Effect of exogenous softwood on thermal decomposition of reconstituted tobacco sheet

In recent years, reconstituted tobacco sheet (RTS) has played an increasingly vital role in reducing tumorigenicity for tobacco industry. In this paper, two plant fibers of tobacco pulp (TP) and softwood pulp (SP) were added independently as strengthening agents during the paper-making process to manufacture RTS (TP-RTS and SP-RTS). The effects of exogenous SP on the CO yield in cigarette mainstream smoke, thermal behavior, and gaseous products evolution properties of RTS were evaluated and compared with TP. The CO yield in cigarette mainstream smoke was studied using smoking machine and CO analyzer. The thermal behavior of two RTS was studied by thermogravimetric (TG) analysis, and the gaseous products were investigated by Fourier transform infrared spectrometer (FTIR). CO yield in cigarette mainstream smoke results demonstrated that SP-RTS (3.16 mg per puff) presented higher CO yield per puff than TP-RTS (2.83 mg per puff). TG analysis results demonstrated that the maximum mass loss rate of SP-RTS (23.3 % min^?1) was drastically higher than that of TP-RTS (15.8 % min^?1). FTIR results illustrated that SP-RTS presented stronger absorbance intensity associated with generation of more gaseous products than TP-RTS. In the thermal decomposition stage, the maximum mass loss rate of SP (78.6 % min^?1) was clearly higher than that of TP (38.4 % min^?1), and SP increased the generation of gaseous products compared to TP.     

The generation of carbon monoxide and carbonyl compounds in reconstituted tobacco sheet

In recent years, reconstituted tobacco sheet (RTs) has played an increasingly significant role in tobacco industry. The yields of CO and carbonyl compounds (formaldehyde, acetaldehyde, acetone, acrolein, propanal, butenal, 2-butanone, and butyraldehyde) in cigarette mainstream smoke of RTs and their formation mechanisms were investigated in this paper. Self-made RTs (SRTs) was studied and compared with foreign Mauduit RTs (MRTs) and three commercial tobacco leaves on routine chemical constituents, thermal behavior, and subsequent gaseous products evolution. The cigarette smoking results illustrated that the yields of CO (2.9 mg per puff) and carbonyl compounds (about 208 μg per puff) in mainstream smoke of SRTs and MRTs were at the same level, and obviously higher than those of three commercial tobacco leaves. The routine chemical constituent results demonstrated that bright tobacco and oriental tobacco contained particularly higher contents of reducing sugar and total sugar than RTs, while burley tobacco had a high content of nitrogen compounds. The thermal behavior results showed that SRTs (11.6 % min^?1) and MRTs (14.5 % min^?1) presented higher maximum mass-loss rate than bright tobacco (7.8 % min^?1), burley tobacco (7.1 % min^?1), and oriental tobacco (6.8 % min^?1). The thermal decomposition of saccharides and combustion of residual char played the most important roles in mass-loss and gaseous products formation. The decomposition of saccharides and incomplete combustion of carbonized residual char primarily contributed to the formation of CO, while carbonyl compounds evolution was mainly attributed to the decomposition of saccharides alone.     

Physical properties and thermal behavior of reconstituted tobacco sheet with precipitated calcium carbonate added in the coating process

Addition of precipitated calcium carbonate (PCC) to cellulosic products can reduce production costs and modify their physical properties. This study investigated the effects of adding PCC on the properties of reconstituted tobacco sheet (RTS), a cellulosic product. Scanning electron microscopy (SEM) analysis showed that adding PCC to the coating could modify the surface microstructure of RTS. With increasing PCC addition, the strength and tar release per cigarette of RTS decreased. However, the filling capacity, bulk, and CO release content in the mainstream smoke reached optimal values when the proportion of PCC in the coating was 8%. Thermogravimetry (TG) and differential thermogravimetry (DTG) analysis indicated that the main thermal pyrolysis stage occurred in the range of 200–400 °C, similar to cellulosic components. The Coats–Redfern equation was used to analyze the thermal pyrolysis mechanism. The fitting results showed that, in the range of 200–280 °C, the best fit model for RTS with 4 or 8% PCC was diffusion-controlled reaction (D1) with fitting correlation coefficient (r ²) of 0.9630 and 0.9576, respectively. Meanwhile, in the range of 280–400 °C, the most reliable fitting model for RTS with 4% PCC was chemical reaction (F2) with r ² = 0.9681. One reaction model could not describe the thermal pyrolysis of RTS with 12% PCC in the main decomposition stage. The thermal kinetic parameters suggested that addition of PCC to RTS coatings could modify the thermal pyrolysis mechanism, but did not change the peak temperatures in the main thermal decomposition stage. This study demonstrates that addition of PCC to RTS coating is a promising method to improve its quality.     

