In order to clarify the main harmful components in mainstream smoke of flue-cured tobacco leaves from different growing areas in China,we selected 266 flue-cured tobacco samples from 17 flue-cured tobacco-producing provinces (municipalities) and 36 representative areas,and studied the differences of the main harmful components in mainstream smoke of flue-cured tobacco leaves between different areas and leaf positions,and variations of the same variety between different growing areas,leaf positions and years.The results showed that there were some variations of the main harmful components in mainstream smoke of flue-cured tobacco in China,of which,the coefficients of variation of NNK,ammonia and phenol were larger,those of benzopyrene and hydrogen cyanide were medium,and those of tar and crotonaldehyde were smaller.The differences in contents of tar,crotonaldehyde,NNK,ammonia,hydrogen cyanide and phenol in mainstream smoke of flue-cured tobacco leaves between different growing areas were significant,while the differences in carbon monoxide and benzopyrene were not significant.The differences in contents of tar,phenol,croton aldehyde,ammonia and NNK of mainstream smoke of flue-cured tobacco leaves between different leaf positions were significant,while the differences in carbon monoxide,benzopyrene and hydrogen cyanide were not significant.The variations of contents of hydrogen cyanide and NNK of flue-cured tobacco leaves between different growing areas were the highest,and the variation of content of phenol between different leaf positions was the highest.The variation of benzopyrene content between different leaf positions and between growing areas were higher than those between different years,and the variations of the contents of tar,carbon monoxide and crotonaldehyde between different leaf positions,growing areas and years were smaller.

To investigate the effects of biochar application on tobacco field, pot experiments were conducted to study the impacts of straw biochar at different levels on tobacco growth, soil organic carbon and enzyme activities. The results showed that the growth of tobacco was promoted by biochar application in the soil at moderate levels (0.2%-1.0%). Tobacco height, tobacco leaf area, and the biomass of stem and leaves were all increased with moderate levels but inhibited by the high level (5.0%) of biochar application. Different from the aboveground organs, the growth of tobacco roots and the root/shoot ratio were both promoted with the tested levels of biochar application, with the 5.0% level of biochar treatment having the highest root biomass and root/shoot ratio. Moreover, the contents of soil organic carbon and active organic carbon both increased with the increase of biochar application, reaching the highest values in the 5.0% biochar treatment. The increase of active organic carbon was however less than that of total organic carbon. The soil urease, invertase and acid phosphatase activities all increased in different extent with the increase of biochar application, but the catalase activities were decreased or not changed. In summary, the effects of straw biochar application on tobacco growth and soil biological activities are very important, but the interaction between biochar and soil is a long-term process in tobacco field. Long-term experimental studies should be conducted to test the positive and negative effects of biochar application on tobacco growth and development and its related mechanisms.

In order to identify the soil factors of shandong tobacco areas on the effect of oil in flue-cured tobacco leaves,the relationship between land conditions(landforms,soil types,soil textures,elevations and soil nutrient conditions) of four ecotypes in Shandong and oil in different parts of flue-cured tobacco leaves was analyzed.The result showed that different landforms and soil textures played important roles in the oil in middle leaves and upper leaves,especially for the middle leaves.The upper and middle leaves from hilly areas was significantly better than those from mountain areas.The oil in tobacco leaves from argillaceous soil performed worse on the whole.Oil in middle leaves was significant lower than those from sandy loam.There was no significant difference between neutral loam and sandy loam soil.Soil types,elevations and soil nutrient conditions had no significant effect on oil in different parts of tobacco leaves.There was no significant difference about oil in tobacco leaves between the four ecotypes.

