动态固相微萃取-气相色谱法测定环境空气中挥发性脂肪酸的研究

建立了动态固相微萃取-气相色谱(FID)测定环境空气中挥发性脂肪酸(VFAs)的分析方法,选择乙酸(AA)、丙酸(PA)、丁酸(BA)、异丁酸(iso-BA)、戊酸(VA)和异戊酸(iso-VA)6种代表性VFAs为研究对象,研制了动态萃取装置并建立了动态萃取机制。研究了固相微萃取材料、萃取时间、萃取温度、萃取流速、解析温度及时间对VFAs萃取效率的影响,在此基础上优化了气相色谱法检测条件。在优化条件下,6种脂肪酸的线性范围均达到4个数量级,相关系数均大于0.990。方法的检出限(S/N=3)为1.0~4.7μg/L,相对标准偏差(RSD,n=3)为1.1%~6.8%。与常规方法相比,该方法大大提高了检测范围和检测灵敏度,并成功用于环境空气中挥发性脂肪酸的分析检测。     

GC-MS分析大叶金花草中挥发性成分和脂肪酸

应用 GC-MS 联用技术对大叶金花草(Stenoloma chusana(L.)Ching)的挥发性成分和脂肪酸进行了检测,共检测出7种挥发性成分和32种脂肪酸,脂肪酸检出量为87.65%,其中饱和脂肪酸占脂肪酸总量的53.13%,不饱和脂肪酸占脂肪酸总量的46.87%.该研究为大叶金花草的进一步开发利用提供了科学依据.     

便携式GC-MS在挥发性有机物应急监测中的应用

建立了便携式GC-MS测定空气中37种挥发性有机物(VOCs)的方法,采用便携式GC-MS配置的手持探头采集大气样品,然后用便携式GC-MS进行检测.该方法能快速、有效地对空气中的37种挥发性有机物进行定性和定量,具有相关性好(r>0.995)、检出限低(0.070×10-9 ～0.94×10-9 (体积分数))、精密度好(RSD小于7.7%)、准确度高(回收率为92% ～114%)的特点,适用于大气中挥发性有机污染物的应急监测.     

热脱附-气相色谱-三重四极杆串联质谱法测定环境空气中的挥发性有机物

采用热脱附(TD)结合气相色谱-三重四极杆串联质谱(GC-MS/MS)建立了环境空气中23种挥发性有机物(VOCs)同时检测的分析方法。空气样品通过主动采样的方式富集到装有Tenax-TA填料的热脱附管中,热解吸后在选择反应监测(SRM)模式下用GC-MS/MS进行检测,内标法定量。结果表明,23种VOCs在0.01~1 ng和1~100 ng低、高两个范围内线性关系良好,相关系数(r²)均大于0.99,方法定量限为0.00008~1 μ g/m³。加标水平为2、10和50 ng时,23种VOCs的平均回收率为77%~124%。除了最低加标水平的氯苯,相对标准偏差(RSD, n=6)均小于20%。对市内3个采样点的环境空气进行测定,其中苯、甲苯、乙苯、二甲苯、苯乙烯、1,2,4-三甲基苯和六氯丁二烯均有检出。实验证明,该TD和GC-MS/MS相结合的检测方法具有准确、可靠、灵敏度高等优点,适用于环境空气中VOCs的同时测定。     

海蜇不同部位脂肪酸的组成研究

报道了黄海海域成熟海蜇不同部位脂肪酸的研究结果。利用GC-MS技术测定海蜇皮、海蜇头、海蜇生殖腺的脂肪酸组成。结果表明：海蜇含有30多种脂肪酸,3个部位的脂肪酸组成差别不大;海蜇中含有丰富的多不饱和脂肪酸,含量在36．2％～38．7％之间,其中二十二碳六烯酸(DHA)、二十碳四烯酸(AA)和二十碳五烯酸(EPA)含量较高。     

HS/GC-MS法对卷烟包装材料中挥发性有机化合物的检测

建立了一种用于测定卷烟包装材料中挥发性有机物(VOCs)的分析方法.采用三醋酸甘油酯为基质,利用顶空技术对样品进行前处理,并与气相色谱质谱(GC-MS)联用,用离子选择对17种挥发性有机物进行了定量分析.在优化的实验条件下,方法线性关系良好,17种挥发性有机物的相关系数均大于0.999,检出限为0.30 ～18 μg/m2,比全扫描的检出限低1 ～3个数量级.17种挥发性有机物的回收率为90% ～101%,相对标准偏差小于3.67%.该法简便、快速、重复性好、定性定量准确,适于大批卷烟包装材料中挥发性有机化合物的检测.     

