在线液相-气相二维色谱高灵敏测定卷烟主流烟气中的4-（N-甲基亚硝胺基）-1-（3-吡啶基）-1-丁酮

建立了在线液相-气相二维色谱测定卷烟主流烟气中4-(N-甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)的方法。 NNK 的分析在在线凝胶气质联用仪上进行,采用自行装填的微型碱性氧化铝柱,并把仪器上的凝胶柱换成氧化铝柱,用于 NNK 的分析。捕集有主流烟气总粒相物的剑桥滤片用二氯甲烷提取,以 D4-NNK 为内标,提取液经微型氧化铝柱分离,含 NNK 的部位切割进入气相色谱,排干溶剂后启动气相色谱升温经毛细管柱进行分离,用质谱检测。本方法将烟气国标方法 NNK 测定中的氧化铝柱色谱净化和气相色谱-质谱分析在线连接起来,可不经样品前处理净化直接进样分析;每次进样可达40μL,是常规气相色谱-质谱分析最大进样量(2.0μL)的20倍,显著提高了分析灵敏度。方法线性范围达1.2~120 ng/ mL,相关系数为r=0.9998,回收率为93.9%~96.0%;检出限和定量限分别为0.25 ng/ mL 和0.9 ng/ mL,样品分析结果与中国烟草总公司企业标准方法进行对比,结果相符合。     

中心切割式多维气相色谱/质谱系统中中点限流器的改进及其在卷烟烟气中苯并[a]芘检测中的应用

对多维气相色谱的核心部件中点限流器进行了改进,用一段0.25mm i.d.毛细管柱取代石墨限流管,Y形玻璃压合连接器取代两孔石墨垫,显著提高了一维色谱保留时间的稳定性,保证了中心切割范围的准确性,且消除了石墨对苯并[a]芘的吸附残留。同时,将本系统应用于卷烟烟气中苯并[a]芘的检测。采用剑桥滤片捕集烟气粒相物,环己烷萃取,以氘代苯并[a]芘为内标,直接用中心切割式多维气相色谱/质谱(MDGC/MS)法测定。该法线性关系良好,其线性范围为1.47～29.4μg/L(r2=0.999 9);重复性好,测得实际样品中苯并[a]芘含量的相对标准偏差(RSD)为1.94%;回收率为90.74%～101.86%;检出限和定量限分别为0.31ng/支及1.03ng/支,可以满足检测要求。应用本系统对2R4F参比卷烟烟气中苯并[a]芘进行了检测,结果与文献报道值基本一致。     

固相萃取和气相色谱-质谱法测定主流烟气中苯并[a]芘的研究

提出了一种用于测定主流烟气中痕量苯并[a]芘的方法.以甲醇-正庚烷萃取体系初步处理主流烟气中的总粒相物(TPM),接着以KOH甲醇溶液数毫升洗涤正庚烷萃取液,再将正庚烷萃取液适当浓缩后经过酸化的硅胶固相萃取小柱,流出液用N2吹干后以乙酸乙酯200 μL定容,对苯并[a]芘进行选择离子监测方式下的气相色谱-质谱法定量测定.方法的分离效果及色谱重现性好,可用于复杂体系中痕量组分苯并[a]芘的定量测定.     

在线液相-气相二维色谱-质谱联用法测定烟用香精和料液中苯并[a]芘的含量

样品10.0g,加水10mL稀释,加0.100g·L-1 D12-苯并[a]芘内标溶液200μL,加环己烷10mL,以20 000r·min-1速率漩涡振荡萃取5min。提取液直接进入液相色谱,经微型硅胶柱分离净化,含苯并[a]芘的部位切割进入气相色谱,经毛细管柱分离后进入质谱分析,采用选择离子监测模式(SIM)进行测定。苯并[a]芘的质量浓度在0.08~50ng·L-1范围内与峰面积呈线性关系,方法的检出限(3s)为0.12ng·g-1,在3个不同浓度水平上进行了回收试验,回收率在92.7%~98.1%之间,测定值的相对标准偏差(n=7)在3.2%~3.7%之间。     

固相萃取新装置净化-超高效液相色谱法测定卷烟主流烟气中的苯并[α]芘

研究了用正相固相萃取净化,超高效液相色谱测定卷烟主流烟气中苯并[α]芘的方法。捕集有卷烟主流烟气总粒相物的剑桥滤片置于自主设计的样品萃取瓶中,用环己烷-乙醇(95:5,V/V)超声振荡萃取,提取液用硅胶固相萃取净化,然后以Waters ACQUITY UPLC BEH C18(2.1×50 mm,1.7μm)色谱柱为固定相,甲醇为流动相,超高效液相色谱-荧光检测测定;苯并[α]芘检出限为0.22 ng/支,样品加标回收率为89.6%~95.4%,日内相对标准偏差为3.2%,日间相对标准偏差为3.6%;结果令人满意。     