Analysis of Vinyl Chloride in Vapor Phase of Mainstream Cigarette Smoke by GC–MS Under ISO and Health Canada Intensive Machine Smoking Regimens

Vinyl chloride (VC) in the vapor phase of mainstream cigarette smoke was determined under both International Organization for Standardization (ISO) and Health Canada intensive (HCI) machine smoking regimens, which was suspected to be carcinogenic compound. VC was collected by passing the mainstream cigarette smoke through a Cambridge Filter Pad (CFP) into cryogenic traps containing methanol. The impinger solutions were fortified with VC-d ₃ and analyzed by GC–MS. Limits of detection for vinyl chloride was 0.9 ng mL^?1 with the recovery in the range of 93.2–98.4 %. Moreover, the intra-day and inter-day precision was 7.39 and 9.77 %, respectively. Under HCI machine smoking regimen, the vinyl chloride yields in vapor phase of mainstream cigarette smoke were much higher and the average increase was greater than 100 % compared with those under ISO smoking condition.     

不同材料滤嘴对卷烟主流烟气中挥发性羰基化合物截滤性能的研究

吸烟是引起肺癌及相关疾病的主要原因[1]。挥发性羰基化合物(如甲醛、乙醛、丙醛、丙酮、丙烯醛、巴豆醛、丁酮和丁醛)是卷烟主流烟气中含量较高的一类有害成分,含量从几十到几百微克不等[2-3]。这些挥发性羰基化合物特别是甲醛、丙烯醛及巴豆醛具有纤毛毒性,与氰化氢和氨一起,     

多聚磷酸铵对再造烟叶热解行为与CO释放量的影响

应用热重分析研究多聚磷酸铵（APP）对再造烟叶热解行为的影响．热分析结果表明,APP降低再造烟叶热降解速率及其热释放量、促进了碳的形成,对再造烟叶的热降解起一定的阻碍作用．此外APP显著影响再造烟叶的热解过程中的气相产物,再造烟叶的CO单支释放量与单口释放量随着APP含量的增加快速下降．慢速热解与闪解实验结果显示升温速率是APP降低C0释放的关键因素。     

A rapid and selective method for simultaneous determination of six toxic phenolic compounds in mainstream cigarette smoke using single-drop microextraction followed by liquid chromatography–tandem mass spectrometry

Cigarette smoke contains several toxic phenolic compounds, measurements of which are essential from a public health standpoint. This article describes a simple and selective analytical method for quantitative determination of six toxic phenolic compounds (phenol, catechol, resorcinol, hydroquinone, o-cresol, and p-cresol) from mainstream cigarette smoke using single-drop microextraction in combination with liquid chromatography–tandem mass spectrometry. Single-drop microextraction was applied prior to analysis by liquid chromatography–tandem mass spectrometry for the extraction and preconcentration of target phenolic compounds from raw cigarette smoke extract. The effects of the extraction solvent, sampling time, solution pH, salt addition, sample agitation rate, and temperature on the extraction efficiency were examined and optimized. The identification of each analyte was established by chromatographic retention times, analyte-specific fragmentation patterns, and relative peak area ratios of two product/precursor ion pairs. Analytical parameters such as the detection limit, relative recovery, reproducibility, linearity, and enrichment factor were evaluated under the optimized experimental conditions. 1-Decanol was selected as the extraction solvent and the limits of detection were found to be in the range of 0.05-0.3 ng mL^-1 using an extraction time of 12 min. Gradient chromatographic conditions were optimized for the separation of the six phenolic compounds in a run time of 10 min including reequilibration of the column. The present method for determination of phenolic compounds from mainstream cigarette smoke is simple and specific and shows good reproducibility, with relative standard deviations less than 10 % for all targeted phenolics.