18 of free amino acids in tobacco were simultaneously determined by high performance anion-exchange chromatography with integrated pulsed amperometric detection method.The results showed that the recoveries for 18 amino acids were in the range of 80%-115%,the detection limits for 18 amino acids were 0.03-0.75 μg/mL and the calibration graphs of peak area for the analyses were linear over about three orders of magnitude with a correlation coefficient of 0.9900-0.9992.The method was applied to determine 18 free amino acids in tobacco with satisfactory results.The method was employed to determine 18 free amino acids in flue-cured tobacco,burley tobacco and oriental tobacco.The method was also employed to determine successfully 18 free amino acids of different brands of domestic cigarettes and overseas cigarettes.

In order to investigate the correlations between the delivery of ammonia in mainstream cigarette smoke and the contents of nitrite,nitrate and ammonia in tobacco leaf,the delivery of ammonia in mainstream smoke and the contents of nitrite,nitrate and ammonia in 18 samples of flue-cured tobacco leaves from different stalk positions from Shandong,Yunnan and Fujian in 2007 and 2008 and 3 imported leaf samples were determined by ion chromatography.The simple correlation analysis was conducted and the significance of correlation was tested.The results showed that the delivery of ammonia in mainstream cigarette smoke significantly positively correlated with the content of nitrite in tobacco leaves,while its correlations with nitrate and ammonia were not significant.

Comparative study the yield of tar,nicotine,water,carbon monoxide,ammonia and phenol in mainstream smoke of different cigarettes under two smoking methods,ISO method and Health Canada method.The yield of tar,nicotine,water,carbon monoxide,ammonia and phenol in mainstream smoke under Health Canada method is the higher than them under ISO method.With the increase of filter ventilation rate,the increasing amplitude of the tar,nicotine,water,carbon monoxide,ammonia and phenol in the mainstream smoke is increasing under Health Canada method.It is found that the rates of increase of water in mainstream smoke under Health Canada method are greater than the other five components.

To explore effective protective agents of stored tobacco,the toxicity of seven kinds of pesticides: Deltamethrin(98.5%),Cyhalothrin(97.1%),Betacyfluthrin(27%),Emamectin benzoate(66.67%),Fenvalerate(65.9%),Avermectins(8.08%),Pririmiphos-methyl(90%) against cigarette beetle(Lasioderma serricorne) were tested.The results showed that: the toxicity of Cyhalothrin(97.1%) to the larvae of cigarette beetle was the highest,the LD50 of Cyhalothrin was 2.91061 mg/L.Followed by Deltamethrin(98.5%),Betacyfluthrin(27%),Pririmiphos-methyl(90%),Fenvalerate(65.9%).The lowest toxicity to the larvae of cigarette beetle was Emamectin benzoate(66.67%).The highest toxicity to the adults of cigarette beetle was Pririmiphos-methyl(90%) among the four kinds of pesticides tested.

The amino acid analytical research is important in the analytical chemistry domain.This paper reviews a variety of research and development for amino acid analysis,introduces the main amino acid analysis methods of paper chromatography and thin-layer chromatography,gas chromatography,high-performance liquid chromatography,high-performance anion-exchange chromatography with integrated pulsed amperometric detection method,capillary electrophoresis and looks forward to the development trends for amino acids analysis.It provides reference for choosing the most appropriate method for the amino acid analysis.

In order to remove tobacco specific nitrosamines(TSNA),this study tried SBA-15 with specific 3D net-linked morphology as adsorbent to reduce particles and nitrosamines level of tobacco smoke.The results showed that this 3D net-linked SBA-15 could efficiently reduce the content of total particles and tar,and eliminated 40% of TSNA from mainstream smoke when it was used as filter additive of cigarette,and the content of NNN and NNK decreased dramatically as well.