高效液相色谱法测定生活饮用水中的苯并[a]芘

建立高效液相色谱二极管阵列检测器检测生活饮用水苯并[a]芘的测定方法。采用C18反相色谱柱(150mm×4.6 mm,5μm),在流动相为甲醇–水(体积比为90∶10)、流量1.0 mL/min、检测波长295 nm、柱温35℃、进样体积20μL的条件下测定生活饮用水中苯并[a]芘。该方法检出限为6 ng/L,线性范围0～100 ng/mL,加标回收率为88.1%～93.4%,测定结果的相对标准偏差为1.06%(n=9)。该法样品预处理简单,分离度高,分析时间短,适用于生活饮用水中苯并[a]芘的准确定性定量测定。     

加速溶剂/固液固萃取-气相色谱/质谱法分析卷烟烟气中苯并[a]芘

建立了集萃取与净化于一体的加速溶剂/固液固萃取(AS/SLSE)卷烟烟气中痕量苯并[a]芘(BaP)的样品前处理方法。卷烟烟气经捕集后,用AS/SLSE提取和净化,萃取液浓缩后进行色谱分析。优化了AS/SLSE吸附剂、萃取温度、吹扫体积、静态萃取时间及循环次数等条件。在优化条件下(5 g硅镁型吸附剂、萃取温度100℃、吹扫体积40%、静态萃取时间3 min循环2次,样品连续萃取3次),AS/SLSE-气相色谱/质谱法(GC/MS)分析卷烟烟气中苯并[a]芘方法的检出限为1.0μg/L,回收率为97.1%,相对标准偏差(RSD)为2.5%。方法成功用于卷烟烟气样品的分析,测定结果与国家标准推荐方法吻合。     

全自动固相萃取-气相色谱-串联质谱法测定卷烟主流烟气中的3种多环芳烃

以全自动固相萃取技术净化主流烟气萃取液,建立了卷烟主流烟气中苯并［a］芘、苯并［a］蒽和屈艹 3种多环芳烃的气相色谱-串联质谱(GC-MS/MS)测定方法。以吸烟机抽吸卷烟,并以剑桥滤片捕集卷烟主流烟气,然后以含氘代苯并［a］芘内标的环己烷溶液萃取滤片,萃取液经全自动固相萃取仪净化后以GC-MS/MS分离检测。结果表明,苯并［a］芘、苯并［a］蒽和屈艹 的检出限分别为0.05、0.16和0.23 ng/cig,回收率为91.5%～102.1%,相对标准偏差(RSD)均小于5%。该方法的自动化程度高、操作简便、检出限低、重复性好,适用于卷烟主流烟气中苯并［a］芘、苯并［a］蒽 3种多环芳烃释放量的检测。     

气相色谱质谱法测定化妆品中9种多环芳烃

建立了气相色谱质谱法测定化妆品中9种多环芳烃的分析方法。化妆品中的萘、苯并[a]蒽、、苯并[b]荧蒽、苯并[j]荧蒽、苯并[k]荧蒽、苯并[e]芘、苯并[a]芘、二苯并[a,h]蒽等9种多环芳烃用甲醇超声提取后,用环己烷液-液萃取后浓缩,经硅胶-中性氧化铝柱净化后,采用气相色谱-质谱测定。多环芳烃浓度在0.05～2 mg/L范围内,质量浓度与其峰面积呈良好的线性关系。在低、中、高3个添加水平下,9种多环芳烃化合物的平均回收率为81.6%～100.2%,相对标准偏差为1.3%～5.8%。方法可用于化妆品中多环芳烃的检测。     

一种超临界流体色谱–气相色谱–质谱测定卷烟主流烟气中苯并[a]芘的方法

<正>申请公布号:CN106198796A申请公布日:2016.12.07申请人:云南中烟工业有限责任公司摘要本发明公开了一种超临界流体色谱(SFC)–气相色谱–质谱(GC–MS)测定卷烟主流烟气中苯并[a]芘的方法。本方法是在抽吸卷烟后,向捕集卷烟主流烟气总粒相物的滤片中加入内标物及环己烷溶液,超声提取后,萃取液用超临界流体色谱进行分离净化,切割含有苯并[a]芘的馏分再用GC–MS分析,根据目标物峰和同位素内标物峰的面积比定     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

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%).     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.