新型乘用车室内空气痕量组分快速检测系统的研制

基于自主研制的真空紫外单光子电离飞行时间质谱仪和在线高精度甲醛分析仪,研制了一套新型乘用车室内空气痕量组分的快速检测系统。通过净化空气对乘用车室内空气进行置换,置换完成后,分别利用在线挥发性有机物质谱仪和在线高精度甲醛分析仪对乘用车室内空气中痕量组分和甲醛进行连续检测。结果表明,苯、甲苯、二甲苯/乙苯、苯乙烯和甲醛在对应浓度范围内具有良好的线性,相关系数(r²)均大于0.99,相对标准偏差均小于5%,检出限分别为1.3×10^-9、0.1×10^-9、0.2×10^-9、0.8×10^-9、0.1×10^-9 mol/mol。采用该方法测定车内空气,结果显示,在短时间内,车内VOCs可快速释放达到释放亚平衡状态,并可得到亚平衡状态下的VOCs浓度及释放速率结果。测试车辆车内空气中待测物质苯、甲苯、二甲苯/乙苯、苯乙烯和甲醛的浓度分别为0.30、8.90、25.10、21.90、15.05μg/m³。该方法无复杂耗时的采样过程,操作简便,能够满足...     

气相色谱法同时测定溶剂型胶黏剂中的9种有害物质

建立了利用毛细管柱气相色谱同时测定溶剂型胶黏剂中苯、 甲苯、 对（间）二甲苯、 邻二甲苯、 二氯甲烷、1,2-二氯乙烷、1,1,2-三氯乙烷、三氯乙烯、甲苯二异氰酸酯（TDI）的方法,并对样品中有害物质的分离提取和色谱条件进行了研究.实验结果表明,方法化合物浓度在10~300 μg/mL时,线性相关系数不低于0.999 1,样品加标回收率在91.2%~104.1%之间,相对标准偏差均小于5%,检出限为0.1~3.0 μg/mL.方法不仅回收率高、重现性好,而且简便、快速.     

顶空固相微萃取-气相色谱-质谱法同时测定饮用水源水中24种VOCs

建立了同时测定饮用水源水中24种挥发性有机物(VOCs)的顶空固相微萃取-气相色谱-质谱法.用75 μm CarboxenTM-Polydimethylsiloxane(CAR-PDMS)固相微萃取柱顶空萃取水样中的VOCs,VOCs用气相色谱-质谱联用仪检测,采用内标法定量.对萃取柱涂层、样品盐度、萃取温度和萃取时间等样品前处理条件进行了优化,VOCs的检出限在0.03～0.31 μg/L之间,线性相关系数r＞0.996(二氯甲烷和三氯甲烷除外).对饮用水源水实际水样0.50μg/L和1.00 μg/L两个加标浓度水平的回收率进行了测定,三氯甲烷回收率均值分别为104％和142％,其余VOCs回收率分别为90.0％～120％和88.0％～110％,除二氯甲烷和三氯甲烷外,其余VOCs测定结果的相对标准偏差均小于15.0％(n=6).该方法适用于饮用水源水中挥发性有机物的监测分析.     

食品包装用塑料袋中残留苯系物的快速检测

利用顶空技术,采用质谱法测定,建立了一种快速测定食品包装用塑料袋中残留苯系物的质谱分析方法.苯同系物的基峰峰高与其浓度在以下范围呈线性关系0.29～29.36 μg·L-1(苯),0.29～28.87 μg·L-1(甲苯),0.29～28.67 μg·L-1(二甲苯);检出限依次为0.017,0.004,0.009 μg·L-1.回收率为91.0%～103.6%,相对标准偏差小于3.5%.     

顶空气相色谱-质谱联用法测定化妆品中α-氯甲苯

该文建立了一种适用于含苯扎氯铵的化妆品中α-氯甲苯的测定方法。首先通过气相色谱－质谱联用 法（GC－MS）剖析苯扎氯铵热分解产物的成分,确证了苯扎氯铵类化合物在气相进样口会分解产生α-氯甲苯。 采用气液平衡的顶空进样方式,并通过优化顶空进样参数、色谱分离和质谱测定条件,建立了一种化妆品中 α-氯甲苯的新型分析方法。选择顶空平衡温度和时间分别为80 ℃和30 min,样品于顶空瓶中用8 mL水和1. 0 g 氯化钠分散,以 HP－INNOWax 色谱柱（60 m × 0. 25 mm × 0. 25 μm）分离,采用选择离子监测模式（SIM）检 测,外标法定量。结果显示：α-氯甲苯在0. 01～5. 00 μg/mL质量浓度范围内与对应的峰面积呈良好的线性关 系（r = 0. 999）,方法检出限和定量下限分别为0. 02 μg/g和0. 05 μg/g,加标回收率为91. 3%～98. 8%,相对标 准偏差（RSD）为1. 5%～4. 9%。该方法操作简便,快速,灵敏度高,专一性好,能有效解决现有方法假阳性干 扰的问题,适用于各种化妆品中α-氯甲苯的准确测定。     