快速分离柱高效液相色谱法测定卷烟主流烟气中的主要羰基化合物

选择2,4-二硝基苯肼(DNPH)为羰基化合物的衍生化试剂,建立了快速分离柱高效液相色谱测定卷烟主流烟气中8种羰基化合物的方法。采用经2,4-二硝基苯肼酸性溶液处理过的剑桥滤片捕集烟气,再用含2%（体积分数）吡啶的乙腈溶液进行萃取,以ZORBAX Stable Bound色谱柱(50 mm×4.6 mm,1.8 μm)进行快速分离,最后由二极管阵列检测器于365 nm下进行检测。该方法的回收率为89.1%～99.2%,相对标准偏差（RSD)在6.0%以下。该方法分析时间短,流动相消耗少,且操作简便、重复性好、回收率高。     

GC–MS Analysis of Hydrogen Sulfide,Carbonyl Sulfide,Methanethiol, Carbon Disulfide,Methyl Thiocyanate and Methyl Disulfide in Mainstream Vapor Phase Cigarette Smoke

A method is described for the simultaneous analysis of hydrogen sulfide, carbonyl sulfide, methanethiol, carbon disulfide, methyl thiocyanate and methyl disulfide in mainstream vapor phase (MVP) cigarette smoke by gas chromatography–mass spectrometry. The fresh MVP smoke was collected in a gas bag, followed by injection of a 50 μL gas sample into the GC inlet via an automatic six-port valve. The separation was on a CP-PoraPLOT Q column and MS was operated in SIM mode. It was found that while carbonyl sulfide and carbon disulfide are very stable in the gas bag, hydrogen sulfide, methanethiol, methyl disulfide and methyl thiocyanate are extremely reactive and their levels increase or decrease drastically with the storage time in the gas bag. These results suggest that there is an absolute need to analyze the smoke sample as quickly as possible. Maintaining a precise time after the smoke collection is a key factor in order to obtain reproducible results. In this study, all the samples are injected within 2 min after MVP smoke was collected in the bag. Under smoke conditions of 60 mL puff of 2 s duration every 30 s, 12 brands of commercial cigarettes and Kentucky Reference 2R4F cigarettes were analyzed. Average values of three replicates of the 2R4F cigarettes were 31.6 μg cigt^?1 hydrogen sulfide, 40.7 μg cigt^?1 carbonyl sulfide, 25.6 μg cigt^?1 methanethiol, 2.2 μg cigt^?1 carbon disulfide, 23.7 μg cigt^?1 methyl thiocyanate and 17.6 μg cigt^?1 methyl disulfide. All other types of analyzed cigarettes show a similar quantitative distribution for these analytes.     

Molecularly imprinted polymers on a silica surface for the adsorption of tobacco‐specific nitrosamines in mainstream cigarette smoke

Tobacco‐specific nitrosamines are one of the most important groups of carcinogens in tobacco products. Using adsorbents as filter additives is an effective way to reduce tobacco‐specific nitrosamines in cigarette smoke. Molecularly imprinted polymers (MIPs) using nicotinamide as template were grafted on the silica gel surface to obtain MIP@SiO₂ and employed as filter additives to absorb tobacco‐specific nitrosamines in mainstream cigarette smoke. Four milligrams of MIP@SiO₂ per cigarette was added to the interface between filter and tobacco rod to prepare a binary filter system. The mainstream smoke was collected on an industry‐standard Cambridge filter pad and extracted with ammonium acetate aqueous solution before analysis. Compared to the cigarette smoke of the control group, the levels of tobacco‐specific nitrosamines with silica gel and with MIP@SiO₂ were both reduced, and the adsorption rates of N‐nitrosonornicotine, N‐nitrosoanabasine, N‐nitrosoanatabine, and 4‐(methylnitrosamino)‐1‐(3‐pyridine)‐1‐butanone with silica gel and with MIP@SiO₂ were 20.76, 15.32, 18.79, and 18.01%, and 41.33, 34.04, 37.86, and 35.53%, respectively. Furthermore the content of total particle materials in cigarette smoke with silica gel was decreased evidently but showed no observable change with MIP@SiO₂. It indicated MIP@SiO₂ could selectively reduce tobacco‐specific nitrosamines in the mainstream cigarette smoke with no change to the cigarette flavor.     