烟叶中26种挥发性与半挥发性有机酸的GC-MS/SIM法同时分析

采用加速溶剂萃取,以二氯甲烷-乙腈(体积比1 : 2)为萃取溶剂,N,O-双(三甲基硅基)三氟乙酰胺硅烷化,反-2-己烯酸和肉桂酸为内标,GC-MS/SIM法同时测定了烟叶中的甲酸、乙酸、乳酸、苯甲酸、十六酸、十八酸等26种挥发性、半挥发性有机酸.方法的回收率为81% ～106%,相对标准偏差为1.73% ～7.08%,检出限为0.1 ～13.72 μg/g.以该方法对部分烟叶样品中挥发性、半挥发性有机酸进行了定量分析.     

烟草中挥发性和非挥发性有机酸的快速测定

建立了气相色谱-质谱(GC-MS)法快速测定烟草中22种非挥发性、挥发性有机酸的分析方法。采用对甲苯磺酸-硫酸-甲醇(PTSA/H2SO4/CH3OH)酯化试剂对烟草样品进行一次酯化,生成的有机酸酯用GC-MS进行分析。结果表明,酯化时间从20 h缩短到1 h,非挥发酸回收率在93.4%~103.2%之间,相对标准偏差(RSD)小于4.2%;挥发性有机酸回收率在89.2%~99.1%之间,RSD小于3.5%。该方法具有简便、快速,结果准确等特点,用于测定部分烟草样品的挥发性、非挥发性有机酸,取得了满意的结果。     

便携式气相色谱-质谱仪测定空气中挥发性有机污染物的准确性

便携式气相色谱-质谱仪(便携式GC-MS)能同时对多组分复杂有机物进行定性定量分析,在环境监测尤其是事故现场应急监测中发挥越来越重要的作用。本文比较了便携式GC-MS与EPATO-14A方法分析测定环境空气中低浓度挥发性有机物(VOCs)的性能,并探讨了利用定量环(loop环)模式测定高浓度VOCs的准确度。结果表明,采用内标标准曲线定量,HAPSITE便携式GC-MS测定空气中VOCs的检出限与EPATO-14A方法相当,准确度和精密度略低,但均符合环境监测分析的要求。利用loop环可对大部分10-6级的高浓度VOCs样品进行较为准确的测定,在突发性环境污染事故中可以得到基本准确的结果。     

顶空气相色谱-质谱联用法分析粪便中挥发性脂肪酸

建立了一种快速分析粪便中挥发性脂肪酸(Volatile fatty acids,VFAs)的顶空气相色谱-质谱联用法(Headspace gas chromatography-mass spectrometry,HS-GC/MS)。粪便样品用6%H3PO4溶液按1∶2(m/V)混悬后密封于顶空进样瓶中,直接进行HS-GC/MS检测。顶空振荡室加热温度为80℃,振荡加热时间30 min,顶空进样针温度为80℃,不分流进样1 mL;采用DB-FFAP毛细管柱(30 m×0.25 mm×0.25μm),进样口温度为250℃,升温程序(初始温度50℃保持1 min,以10℃/min升至200℃),载气(高纯氦)流速为1.0 mL/min;使用电子轰击(Electron impact,EI)离子源,电子能量为-70 eV,离子源温度为250℃,传输线温度为280℃,电子倍增器电压为0.95 kV,全扫描模式,扫描范围m/z 33~200。结果表明,本方法能够应用于人及大鼠粪便中挥发性脂肪酸的分析,通过NIST标准谱库检索,采用对照品比对以及质谱数据解析的方法,在人的粪便样品中检测到9种挥发性脂肪酸:乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、异己酸、己酸、庚酸;在大鼠粪便中检测到8种挥发性脂肪酸:乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、己酸、庚酸。通过峰面积归一化法,计算得到乙酸、丙酸、丁酸的相对百分含量约占挥发性脂肪酸总量的85%。本方法简单、灵敏,可用于人和大鼠粪便中挥发性脂肪酸的快速检测。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.