气相色谱－串联质谱法测定电子烟烟液中的10种生物碱含量

建立了一种气相色谱－串联质谱法测定电子烟烟液中10种生物碱含量的分析方法,并对仪器分析条件、样品前处理条件等进行了优化。样品加入2.0 mL 2% NaOH水溶液后,以10 mL二氯甲烷-甲醇溶液（体积比4∶1）为萃取溶液,涡旋振荡萃取30 min,萃取液经无水硫酸镁除水后,以气相色谱－串联质谱法多反应监测（MRM）模式检测。结果显示：在优化条件下,烟碱及9种次要生物碱在25～1 000 μg/mL及0.002 5～20 μg/mL范围内呈良好的线性,相关系数（r2）不低于0.997,3个加标水平下的回收率为87.9%～109%,日内及日间精密度（RSD）分别不高于6.8%和7.9%,检出限（LOD）为0.0040～0.10 mg/kg,定量下限（LOQ）为0.013～0.33 mg/kg。用该方法测定23种品牌共计171种型号电子烟烟液中10种生物碱含量,结果发现,电子烟烟液中的烟碱含量为2.16～23.73 mg/g,9种次要生物碱的含量中位值为0.06～7.35 mg/kg,检出率为64.91%～99.42%,其中9种电子烟烟液样品的总次要生物碱含量与烟碱含量比例大于1.0%。该方法灵敏度高、准确性好、重复性好,完全满足电子烟烟液样品中10种生物碱的检测要求。     

基质固相分散-全二维气相色谱-质谱法分析电子烟烟液中的化学成分EI北大核心CSCD

建立了基质固相分散-全二维气相色谱-飞行时间质谱(MSPD-GC×GC-TOFMS)检测电子烟烟液中化学成分的分析方法。采用硅藻土为分散剂处理电子烟烟液,以二氯甲烷为提取溶剂震荡提取其中的化学成分,提取溶液用GC×GC-TOFMS分析。结果表明:基质固相分散方法可有效降低样品基质中丙二醇和丙三醇对目标成分的干扰;全二维气相色谱具有更高的分辨率和灵敏度,分析结果更可靠;方法重复性好,各成分测定的相对标准偏差小于9.9%;方法准确度高,考察了6种化合物的加标回收率在90.8%~114.8%之间。     

气相色谱法测定电子烟烟液及气溶胶中双乙酰和乙酰丙酰

建立气相色谱法氢火焰离子化检测器测定电子烟烟液和气溶胶中双乙酰和乙酰丙酰含量的方法。样品以20 mL乙醇为萃取剂,涡旋振荡萃取10 min,采用气相色谱外标法进行定量分析。双乙酰和乙酰丙酰质量浓度在0.5~50 μg/mL范围内与色谱峰面积呈良好的线性关系,相关系数分别为0.999 6、0.999 4,方法检出限分别为0.044、0.052 μg/mL。烟液中双乙酰和乙酰丙酰测定结果的相对标准偏差为2.5%~4.3%(n=6),样品加标回收率为95.0%~102.5%;气溶胶中双乙酰和乙酰丙酰测定结果的相对标准偏差为3.1%~4.6%(n=6),样品加标回收率为92.7%~102.3%。气溶胶中双乙酰和乙酰丙酰理论浓度与实测浓度具有较强的相关性(对于双乙酰r~2=0.990 1,对于乙酰丙酰r~2=0.994 7),说明双乙酰、乙酰丙酰烟液通过雾化直接转移至气溶胶中。该方法准确度高,重现性好,检出限低,可满足电子烟样品的检测需求。     

离子色谱法测定电子烟烟液中氨的含量

建立了测定电子烟烟液中的氨含量离子色谱法。样品经10 mol·L-1盐酸溶液萃取10 min后,采用Dionex Ion Pac CS16A阳离子交换柱分离,以MSA为淋洗液进梯度洗脱,用电化学检测器检测。氨的质量浓度在0.05~1.0 mg·L-1范围内与峰面积呈线性关系,检出限(3S/N)为0.035μg·g-1,测定下限(10S/N)为0.12μg·g-1。方法用于12种市售品牌电子烟烟液中氨的测定,加标回收率在93.2%~106%之间,测定值的相对标准偏差(n=5)小于4%。     