In order to obtain a fast and available process to control the quality of flavored cut tobacco,the sensor array fingerprint technology of electronic nose (E-nose) was applied in identifying of flavored cut tobacco according to volatile compounds.The data acquired by electronic nose were analyzed by the principal component analysis (PCA) in order to reduce data dimension and optimize feature vectors.The results indicated that electronic nose could discriminate cut tobacco from flavored cut tobacco and evaluate the uniformity of flavored cut tobacco effectively.The data analyzed by Statistical Quality Control (SQC) could evaluate the quality of flavored cut tobacco effectively according to the volatile components in cut tobacco during the production process.The shelf life of the electronic nose analyzed the effect of the storage time on change of volatile components of flavored cut tobacco.The results indicated that the volatile components of flavored cut tobacco decreased with the increase of the storage time;however,the uniformity of flavored cut tobacco was better with the increase of the storage time.According to the two factors,the best storage time for flavored cut tobacco was identified.

Two prediction models were developed to predict occurrence tendency of alate aphids migration.The peak period of alate aphids migration was divided to 4 levels in Shandong tobacco growing region.Based on data in the past 10 years,stepwise regression and BP neural network were employed to establish prediction models of alate aphids migration peak period,respectively.The prediction accuracy of the two methods reached 95.00% and 97.67%,and back prediction accuracy reached 96.65% and 98.74%,respectively.The alate aphids migration peak period can be predicted one month in advance through the established prediction model,which can serve as a middle-term prediction model applied in the control of tobacco aphid and aphid-borned tobacco virus diseases.

Cluster analysis was employed on the chemical compositions of 97 flue-cured tobacco leaf samples (C3F) from seven counties of Baise, Guangxi to enhance tobacco leaf utilization, tobacco production technology and related cultivation management in different regions. Results showed that three regions could be divided in Baise. The first included Longlin, Xilin and Tianlin, and the second included Leye, Lingyun and several towns of Debao, such as Xingwang, Wuping, and Jingde etc. The third included most parts of Jingxi and some towns of Debao, such as: Puxu, Duan, Lutong, Dongling, Najia, etc. The flue-cured tobacco leaves in the three parts exhibited evident quality characteristics including appearance quality, chemical composition and sensory quality.

By using the Wrapper feature extraction algorithm in data mining methods,the key indicators were extracted,which significantly impacted the aroma quality of flue-cured tobacco.The method was compared with the simple correlation coefficient method.The results showed that there were 20 kinds of aroma components which mainly impacted the aroma type,such as geranylaceione,pentanoic acid,total acid,megastigmatrienone,solanone,while 25 types of aroma components which mainly impacted the volume of aroma,such as geranylacetone,2-acetyl pyrrole,tetramethylpyrazine,benzaldehyde,solanone,isovaleric acid,β-dama-scenone.There were 18 types of aroma compontents which mainly impacted the quality of aroma,such as megastigmatrienone,isovaleric acid,solanone,total neutral,neophytadiene,geranylacetone,farnesylacetone,3-methylpentanoic acid,tetramethylpyrazine,β-damascenone,pyridine.The performance of the model was improved greatly by using the extracted features,which were built between aroma components and aroma quality.Compared with piecewise linear regression model,the RBF neural network model has better accuracy in prediction.

In order to provide on site chemical analysis data of tobacco leaves to quality agent at purchase, NIRS method was used to determine the chemical component of tobacco leaves. The ten points of handed tobacco leaf surface was combined into one mean spectrum, which was correlated with the determination results of chemical components by flow analyzer, and the mathematical models were established with average correlation coefficients over 0.9. The designed NIRS model is reliable and practical for chemical components determination of handed tobacco leaves.

The field trial of residue level and degradation dynamics of Metalaxyl-M in tobacco and soil were carried out in Shandong and Hunan during 2005-2006.The results showed that the degradation speed of meta-laxyl-M in tobacco leaves was faster than in soil,its half-life periods were 1.2 to 1.5 days in tobacco leaves and 6.4 to 2.8 days in soil.By applying 3 to 4 times with the guide dosage,the pesticide residue in leaf was less than 2 mg/kg in 14 days after the last application.It was suggested to end the application of Metalaxyl-M at least 21 days ahead of tobacco harvest for safety's sake.