Study On Reducing The Main Hazardous Compounds In Cigarette

Smoking and health is always one of the focus topics in the world. Reducing tar and removing harmful components in cigarette smoke is the most important task. In this thesis, new techniques, new methods and new materials as well as their applications to tobacco and cigarettes to remove harmful components were introduced. With systemic studies on the main harmful components in tobacco and cigarette smoke, the methods of determination of polycyclic aromatic hydrocarbons (PAHs), tobacco specific N-Nitrosoamines (TSNAs), phenols and heavy metals in tobacco and mainstream smoke (MS) and sidestream smoke (SS) were established. Furtherly, the method of cell toxicology for the safety of cigarette smoke and related safety-evaluated system was set up and improved here. On the other hand, with a lot of tests, the additives which could selectively reduce harmful components were prepared. Two application ways (addition and loading) of catalytic additives to cigarettes were compared and evaluated, and cigarette smoke analysis by smoking machine and sense evaluation of the cigarettes were taken. The results demonstrated that they can remarkably reduce the harmful components of smoke. Sense evaluation showed that these additives could keep the original style of cigarettes, and also improved the taste of smoke. Furthermore, the additives were applied to cigarette products, and the results of analysis and sense evaluation were satisfied. The details of this thesis were divided into several parts as follows.(1) A new qualitative and quantitative analysis method for simultaneously determining 16 kinds of polycyclic aromatic hydrocarbons (PAHs) was first established. These PAHs including benzopyrene [B(a)P] in MS could be analyzed with the method of GC/MS, after the PAHs in MS purified by column chromatography and enriched together. PAHs in about 100 kinds of cigarette smoke which contain various content of tar were determined with this method. The results demonstrated that this method was rapid, accurate, sensitive and stable, and the recoveries of the main PAHs was above 95%. So it is an ideal way for the analysis of PAHs in cigarette smoke.After analyzing and studying the PAHs analytical data in above 100 kinds ofbrand cigarettes' MS and SS with different tar content, the results showed that the total content of PAHs in SS was always higher than that in MS, and the PAHs and the tar in MS had a good relativity.The effect of filter's permeability on PAHs in MS was investigated and discussed. The results demonstrated that the content of PAHs in MS was negatively related with the filter permeability using electrostatic or laser stioletto mode, but positively with the total particle materials (TPM).(2) A method with good repeatability, high recoveries and accuracy for qualitative and quantitative analysis of (TSNAs) was established. By using this method, TSNAs in above 100 kinds of brand cigarettes' MS and SS with different tar content were determined.NO3", NO2", nicotine and TSNAs in different grade flavor tobacco lamina and stem were examined. The analytical data showed that the contents of NO3", NO2 , nicotine and TSNAs gradually increased with the increase of the tobacco leaves grade from the first to the fourth grade, and so did these in the stem, which indirectly indicated that the content of TSNAs had a positive correlation with these of NO3", NO2 and nicotine in tobacco lamina and stem. This gives a clue to control TSNAs content in the procedure of tobacco leaves treated with Chemical, Biological or Physical techniques after harvest.The effect of filter's permeability on TSNAs in MS was studied and discussed. The results showed that the content of TSNAs in MS was negatively related with the filter permeability using electrostatic or laser stioletto mode.(3) A method of online solid-phase extraction enrichment and high performance liquid chromatography was established, which could be used to determine aromatic amines, such as aniline, 2, 4-dimethylaniline, 1-naphthylamine, 2-naphthylamine, 4-aminobiphenyl in MS. This method had good repeatability, high recoveries and considerable sensitivity, and could be used for the determination of several kinds of aromatic amines which only contained several nanograms (ng).(4) A method for determining 7 kinds of main phenols by high performance liquid chromatography (HPLC) was established. The recoveries of these 7 kinds of main phenols ranged from 95% to 97%, and their RSD was in the range from 2.0% to3.6%. The result was satisfied. In addition, the content of phenols of many brand cigarettes was compared and analyzed.(5) The new methods for the determination of several kinds of heavy metals in TPM were systemically studied. A method for determining these elements in TPM by using online solid-phase extraction enrichment and inverse liquid chromatography was established, and analyzed 6 kinds of heavy metals of tobacco or tobacco additives such as nickel, cuprum, stannum, plumbum, cadmium and hydrargyrum. The colored compounds formed by trace quantity heavy metal ions and porphyrin were separated with HPLC, and then determined by photodiode arry detector. This way could overcome the shortcoming of bad selectivity of photometry, and could determined several elements simultaneously. So it had good repeatability, high recoveries and considerable sensitivity, and it was satisfied to determined 6 kinds of trace quantity heavy metal elements mentioned above in tobacco additives.(6) Nanoparticles and additives for the reduction of the harmful components in MS were studied and prepared. The functional additives to selectively reduce harmful components in smoke were selected and prepared by many tests. The effect of these additives were compared and evaluated after added or loaded to tobacco by smoke analysis and sense evaluation. Two efficient additives, 1# and RC, were selected. Additive 1# was a catalyst and RC was an additive to reduce harmful components in smoke. The analytical results of the cigarettes added these two additives demonstrated that they can remarkably reduce the harmful components of smoke. For Additive 1#, the reduction ratios of TPM, TSNAs, B(a)P and carbon monoxide(CO) were 33.3%, 28.6%, 14.3% and 27.9%, respectively;for RC, these of TPM, NNN, NNK, NAT+NAB, total TSNAs, nitridoxides and B(a)P were 15.0%, 22.75%,17.60% 3.86%, 11.13%, 19.05% and 15.0%, respectively, and CO was reduced by 15% to 20%. Sense evaluation showed the two additives can keep the cigarette original style, and also improve the taste of smoke.The smoke of the cigarettes added with the additive RC was carried out a series of tests for cell toxicology (MTT method). The result showed that these cigarettes led to a significant higher survival ratio compared with control group, which indicated this additive could protect the cells from poisons in smoke. The result ofcell oxidation stress test showed that the O2" amount induced to yield by the smoke of the cigarettes added this additive is less than that of control cigarettes, which indicated this additive could depress the oxidation to cells to some extent. From these tests described above, a conclusion was drawn that these additives could reduce the toxicity and damage of cells induced by the smoke, and could make cigarette safer upon compared with control sample.(7) Assembling application of tar- and harm-reducing techniques and development of low tar and low CO cigarette products. It was found in investigation that the application of a single technique could reduce the tar and harm without high performance and simultaneously keep a good smoke taste of cigarettes. Although a single technique could reduce some parts of harmful constituents to some extent in MS, it could lead a decrease of the smoke flavor and the change of smoke style. So a single technique was not the most effective way to improve the taste of a cigarette and reduce tar and harmful constituents of smoke. With the assembling of several techniques mentioned above, a cigarette product with low tar and low harm (tarlO.lmg, CO 9.0mg, and nicotine l.Omg per cigarette) was successfully developed.(8) A modified apparatus of pyrolysis was invented to evaluate the behavior of combustion of cigarette under the existence of oxygen. Pyrolysis of flue-cured tobacco lamina and stem was conducted in the air at different temperatures (300°C -. 600°C ^ 900°C) and their pyrolysate was analyzed by GC/MS. The results indicated that the pyrolysates of amino acids, non-volatile organic acids and their salts, sugars, tobacco lamina and stems the kinds of pyrolysate of tobacco lamina and stem increased with the increase of the pyrolysis temperature, at the same time a lot of PAHs were produced. And at the same temperature, the kinds of the PAHs induced by the pyrolysis of tobacco lamina were more than those of tobacco stem.