日本开发出检测空气中甲苯等的新试剂

日本庆应大学和神奈川技术学院最近开发出一种新试剂,这种试剂可容易地检测出室内空气中甲苯和二甲苯的浓度。 专家称,这将有助于人们及时了解室内空气污染情况,     

连续测量水中挥发性有机物的膜进样-单光子电离-质谱仪的研制及其应用

研制了膜进样-单光子电离-飞行时间质谱仪,并应用于水中挥发性有机物(VOCs)的连续在线快速测量.以50 μm硅橡胶膜为富集膜,用蠕动泵和电动切换阀,实现了水中VOCs的自动进样、富集和测量,无记忆效应.采用真空紫外灯发出的10.6 eV的光子,对待测有机物实现单光子电离,无碎片离子,便于根据分子量进行定性分析.苯、甲苯、二甲苯和氯苯等样品的响应时间均低于100 s; 苯的检出限可达3×10-9(V/V),且在10×10-9～1×10-6(V/V)范围内具有良好的线性.将仪器应用于某化工厂排污水的在线检测中,在200 s时间内可检测到20多种10×10-9(V/V)量级的有机物.结果表明: 膜进样-单光子电离-飞行时间质谱在水中VOCs在线检测方面具有广泛应用前景.     

罐采样-预浓缩/气相色谱-质谱联用测定污染源废气中118种挥发性有机物

该文采用预浓缩/气相色谱-质谱联用仪(配FID检测器)结合Dean Switch中心切割和冷柱箱技术,建立了一针进样同时测定污染源废气中118种挥发性有机物(VOCs)的分析方法。废气样品采用苏玛罐收集,稀释后进系统分析,其中C2~C3组分在FID上测定,外标法定量;其他目标物在质谱(MS)上测定,内标法定量。结果显示,118种VOCs在0.5~30 nmol/mol浓度范围内线性良好,相关系数(r2)为0.995 3~0.999 9,方法检出限为0.01~0.38 μg·m-3,定量下限为0.03~1.51 μg·m-3;在低、中、高3个加标水平下的回收率为76.4%~110%,相对标准偏差(RSD,n=7)为0.30%~6.0%。将其应用于移动污染源(叉车)及固定污染源(制鞋厂、家具厂、印刷厂、塑料厂、造船厂)废气样品中VOCs的测定,均有不同程度的检出,其中叉车尾气中总VOCs(TVOC)含量为33.50~35.25 mg·m-3,固定污染源废气中TVOC为44.54~211.71 mg·m-3。该方法简便快速、稳定灵敏、准确度高,适用于移动污染源和固定污染源废气中VOCs的定性定量分析。     

气相色谱法快速同时测定室内装饰装修材料胶黏剂中的苯、甲苯、二甲苯的含量

建立了快速、同时测定室内装饰装修材料胶黏剂中苯、甲苯、二甲苯含量的气相色谱检测法.样品用乙酸乙酯溶解处理后,用改性的聚乙二醇(FFAP)毛细管色谱柱分离,氢火焰离子化检测器检测,外标法定量.胶粘剂中苯、甲苯、二甲苯的浓度分别在8.58～171.40μg/mL、9.04～180.62μg/mL、8.80～175.92μg...     

电冷阱富集-光电离移动质谱快速检测痕量挥发性有机物

采用电动制冷机设计并搭建了一套低温富集-高温解析冷阱装置,与光电离移动质谱联用,实现了大气中痕量挥发性有机物(VOCs)快速、自动富集检测。与传统冷阱制冷方式相比,电动制冷机低温可至!196℃,体积小巧、无制冷剂消耗、便于携带。利用冷阱结合在线质谱分析了苯、甲苯和二甲苯混合气,对冷阱各参数进行了优化,结果表明:冷阱富集后苯、甲苯和二甲苯的信号强度分别提高了212、254和242倍,回收率分别达到98%、87%和85%,单样品分析时间14 min。将电冷阱结合移动式在线质谱直接分析含有39种VOCs的EPA TO-14标准混合气和室内环境空气,仪器灵敏度低于国家对室内空气中VOCs阈值。电冷阱富集在线移动式质谱可以实现大气、室内环境中痕量VOCs快速富集检测,在挥发性有机污染物现场、实时监测中具有重要的应用潜力。     

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.     

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.     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

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.     

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.