卷烟主流烟气中挥发性羰基化合物分析研究进展

挥发性羰基化合物是卷烟烟气中主要有害成分之一,在抽吸卷烟的过程中会不同程度地刺激人体的感觉器官和呼吸系统,长期吸入会对人体造成严重的危害。文章介绍了卷烟主流烟气中挥发性羰基化合物的形成机制和前提物,综述了羰基化合物的捕集方法、衍生化和检测手段。     

Effects of melamine phosphate on the thermal decomposition and combustion behavior of reconstituted tobacco sheet

In this paper, first the MP-modified reconstituted tobacco sheet (RTS) was prepared by a paper-making process. Thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) had been used to investigate the influences of melamine phosphate (MP) on the thermal decomposition and the formation of evolved volatile products of RTS. TG-FTIR results illustrated that the incorporation of MP into RTS could retard the thermal decomposition of the major components of RTS and meanwhile lead to the formation of more thermally stable char. Moreover, the main gases released during the pyrolysis of RTS and MP-modified RTS were H₂O, CO₂, CO, NH₃, carbonyl compounds, alcohols, phenols, alkanes, and alkenes. The presence of MP changed the formation of evolved volatile products of RTS obviously. The effects of MP on the combustion behavior of RTS were studied by micro-scale combustion calorimetry and cone calorimetry. Results demonstrated that the formation of combustible gases was mainly determined by the thermal decomposition stage occurred in the temperature range of 150–600 °C. The incorporation of MP into RTS influenced the release of fuel gases and the char formation in the process of the thermal decomposition of RTS, and eventually retarded the flammability and combustibility of RTS.     

Analysis of Vinyl Chloride in Vapor Phase of Mainstream Cigarette Smoke by GC–MS Under ISO and Health Canada Intensive Machine Smoking Regimens

Vinyl chloride (VC) in the vapor phase of mainstream cigarette smoke was determined under both International Organization for Standardization (ISO) and Health Canada intensive (HCI) machine smoking regimens, which was suspected to be carcinogenic compound. VC was collected by passing the mainstream cigarette smoke through a Cambridge Filter Pad (CFP) into cryogenic traps containing methanol. The impinger solutions were fortified with VC-d ₃ and analyzed by GC–MS. Limits of detection for vinyl chloride was 0.9 ng mL⁻¹ with the recovery in the range of 93.2–98.4 %. Moreover, the intra-day and inter-day precision was 7.39 and 9.77 %, respectively. Under HCI machine smoking regimen, the vinyl chloride yields in vapor phase of mainstream cigarette smoke were much higher and the average increase was greater than 100 % compared with those under ISO smoking condition.

     

Gas chromatography-mass spectrometry of carbonyl compounds in cigarette mainstream smoke after derivatization with 2,4-dinitrophenylhydrazine

An improved gas chromatography-mass spectrometry (GC-MS) method was described for the analysis of carbonyl compounds in cigarette mainstream smoke (CMS) after 2,4-dinitrophenylhydrazine (DNPH) derivatization. Besides formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, methyl ethyl ketone, butyraldehyde, and crotonaldehyde that are routinely analyzed in cigarette smoke, this technique separates and allows the analysis of several C4, C5 and C6 isomeric carbonyl compounds. Differentiation could be made between the linear and branched carbon chain components. In cigarette smoke, the branched chain carbonyls are found at higher level than the linear chain carbonyls. Also, several trace carbonyl compounds such as methoxyacetaldehyde were found for the first time in cigarette smoke. For the analysis, cigarette smoke was collected using DNPH-treated pads, which is a simpler procedure compared to conventional impinger collection. Thermal decomposition of DNPH-carbonyl compounds was minimized by the optimization of the GC conditions. The linear range of the method was significantly improved by using a standard mixture of DNPH-carbonyl compounds instead of individual compounds for calibration. The minimum detectable quantity for the carbonyls ranged from 1.4 to 5.6 microg/cigarette.     

