顶空-气相色谱法测定卷烟主流烟气中的氰化氢

为测定卷烟主流烟气中的氰化氢,以次氯酸钠为衍生化试剂,建立了顶空-气相色谱的检测方法,采用该方法测定了10种不同焦油卷烟样品,并与连续流动法和离子色谱法的测定结果进行了比较.结果表明:①稀释后的主流烟气气相吸收液和粒相萃取液在12h内较稳定,测定结果变化率小于5.0％;②方法的检出限为0.032 μg/支,精密度(RSD)为3.9％,CN-的加标回收率在102.5％～107.2％之间;③该方法的测定结果比连续流动法高3.31％～5.87％,与离子色谱法的测定结果无显著性差异.     

卷烟侧流烟气中有害醛酮类化合物的分析

为了测定卷烟侧流烟气中的有害醛酮类化合物,考察了卷烟侧流烟气捕集装置各部分对8种有害醛酮的捕集量和样品处理方法对其测定量的影响,建立了捕集、处理及高效液相色谱法检测卷烟侧流烟气中8种有害醛酮类的方法,并采用该方法测定了市售国内外21种卷烟样品侧流烟气中这8种有害醛酮的释放量。结果表明:所测卷烟样品侧流烟气中8种醛酮的总释放量在3300～4600μg/支之间。其中,乙醛释放量最高,在1600～2300μg/支之间;丙酮和甲醛次之,释放量在400～800μg/支之间;而其他5种醛酮的释放量在70～250μg/支之间。     

连续流动法测定卷烟主流烟气中的HCN释放量

为快速准确地测定卷烟主流烟气的HCN释放量,考察了烟气捕集方式、显色温度、时间和缓冲溶液pH值、14种阴离子和15种阳离子、样品溶液的放置时间对基于异烟酸—1,3-二甲基巴比妥酸显色体系的连续流动法测定结果的影响,与吡啶—吡唑啉酮显色法进行了比较,并采用该法测定了50个国产卷烟样品主流烟气的HCN释放量。结果表明:①采用剑桥滤片和一个盛有30mL0.1 mol/L NaOH水溶液的吸收瓶分别捕集烟气粒相和气相物的效率最高,HCN的回收率和RSD分别为99.1%和4.3%;②在高于15℃的室温下反应8min达到最大吸收;③pH5.3邻苯二甲酸氢钾缓冲溶液比较适宜;④HCN测定量不受烟气中的痕量阴、阳离子的影响;⑤样品吸收液在制成后6h内较稳定;⑥异烟酸—1,3-二甲基巴比妥酸显色法与吡啶—吡唑啉酮法的测定结果没有显著性差异,但前者较后者安全环保、稳定性好、操作简单、灵敏度高、重复性好;⑦50个牌号国产卷烟样品主流烟气中的HCN释放量在26~147μg/支之间,烤烟型和混合型卷烟烟气HCN平均释放量分别为93.8和63.6μg/支。该法适合于批量卷烟样品主流烟气中HCN含量的快速分析。     

卷烟主流烟气粒相物和气相物pH值的测定

为了同时测定卷烟主流烟气粒相物和气相物pH值,研究了抽吸烟支数、抽吸容量、萃取液或吸收液浓度和体积、萃取振荡时间、萃取振荡频率以及空白萃取液和吸收液的酸碱性对粒相物和气相物pH值测定结果的影响.结果表明:①适宜条件为吸烟机抽吸容量40 mL,抽烟支数15支;烟气粒相物萃取液50%异丙醇水溶液;萃取液体积80 mL,振荡频率175 r/min,振荡萃取时间30 min,烟气气相物吸收液50%异丙醇水溶液,吸收液体积100 mL;②方法的RSD为0.20%～0.27%;③空白萃取液和吸收液呈碱性,对烟气粒相物和气相物pH值测定值均有影响.该方法可用于烟气粒相物和气相物pH值的测定.     

卷烟主流烟气中挥发性醛酮的LC-MS/MS分析

采用2,4-二硝基苯肼衍生-LC-MS/MS法测定了32种卷烟样品主流烟气中的甲醛、乙醛、丙烯醛、丙酮、丙醛、巴豆醛、甲基丙烯醛、2-丁酮、丁醛、苯甲醛、戊醛、己醛.结果表明:①方法的检测限为0.1～0.5 ng/mL,回收率在91.6%～100.3%之间,相对标准偏差为3.28%～7.86%;②卷烟样品主流烟气的挥发性醛酮成分中主要为乙醛和丙酮,苯甲醛、已醛含量较小;③与进口烟相比,国产烤烟型卷烟主流烟气中的挥发性醛酮含量相对较高,混合型卷烟的相对较低;④不管是烤烟型还是混合型,焦油量高的卷烟主流烟气中的挥发性醛酮含量均相对较高.     

