP-MS )的工作条件和参数进行了最优化.讨论了多原子离子和同量异位素对镉同位素比值的影响,通过天然镉标准溶液对质量歧视进行了校正,并优化同位素稀释剂的加入量.将该方法应用于茶叶、人发和沉积物标准物质的测定.

The experiment aims to study combination of Cd and proteins in different tissues of rat fed with Cd isotope by SEC-UV-ICP-MS.In testicle,liver and kidney,Cd-MTs were found to be the binding product of Cd and MTs. This method is much more accurate,humanl than traditional method,and be able to distinguish the heavy metal from nature and artificiality.

应用两阶段聚类法对云南省大理州14个主栽烤烟品种C3F和C3L 2个等级的中部烟叶外观质量进行聚类分析,并应用多元方差分析对聚类效果进行了检验.结果表明,产地和品种对烤烟外观质量的影响较小,并将100 个烤烟样品外观质量分为3 个类型;明确了各类型烟叶外观质量的重要性状、变异特点和类型间的分类特性;其聚类分析结果与烤烟外观质量的实际表现相吻合,因而两阶段聚类分类结果客观、合理、准确、可靠.

Low concentration isotopic lead tracer (SRM982) was adopted, ICP-MS was used as a detection tool. By pot test, the chemical action of lead in tea under the condition of different pH and different modes of lead exposure was studied. Simulated rain water (C_(pb) = 0.5mg·l~(-1)) was used to pot soil and spray leaf to investigate the adsorption, distribution and migration of lead in two systerms: atmosphere-tea and soil-tea. The results are: 1. the reaction to lead pollution from atmosphere is more sensitive than that from soil; 2. the migration and distribution in tea of lead pollution from atmosphere and from soil is different, the former has the trend of conveying to bud while the latter focus mainly in root; 3. pH has an evidently effect on the migration of lead in tea, generally, low pH facilitates migration to upper parts. This method has the advantages that tea beared low polution, and the hazard to plant is less than traditional ways. In addition, lead from environment and from tracer can be separated.

Using flue-cured tobacco cv.K326 as material,the plant growth and leaf glandular trichomes development of flue-cured tobacco in the deficiency of nutrient elements during plant growing were studied.The results indicated that a deficiency of N,P,K,Mg not only negatively affected the growth of tobacco plant,but also had a significant effect on the growth and development of leaf glandular trichomes.N deficiency would decrease leaf area and stimulate the growth of various glandular trichomes,and the density of glandular trichome increased accordingly,while P,K,Mg deficiency would reduce the density of glandular trichome greatly besides leaf area reduction.Therefore,sufficient P,K,Mg nutrients application in the early growth stage of tobacco plant is particularly important for enhancing glandular trichome density and glandular secretion of tobacco leaves.

In order to investigate the relationship between main nutrient elements and aroma precursors of flue-cured tobacco,taking cv. K326 with liquid-based cultivation as material,changes in contents of major aroma precursors such as plastid pigments (chlorophyll,lutein,β-carotene) and polyphenols (chlorogenic acid,rutin) systematically in growing process of flue-cured tobacco under N,P,K,Mg deficiency condition were figured out. The results indicated that deficiency of major nutrient elements would seriously affect the main aroma precursors. N,K,P,Mg deficiency would extremely inhibit formation of plastid pigments and polyphenols anabolin,N deficiency affected carotenoid the most,P,Mg deficiency followed,K deficiency once again followed,and P deficiency affected polyphenols the most,Mg,K deficiency followed,N deficiency affected the least. Therefore,mainatining an adequate and reasonable supply of N,P,K,Mg in the latter period of production and having a further study on balanced fertilization are vital to improve the aroma and quality of flue-cured tobacco in China.

In order to investigate the feasibility of predicting nicotine,total sugar,reducing sugar,total nitrogen and potassium in reconstituted tobacco sheet with NIR transmission spectroscopy,the prediction models for the five components were established with partial least square(PLS) by using 100 representative samples of reconstituted tobacco sheet as the model calibration set and other 15 samples as the validation set.The predictive results and repeatability of the models were evaluated as well.The results showed that the correlation coefficients of NIR transmission spectrum prediction models for nicotine,total sugar,reducing sugar,total nitrogen and potassium were 0.9268,0.9575,0.9252,0.8024 and 0.9665,respectively.Aside from nicotine,the average relative predictive deviations of total sugar,reducing sugar and total nitrogen models were below 5%,and the average absolute predictive deviation of potassium was lower than 0.20,the predictive RSDs of these five components were below 5%.The predictive accuracy of NIR transmission models was slightly lower than that of NIR diffuse reflection spectrum models.NIR transmission spectrometry is suitable for rapid analysis of these five components in batches of reconstituted tobacco sheet samples.