Fluorescence Evaluation of Scavenging Efficiency of Antioxidants Against Reactive Oxygen Species (ROS) in Cigarette Smoke

Cigarette smoke can cause cellular oxidative stress that contributes to various adverse health effects associated with smoke exposure, partially due to reactive oxygen species (ROS) present in cigarette smoke. Reduction of abundant ROS in the cigarette mainstream smoke (MSS) is of importance for human health. In this work, a simple, rapid, and reliable fluorescence evaluation of scavenging efficiency of antioxidants as potential filter additives against ROS in cigarette smoke is reported. This method was based on the combination of model glass reactor and a fluorescence assay of ROS in cigarette smoke using dihydrorhodamine 6 G (DHR-6 G). The antioxidant was added into a glass reactor attached to cigarette filter, which simplified the preparation of combined filter containing additives. The ROS scavenging efficiency of antioxidants was then determined using spectrofluorimetry by the change in fluorescence intensity of whole smoke-bubbled solutions before and after addition of antioxidants into the glass reactor. The proposed method was successfully applied to the determination of ROS scavenging efficiency of several potential additives, such as tert-butylhydroquinone (TBHQ), vitamin C, β-carotene, grape seed extract, and Ginkgo biloba extract. Moreover, the relationship between MSS ROS scavenging efficiency and antioxidant activities (DPPH radicals scavenging efficiency and Fe²⁺ reducing power) of these compounds was also investigated.     

Separation and quantitation of phenolic compounds in mainstream cigarette smoke by capillary gas chromatography with mass spectrometry in the selected-ion mode

Cigarette smoke condensate is a complex chemical matrix and determination of phenolic compounds in it frequently requires extensive and laborious sample preparation. By utilizing derivatization techniques and capillary column gas chromatography with mass spectrometry in the selected-ion mode, separation and quantitation of selected phenolic compounds found in mainstream cigarette smoke can be accomplished with minimal sample preparation. This method has been used to determine concentrations of phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol and hydroquinone in cigarette smoke condensate from a number of commercially available cigarettes and a new cigarette which heats, but does not burn, tobacco. Unlike tobacco-burning cigarettes, levels of the phenolic compounds in the new cigarette smoke are at or below the detection limits for most of the compounds. This result is attributed to the unique design of the new cigarette.     

A high-performance liquid chromatographic determination of major phenolic compounds in tobacco smoke

A high-performance liquid chromatographic (HPLC) method is developed that simultaneously quantifies the dihydroxy compounds hydroquinone, resorcinol, and catechol and the monohydroxy compounds phenol, m + p-cresol and o-cresol in cigarette smoke. Particulate matter samples collected on Cambridge pads and in impingers by conventional trapping techniques are simply (no derivatization required) subjected to reversed-phase gradient liquid chromatography. Samples of both mainstream and sidestream smoke can be analyzed. Selective fluorescence detection is used to monitor the mobile phase effluent, by which these phenolic compounds are detected in the nanogram range. The detector response is linear, overall precision is good, and recoveries are greater than 95 percent. The total run time, excluding extraction, is one hour. The procedure has been applied to tobacco products whose smoke contains varying amounts of these phenols. Kentucky Reference Cigarette 1R4F was found to contain substantially more of these compounds than a new cigarette that heats but does not burn tobacco (New Cigarette). The method is compared with other procedures used to determine phenolics in cigarette smoke.     