主流烟气中氨与部分羰基化合物的偏相关分析及应用

为提高离子色谱(IC)法测定卷烟主流烟气中氨的待测液的稳定性,分析了57种卷烟主流烟气中氨与部分挥发性羰基化合物(甲醛、乙醛、丙酮、丙烯醛、丙醛、巴豆醛和2-丁酮)的偏相关性;根据偏相关分析结果,以甲醛-HCl混合溶液(甲醛质量分数为15%,HCl物质的量浓度为100 mmol/L)作为萃取液对现行的检测方法(YC/T 377—2010)进行了改进,并考察了5种卷烟样品氨待测液的稳定性。结果表明:1主流烟气中的氨与甲醛呈极显著负相关,且二者在氨的待测溶液中会协同升高;2改进现有IC方法的萃取液后,5种卷烟样品的氨待测液经过24 h仍然比较稳定;3方法改进后,检出限为0.30μg/支,加标回收率为97.05%~102.40%,日间相对标准偏差(RSD)为1.28%。该方法较好地解决了待测液氨检测结果随时间不断升高的问题,适用于分析卷烟主流烟气中氨的释放量。     

气相色谱法分析卷烟烟气中的醛类化合物

本文研究了采用毛细管气相色谱仪分析卷烟烟气中醛类化合物的方法。在标准条件下吸烟,使卷烟烟气通过装有2,4-二硝基苯肼(DNPH)衍生化试剂酸性溶液的捕集装置,烟气中的醛类化合物与DNPH反应,生成稳定的2,4-二硝基苯腙衍生物,经三氯甲烷萃取,并在氮气保护下浓缩后,采用配备氮-磷检测器(NPD)的毛细管气相色谱仪进行分析。本文评价了该方法测定卷烟烟气中甲醛、乙醛和丙烯醛的重复性及回收率,并采用内标法定量测定了9种牌号卷烟烟气中的甲醛、乙醛和丙烯醛的输送量以及卷烟滤嘴对甲醛的截滤效率。采用气/联用仪(GC/S)和标样加入法鉴定出卷烟烟气中的12种醛类化合物。该方法操作简便,重复性好,回收率高,适用于卷烟烟气中醛类化合物的分析。      

剑桥滤片-液-液捕集系统各部分烟气捕集物的细胞毒性比较

为考察烟气捕集在卷烟主流烟气体外细胞毒性检测中的作用,采用3种捕集系统:剑桥滤片-pH7.0 PBS-丙酮、剑桥滤片-pH7.2 PBS-乙酸乙酯和剑桥滤片-pH7.4 PBS-70％甘油捕集同一卷烟主流烟气的粒相物和气相物,用中性红细胞毒性法检测了各部分烟气捕集物对中国仓鼠卵巢细胞(CHO)的毒性作用,气相色谱-质谱法检测了3种有机溶剂烟气捕集物的化学成分.结果表明:①细胞毒性的大小顺序为:剑桥滤片捕集物＞ PBS捕集物＞有机溶剂捕集物;②在第2级捕集物中,pH7.4 PBS烟气捕集物的细胞毒性显著大于pH7.0和pH7.2 PBS烟气捕集物;③在第3级捕集物中,70％甘油烟气捕集物的细胞毒性最大,丙酮和乙酸乙酯的较小,且二者比较接近;④3种有机溶剂捕集的烟气气相物部分主要是醛类、酯类、烷烃和苯系物,70％甘油捕集了较多的烷烃和苯系物.剑桥滤片捕集的烟气冷凝物反映了部分烟气对CHO细胞的中性红细胞毒性,剑桥滤片-pH7.4 PBS溶液-70％甘油捕集的烟气物质可以较全面地反映烟气的细胞毒性.     

卷烟主流烟气气相水分的捕集及其卡尔·费休法测定

为了解烟气水分对卷烟吸味的影响,以异丙醇和乙醇作吸收液,采用两级碰撞取样器串联捕集烟气气相物,卡尔·费休法测定了20种国产品牌卷烟样品烟气粒相水分和气相水分.结果表明:①微量水检测限为0.35 mg/mL,回收率＞95%,粒相水分和气相水分的RSDs分别为3.5%和4.5%;②卷烟样品烟气粒相水分和气相水分的含量范围分别为1.33～3.01和3.71～8.89 mg/支.主流烟气气相水分可能是影响卷烟抽吸品质的一个重要指标.     