We randomly selected 146 flue-cured tobacco samples from 9 provinces in China and 40 abroad to determine the alkaloid contents of flue-cured tobacco leaves by gas chromatography,and its variation pattern,geographical distribution and correlation were analyzed.The results showed that for domestic samples,the alkaloid content variation were wider than that abroad,the contents of total alkaloid and nicotine were high,while the nornicotine,the myosmine,the anabasine and the anatabine alkaloids were low,the alkaloids were ranked from high to low as nicotine,anatabine,nornicotine,anabasine and myosmine.There was a positive correlation among nicotine,nornicotine,myosmine,anabasine and anatabine.There exsisted highly significant difference in alkaloid contents among different leaf positions,which ranked from high to low as B2F,C3F and X2F.In terms of nicotine conversion rates,grades were ranked from high to low as B2F,C3F and X2F.There was highly significant difference in nicotine content and nicotine conversion rates among tobacco leaves from nine provinces.The total alkaloid content were ranked from high to low as Guangxi,Fujian,Hunan,Shandong,Guizhou,Liaoning,Yunnan,Henan and Sichuan,while the Anatabine,nornicotine,anabasine and myosmine;nicotine conversion rates were ranked as Sichuan,Henan,Liaoning,Yunnan,Guizhou,Hunan,Shandong,Fujian,Guangxi.There was a significant correlation between alkaloid content and sensory quality,and nicotine had largest influence on sensory quality,while there were significant negative correlations between nicotine and aroma,after taste,offensive odor,irritancy.But nicotine conversion rates had no significant correlation with sensory quality.There was a significant negative correlation between alkaloid and composite quality.There was no significant correlation between nicotine conversation and composite quality.

In order to test the applicability of support vector regression (SVR) in near-infrared (NIR) spectral analysis of tobacco,NIR calibration model for starch in tobacco were developed by processing NIR spectra and chemically determined starch content data of 187 tobacco samples with SVR,partial least square regression (PLS),multiplicative linear regression (MLR) and error back propagation artificial neural network (BP-ANN). The obtained model was tested through internal validation and external validation with leave-one-out cross validation (LOOCV) and independent sample set. The results showed that the accuracy of SVR model was slightly higher than that of BP-ANN,PLS and MLR models,it implied that SVR algorithm could be applied to NIR analysis of starch in tobacco.

Effect of soil moisture on aroma and chemical components of flue-cured tobacco during various mature stages was studied. Tobacco plants were grown in pots and relative soil moistures were controlled at 40% or 80% of every treatment at different stages i.e. defining length stage,immature stage,and mature stage. Results indicated that content of cembranoids,carotenoids,Maillard chemical substances,and aromatic fragrance substances of flue-cured tobacco increased through short-time drought after topping,while continuous drought was disadvantageous to the formation of those latent fragrant substances. Any short-time drought was benefit to the formation of latent fragrant substances,while continuous drought was unfavorable during mature stage. Content of water-soluble sugar and reductive sugar in green leaves increased with disconnected drought after topping,so did the content of total nitrogen and nicotine. Potassium content increased a little at defining length,mature,and whole mature stage drought.

A rapid method was developed for measurement of pH value based on the combination of near infrared(NIR) diffuse reflection spectroscopic and chemometrics methods.The spectral data of tobacco were collected by Thermo Antaris Near-IR Analyzer,and analyzed by first derivative,second derivative and Savitzky-Golay filter smoothing.The pH prediction models were established with prediction 572 calibration samples by partial least squares(PLS) method,and the distribution of principal component scores and pH values of 81 validation samples was investigated.Results indicated that the 81 validation samples have broad and fine distribution.The pH values of validation samples and fine average absolute deviation(AAD) were tested by first and second derivative prediction models of master instrument.The AAD of predicted values and measurement values were 0.057 and 0.065,respectively.t-Test results indicated that no significant difference was found between prediction value and test value.In the meantime,the calibration transport effect of pH first derivative and second derivative prediction models of master instrument among 7 NIR devices with the same types was also investigated,respectively.The AAD were between 0.049 and 0.070,and all devices were passed F-test.Therefore,the prediction models of master instrument could be applied to pH fast test,and be successfully transported to other instruments of the same type.

The distributions of lead and cadmium in rats were studied using stable isotope tracer technique.The rats were fed with enriched stable isotope 206Pb and 112Cd,then the liver,kidney,testicle and heart were eviscerated.After chemical treatment,the contents of lead and cadmium and their isotope ratios in each viscera were determined by ICP-MS.Experimental results showed that lead and cadmium accumulated mostly in liver and kidney,next in testicle and heart,and least in brain.The utilization rates of cadmium and lead isotopes in liver were 0.048 8% and 0.010 1%,respectively,and in kidney 0.015 4% and 0.007 8%,respectively.Compared with the traditional methods,the present method can differentiate the origins of lead and cadmium.

An on line vapour generation ICP-MS method for the determination of iodine was established.In the paper,depending on the deoxidization of the I-and the means of oxidization,sensitivity was raised due to improving transfer efficiency by using the technique which the I-was oxidized to I that was volatile before being detected.Detection limit of the method was 0.22 μg/L,Recoveries obtained were in range of 87.4%～97.75% and RSD(n=11) was less than 3%.In the study,I5+ was deoxidized to I-in advance,and then I-was oxidized to I before being detected.

The development of Chinese style cigarettes depends on the stable supply of leaf tobacco materials with high quality and good characteristics. Necessity to construct safeguarding system for those materials was examined with emphasis on particular the importance of substitution of import. Detailed suggestions were proposed.