高效液相色谱法测定电子烟烟液及气溶胶中茄尼醇含量

建立了高效液相色谱法测定电子烟烟液及气溶胶中茄尼醇的含量。电子烟气溶胶中的茄尼醇使用剑桥滤片捕集,烟液及滤片分别经甲醇振荡萃取后,直接进行高效液相色谱测定。结果表明:茄尼醇在0.016~8.11μg/mL浓度范围内线性关系良好(R2=0.9993),烟液及气溶胶在3个加标水平的回收率在97.06%~104.39%之间,相对标准偏差不高于1.06%,检出限为0.010μg/g。实际样品测试表明:电子烟烟液中的茄尼醇含量在0.014~25.67μg/g,检出率为64.21%;在一定的抽吸模式下,对于茄尼醇含量为25.67μg/g的烟液,8种电子烟产品抽吸150口的气溶胶茄尼醇释放量为2.62~10.12μg。     

气相色谱-质谱法同时测定烟用辅材中邻苯二甲酸酯与己二酸酯

提出了用气相色谱-质谱法同时测定烟用辅材中7种邻苯二甲酸酯类和4种己二酸酯类增塑剂的含量。样品用异丙醇-环己烷（3+2）溶液超声提取,通过DB-5MS色谱柱分离,采用选择离子监测模式进行测定。11种增塑剂的质量浓度均在0.012～1.2 mg·L^-1浓度范围内与其峰面积呈线性关系,方法的检出限（3S/N）在0.022～0.038μg·g^-1之间。以不同种类的烟用辅材样品为基体,在3个浓度水平下进行回收试验,方法的回收率在84.0%～112%之间,测定值的相对标准偏差（n=5）在3.2%～8.5%之间。     

气相色谱法分析电子烟烟液中主要生物碱含量

建立了电子烟烟液中主要生物碱含量的气相色谱测定方法,并对19种品牌电子烟共计51种型号电子烟烟液进行含量分析。电子烟烟液经超声稀释提取后,直接进行气相色谱分析。采用HP-50+型毛细管色谱柱,氢火焰离子化检测器检测,内标法定量。结果表明:上述化合物在各自浓度范围内线性关系良好(R20.996),3个加标水平的平均回收率在97.1%~104.6%之间,相对标准偏差(RSD)小于4%,检出限为0.00037%~0.0011%。实际样品测试结果表明:电子烟烟液中烟碱含量在0~28.36mg/mL,生产厂商所标注烟碱浓度差异率为-136.56%~100.00%,微量生物碱含量范围为0~0.045mg/mL,所测定微量生物碱总含量与烟碱含量之比在0~3.50%。     

气相色谱-质谱法测定烟用香精香料中香兰素和乙基香兰素

采用气相色谱-质谱法测定烟用香精香料中香兰素和乙基香兰素的含量。烟用香精香料样品与萃取剂的比例为1g比100mL,在500W下超声萃取10min。在气相色谱分离中用DBWAXETR毛细管柱为固定相,在质谱分析中采用选择离子监测模式。以丙酸苯乙酯为内标物。香兰素和乙基香兰素的线性范围均为0.5~200mg·L-1,检出限(3S/N)分别为0.03,0.02mg·kg-1。加标回收率在91.4%~109%之间,测定值的日内相对标准偏差(n=5)在0.43%~2.2%之间,日间相对标准偏差(n=5)在0.67%~2.6%之间。     

气相色谱-质谱法测定电子烟烟液中的7种溶剂

提出了测定电子烟烟液中乙醇、1,2-丙二醇、丙三醇、二甘醇、三甘醇、四甘醇和五甘醇等7种溶剂的气相色谱-质谱法(GC-MS)。电子烟烟液经甲醇稀释超声提取后,用DB-ALC1毛细管色谱柱(30m×0.32mm,1.8μm)分离,并用GC-MS进行分析,以1,3-丁二醇为内标物,采用内标法定量。7种溶剂的质量浓度与其峰面积在一定范围内呈线性关系,方法的测定下限(10s)为1.1~5.0mg·L~(-1)。加标回收率在91.2%~107%之间,相对标准偏差(n=5)在1.2%~3.5%之间。     

闪蒸-气相色谱指纹图谱及系统聚类分析用于烟用香精香料的测定

采用闪蒸-气相色谱法(FE-GC)对不同黏度的烟用香精香料样品进行测定,考察了影响测定的主要因素。结果表明,0.40 mg样品在350 ℃下进行FE-GC分析,可以得到重现性良好的色谱图。与超声辅助液-液萃取-气相色谱法(ULLE-GC)分析结果的比较表明,FE-GC适用于不同黏度样品的分析。采用该法检测了中等黏度的烟用香精香料1184号8个批次样品,并建立其指纹图谱。利用系统聚类分析法可以明显区分1184号样品及掺兑10%～30%其他种类烟用香精香料的样品。FE-GC法简便、快速、灵敏,适用于不同黏度的烟用香精香料样品的检测和质量控制分析。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.