超高效液相色谱快速测定卷烟主流烟气中7种挥发酚

为快速准确地测定卷烟烟气中的对-苯二酚、邻-苯二酚、间-苯二酚、苯酚、对-甲酚、邻-甲酚和间-甲酚,建立了同时测定卷烟主流烟气中7种挥发酚的超高效液相色谱( UPLC)方法.采用1％醋酸水溶液对捕集烟气粒相物的剑桥滤片超声萃取20 min,萃取液过滤后通过Acquity UPLC BEH C18色谱柱分离,以水相中含7.0×10-3 mol/Lβ-环糊精(β-CD)的流动相进行梯度洗脱,采用荧光检测器进行分析.该方法的相对标准偏差( RSD)为1.15％～5.79％,回收率为90％～102％,检测限为0.04 ～ 0.35 μg/支,分析时间9 min.该法适合批量卷烟主流烟气中7种挥发酚的快速分析.     

卷烟主流烟气主要挥发性羰基物的模拟口腔沉积

采用卷烟烟气口腔沉积模拟装置,对25种卷烟样品主流烟气主要挥发性羰基物的模拟口腔沉积情况进行了分析。结果表明:①各挥发性羰基物分析结果的日内、日间相对标准偏差均小于15%,大部分小于10%,模拟装置对挥发性羰基物的口腔沉积分析的稳定性良好。②不同挥发性羰基物的口腔沉积量由大到小依次为乙醛、甲醛、丙酮、丙醛、丙烯醛、丁醛、巴豆醛和2-丁酮,其中,甲醛和乙醛的沉积量显著高于其他挥发性羰基物;沉积比例由高到低依次为甲醛、乙醛、丙醛、丁醛、巴豆醛、丙烯醛、丙酮和2-丁酮。③烟气口腔刺激与甲醛、乙醛口腔沉积量显著负相关,相关系数分别为-0.916、-0.934,P值均小于0.01。      

两种抽吸模式下卷烟烟气有害成分释放量与滤嘴通风率的关系

为了解不同抽吸模式下卷烟烟气有害成分释放量与滤嘴通风率的关系,考察了ISO和加拿大卫生部深度(HCI)两种抽吸模式下主流烟气中烟碱及乙醛、丙烯醛、苯、苯并[a]芘、1,3-丁二烯、一氧化碳(CO)、甲醛、N-亚硝基降烟碱(NNN)、4-(N-甲基-N-亚硝氨基)-1-(3-吡啶基)-1-丁酮(NNK)、苯酚、巴豆醛、氢氰酸(HCN)和氨等13种有害成分的释放量与滤嘴通风率的相关关系,并进一步探讨了单位烟碱有害成分释放量与滤嘴通风率的相关性。结果表明:①在ISO抽吸模式下,除NNN、NNK外,其他有害成分的释放量与滤嘴通风率负相关;甲醛和巴豆醛的单位烟碱释放量与滤嘴通风率负相关,乙醛、CO、苯并[a]芘和氨的单位烟碱释放量与滤嘴通风正相关。②在HCI抽吸模式下,甲醛、巴豆醛、苯并[a]芘、苯酚和烟碱的释放量与滤嘴通风率负相关,HCN释放量与滤嘴通风率正相关,其余有害成分的释放量与滤嘴通风无显著相关性;乙醛、丙烯醛、巴豆醛、CO、HCN和氨的单位烟碱释放量与滤嘴通风率正相关。      

丙三醇热裂解形成羰基化合物机理研究

采用密度泛函理论,研究丙三醇各种反应途径的热力学和动力学性质,确定丙三醇裂解的主要裂解路径。结果发现：丙三醇主要通过脱水反应形成甲醛、乙醛和丙烯醛,反应活化能在53～65kcal/mol。将丙三醇的裂解机理应用于1,2-丙二醇和1,3-丙二醇,推导1,2-丙二醇的主要裂解产物是丙醛、丙酮和乙醛,而1,3-丙二醇的主要裂解产物是甲醛、乙醛和丙烯醛。无氧裂解实验与理论推导具有高度一致性。     