卷烟主流烟气中8种羰基化合物的超高效液相色谱测定

建立了超高效液相色谱(UPLC）对卷烟主流烟气总粒相物中甲醛、乙醛、丙酮、巴豆醛等8种羰基化合物的测定方法。采用经2,4-二硝基苯肼酸性溶液处理过的剑桥滤片捕集烟气,再用含2%(体积分数）吡啶的乙腈溶液进行萃取,以KinetexTM C18(150 mm×2.1 mm,2.6 μm）为色谱柱,水-乙腈(35∶65）和水-乙腈-四氢呋喃-异丙醇(59∶30∶10∶1）为流动相梯度洗脱,采用二极管阵列检测器进行检测,分析时间为20 min。结果表明,该方法的相关系数r2≥0.999 97,检出限为25.81~67.74 ng/cig,平均加标回收率为95%~99%,相对标准偏差为1.4%~5.8%。各组分峰分离度高、分析时间短、流动相耗量少、结果准确可靠。用该方法对20种不同卷烟牌号样品中8种羰基化合物的含量进行测定,结果满意。     

Study on the effect of potassium lactate additive on the combustion behavior and mainstream smoke of cigarettes

The influence of potassium lactate (PL) on the combustion behavior and semi-volatile compounds of tobacco during smoking is investigated in this study. The addition of PL showed no effect on the content of total particulate matter, nicotine-free dry particulate matter, puff number, and nicotine. Meanwhile, a 22.5 % increase in moisture content and 3 % decrease in CO content of mainstream smoke were observed when the added amount of PL was up to 2 %. The differential thermogravimetric curves indicated that PL decreased the maximum combustion rate and influenced the thermal degradation stage of tobacco by shifting the peak point of temperature to a higher value. The gas evolution profiles obtained from Fourier transform infrared spectroscopy during combustion showed that PL could lower the CO and CO₂ yield, but did not affect the generation of CH₄ and carbonyl compounds. A great variation in semi-volatile components of the mainstream smoke was also observed from the tobacco containing PL compared with the control. The comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry analysis showed that PL increased the yield of alcohols, lactons, miscellaneous oxygenated compounds and amides, but decreased that of aldehydes, acids, pyrroles and pyrazines. A small added amount (0.2 %) of PL reduced the content of total semi-volatile substances, ketones, esters, phenols, hydrocarbons, pyridines, tobacco alkaloids, and nitrogenous compound. However, the contents of these substances were not affected when the added amount was >0.2 %. PL bound the ash during combustion, thereby leading to the change of combustion behavior and certain smoke components.     

Determination of Acrylamide and Acrolein in Smoke from Tobacco and E-Cigarettes

Acrylamide and acrolein are two short-chained hazardous compounds with neurotoxic, carcinogenic, and mutagenic effects. The aim of this paper is to describe a fast and simple procedure for simultaneous determination of both acrylamide and acrolein under standard conditions, suggest a suitable calibration protocol for custom analysis, and demonstrate its applicability to the analysis of gaseous products from, e.g., cigarettes, cigars, or electronic cigarettes. A gas chromatography–mass spectrometry (GC–MS) method was developed to quantify acrylamide and acrolein in smoke vapor from electronic cigarettes, tobacco cigarettes, and cigars. Nonionic and highly polar molecules with a low boiling point and molecular mass need a suitable derivatization method to achieve appropriate retention and selectivity on commonly used relatively nonpolar stationary phases and to enhance the molecular mass for easy MS detection. The derivatization of acrylamide and acrolein was carried out by a bromination method with elemental bromine. The dibromo derivatives were extracted into an organic solvent and following a dehydrobromination procedure the samples were injected into the GC–MS system. Important experimental parameters were varied, after which the bromination time was defined as 30 min, and the injector temperature and the starting temperature of gradient were set at 280 and 50 °C respectively. Acrolein was found in all tested samples, while acrylamide was detected only in smoke from normal tobacco. Possible mechanisms for the formation of these unsaturated compounds in the samples are discussed. After its validation the newly developed method was successfully and reliably applied to the analysis of both compounds. This short method provides an easy way to determine acrylamide and acrolein in gaseous samples.