HPLC法同时测定食品接触橡胶密封垫圈中3种醛类化合物迁移量

目的:建立一种利用HPLC同时测定食品接触橡胶密封垫圈中甲醛、乙醛和丙烯醛迁移量的分析方法。方法:以4%乙酸水溶液、10%乙醇水溶液、20%乙醇水溶液、50%乙醇水溶液及橄榄油作为食品模拟物,按GB 5009.156—2016进行迁移试验,经衍生化反应后,采用Accucore RP-MS色谱柱分离,以乙腈—水溶液为流动相等度洗脱,紫外检测器检测。结果:3种醛类化合物在0.05~5.00 mg/L内呈良好的线性关系,相关系数R²≥0.9983。甲醛、乙醛和丙烯醛检出限分别为0.58,0.62,1.68 mg/kg;定量限分别为0.98,0.99,2.93 mg/kg,在1.0~15.0 mg/kg添加水平范围内,3种醛类化合物回收率为81.0%~103.3%;相对标准偏差为0.78%~7.05%。结论:该方法适用于食品接触橡胶密封垫圈中醛类化合物迁移量的检测。     

卷烟主流烟气中羰基化合物的改进分析方法

选择2,4-二硝基苯肼作为羰基化合物的衍生化试剂,采用高效液相色谱(HPLC)分析卷烟烟气中主要8种羰基化合物。卷烟主流烟气通过经2,4-二硝基苯肼(DNPH)酸性溶液处理的剑桥滤片进行捕集,烟气中的羰基化合物与DNPH反应生成相应的2,4-二硝基苯腙衍生物,经乙腈萃取后,采用配备紫外检测器的高效液相色谱进行定量分析。与以往的分析方法相比,该方法防止了丙烯醛衍生化合物的进一步反应,提高了分析的准确性。评价了该方法测定烟气中8种羰基化合物的重复性、回收率及检测限,采用该方法测定了肯塔基参考卷烟2R4F和部分国内外卷烟。      

On-road emissions of carbonyls from light-duty and heavy-duty vehicles

Vehicle emissions are a major source of carbonyls, which play an important role in atmospheric chemistry and urban air quality. Yet, little data are available for speciated carbonyls emitted by vehicles and especially by heavy-duty diesel vehicles. On-road vehicle emissions of carbonyls have been measured in May 1999 at the Tuscarora Mountain Tunnel, PA. Ten saturated aliphatic aldehydes, 4 saturated aliphatic ketones, 4 unsaturated aliphatic carbonyls, 4 aliphatic dicarbonyls, and 9 aromatic carbonyls have been identified and their concentrations measured. For light-duty (LD) vehicles, total carbonyl emissions were ca. 6.4 mg/km, and the 10 largest emission factors were, in decreasing order, those of formaldehyde (2.58 +/- 1.05 mg/km, ca. 40% of total carbonyls), acetone, acetaldehyde, heptanal, crotonaldehyde, 2-butanone, propanal, acrolein, methacrolein, and benzaldehyde. For weight class 7-8 heavy-duty diesel vehicles (7-8 HD), total carbonyl emissions were ca. 26.1 mg/km, and the 10 largest emission factors were, in decreasing order, those of formaldehyde (6.73 +/- 2.05 mg/km, ca. 26% of total carbonyls), acetaldehyde, acetone, crotonaldehyde, m-tolualdehyde, 2-pentanone, benzaldehyde, a C5 saturated aliphatic aldehyde isomer, 2,5-dimethylbenzaldehyde, and 2-butanone. Aromatic carbonyls, unsaturated aliphatic aldehydes, and aliphatic dicarbonyls represented larger fractions of the total carbonyl emissions for 7-8 HD vehicles than for LD vehicles. For HD vehicles, formaldehyde and acetaldehyde emission factors measured in this study are ca. 4-5 times lower than those measured in previous work. For LD vehicles, emission factors measured in this study are generally lower than those measured in earlier work and are about the same, within reported uncertainties, as those measured in 1992 in the same highway tunnel.     

Emissions of aldehydes and ketones from a two-stroke engine using ethanol and ethanol-blended gasoline as fuel

Besides aliphatic gasoline, ethanol-blended gasoline intended for use in small utility engines was recently introduced on the Swedish market. For small utility engines, little data is available showing the effects of these fuels on exhaust emissions, especially concerning aldehydes and ketones (carbonyls). The objective of the present investigation was to study carbonyl emissions and regulated emissions from a two-stroke chain saw engine using ethanol, gasoline, and ethanol-blended gasoline as fuel (0%, 15%, 50%, 85%, and 100% ethanol). The effects of the ethanol-blending level and mechanical changes of the relative air/fuel ratio, lambda, on exhaust emissions was investigated, both for aliphatic and regular gasoline. Formaldehyde, acetaldehyde, and aromatic aldehydes were the most abundant carbonyls in the exhaust. Acetaldehyde dominated for all ethanol-blended fuels (1.2-12 g/kWh, depending on the fuel and lambda), and formaldehyde dominated for gasoline (0.74-2.3 g/kWh, depending on the type of gasoline and lambda). The main effects of ethanol blending were increased acetaldehyde emissions (30-44 times for pure ethanol), reduced emissions of all other carbonyls exceptformaldehyde and acrolein (which showed a more complex relation to the ethanol content), reduced carbon monoxide (CO) and ntirogen oxide (NO) emissions, and increased hydrocarbon (HC) and nitrogen dixodie (NO2) emissions. The main effects of increasing lambda were increased emissions of carbonyls and nitrogen oxides (NOx) and reduced CO and HC emissions. When the two types of gasoline are considered, benzaldehyde and tolualdehyde could be directly related to the gasoline content of aromatics or olefins, but also acrolein, propanal, crotonaldehyde, and methyl ethyl ketone mainly originated from aromatics or olefins, while the main source for formaldehyde, acetaldehyde, acetone, methacrolein, and butanal was saturated aliphatic hydrocarbons.     

Determination of airborne carbonyls: comparison of a thermal desorption/GC method with the standard DNPH/HPLC method

The standard method for the determination of gaseous carbonyls is to collect carbonyls onto 2,4-dinitrophenyl hydrazine (DNPH) coated solid sorbent followed by solvent extraction of the solid sorbent and analysis of the derivatives using high-pressure liquid chromatography (HPLC). This paper describes a newly developed approach that involves collection of the carbonyls onto pentafluorophenyl hydrazine (PFPH) coated solid sorbents followed by thermal desorption and gas chromatographic (GC) analysis of the PFPH derivatives with mass spectrometric (MS) detection. Sampling tubes loaded with 510 nmol of PFPH on Tenax sorbent effectively collect gaseous carbonyls, including formaldehyde, acetaldehyde, propanal, butanal, heptanal, octanal, acrolein, 2-furfural, benzaldehyde, p-tolualdehyde, glyoxal, and methylglyoxal, at a flow rate of at least up to 100 mL/min. All of the tested carbonyls are shown to have method detection limits (MDLs) of subnanomoles per sampling tube, corresponding to air concentrations of <0.3 ppbv for a sampled volume of 24 L. These limits are 2-12 times lower than those that can be obtained using the DNPH/HPLC method. The improvement of MDLs is especially pronounced for carbonyls larger than formaldehyde and acetaldehyde. The PFPH/GC method also offers better peak separation and more sensitive and specific detection through the use of MS detection. Comparison studies on ambient samples and kitchen exhaust samples have demonstrated that the two methods do not yield systematic differences in concentrations of the carbonyls that are above their respective MDLs in both methods, including formaldehyde, acetaldehyde, acrolein, and butanal. The lower MDLs afforded by the PFPH/ GC method also enable the determination of a few more carbonyls in both applications.     

Speciated ambient carbonyls in Rio de Janeiro, Brazil

Carbonyls in urban air continue to receive scientific and regulatory attention as toxic air contaminants and for their important role in photochemical smog. However, few data are available for speciated carbonyls in urban air. Ambient concentrations of up to 61 carbonyls have been measured in Rio de Janeiro, Brazil. The most abundant carbonyls were formaldehyde and acetaldehyde (study-averaged concentrations of 10.8 +/- 4.1 and 10.4 +/- 4.6 microg m(-3), respectively, in samples of 3-h duration collected from May to November 2000 at a downtown location during the morning vehicle commute) followed by acetone, 2-butanone, and benzaldehyde. Ambient concentrations of other carbonyls (except acetophenone) correlated well with those of acetaldehyde and of formaldehyde. This study examines the ambient acetaldehyde/ambient formaldehyde concentration ratio in Brazilian cities since the mid-1980s in the context of changes in Brazil's reliance on ethanol as a vehicle fuel. This ratio has begun to decrease in recent years due to fleet turnover and is likely to decrease further as older cars fueled with ethanol are replaced by lower-emitting models that run on a gasoline-ethanol blend. The carbonyls measured are ranked with respect to ozone formation potential (using MIR coefficients) and reaction with OH (using carbonyl-OH reaction rate constants). Ozone formation is dominated by formaldehyde (43% of total) followed by acetaldehyde (32%) and methylglyoxal (8%); other carbonyls each contributed < or = 4% of total. For reaction with OH, acetaldehyde ranks first closely followed by formaldehyde.