顶空固相微萃取-气相色谱法测定饮用水中氯酚

提出了应用气相色谱法与顶空固相微萃取样品预处理技术相结合的方法测定饮用水中2,4,6-三氯酚(TCP)和五氯酚(PCP)。选用20mL顶空瓶,其中预置0.1mol·L~(-1)盐酸溶液0.5mL及氯化钠4.0g,加入水样10.0mL,立即封盖。插入85μm聚丙烯酸酯萃取头,在500r·min~(-1)转速振荡条件下于60℃萃取40 min,随之进入色谱仪解吸并测定。测定中采用HP-5毛细管柱和程序升温(40℃～280℃)条件,并用载气流量为3mL·min~(-1)。测得2,4,6-TCP及PCP的线性范围依次为55μg·L~(-1)和12μg·L~(-1)以内,其检出限(3S/N)依次为0.15μg·L~(-1)和0.13μg·L~(-1),加入3个浓度水平的标准溶液对方法的回收率及精密度作了试验,测得回收率在90.0%～112.8%之间,相对标准偏差(n=6)在3.0%～4.9%之间。     

顶空固相微萃取-气相色谱法测定辣椒根系分泌物中邻苯二甲酸酯类化合物

用顶空固相微萃取法提取样品中5种邻苯二甲酸酯类化合物(PAEs),用气相色谱法测定其含量。移取水栽培法培育辣椒的营养液10mL,置于顶空瓶中,进行固相微萃取到达要求的时间后,将萃取头迅速插入色谱仪进样口进行解吸。选用65μm PDMS/DVB纤维头作为微萃取头,并在下述条件下进行固相微萃取:①萃取时间及温度:50min,80℃;②样品体积:10mL;③搅拌速率:1 000r·min-1;④样品溶液的离子强度:氯化钠加入量达18%;⑤溶液的酸度:近中性,样品溶液的原始酸度(pH 6.5~7.2)正符合此要求;⑥解吸温度和时间:250℃,10min。结果表明:5种PAEs的线性范围均在0.2~10mg·L-1之间,检出限(3S/N)均小于0.12mg·L-1。方法的回收率在83.4%~105%之间,测定值的相对标准偏差(n=5)均小于9%。     

顶空固相微萃取-气相色谱法测定植物蛋白饮料中的苯甲醛

采用顶空固相微萃取-气相色谱法(HS-SPME-GC)测定植物蛋白饮料中的苯甲醛。10mL顶空瓶中加入样品5.00mL和氯化钠1.50g,40℃下平衡20min,然后采用聚二甲基硅氧烷-二乙烯基苯(PDMS-DVB)萃取探头萃取顶空气体50 min后,在气相色谱仪上于250℃解析1.0min,采用RTX-5色谱柱分离,以氢火焰离子化检测器(FID)进行检测。苯甲醛的质量浓度在10.00~500.0μg·L-1范围内与其色谱峰面积呈线性关系,回收率为92.6%,相对标准偏差为1.4%。方法应用于市售植物蛋白饮料中苯甲醛的测定。     

顶空固相微萃取气相色谱法测定浓海水中的氯酚

建立浓海水中氯酚的顶空固相微萃取气相色谱法检测方法。采用顶空固相微萃取对海水淡化排放的浓海水样品中2,4,6-三氯酚(2,4,6-TCP)和五氯酚(PCP)进行分离富集,气相色谱-电子捕获检测器(μECD)测定浓海水样品中2,4,6-TCP和PCP的含量。讨论了萃取时间、萃取温度、水样盐度等实验条件对富集效率的影响,确定了萃取时间为40 min,萃取温度为60℃。2,4,6-TCP,PCP的质量浓度在0.500~20.0μg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数均大于0.999,2,4,6-TCP和PCP的检出限(2S/N)分别为0.055,0.128μg/L,测定结果的相对标准偏差为3.65%~11.4%(n=6),加标回收率为73.5%~119.0%。该方法快速,灵敏度高,适合于浓海水中氯酚的分析。     

顶空固相微萃取-气相色谱法测定匹伐他汀钙原料药中6种溶剂残留北大核心CSCD

将样品用N,N-二甲基甲酰胺溶解配制成100g·L-1的样品溶液,取样品溶液10mL置于顶空瓶中,于40℃水浴加热5min后,进行固相微萃取,采用聚二甲基硅氧烷萃取头,萃取温度为40℃,吸附时间和脱附时间分别为30,10s。甲醇、四氢呋喃、乙酸乙酯、乙醇、乙腈、甲苯在SE-54毛细管色谱柱上分离,采用火焰离子化检测器。上述6种溶剂的峰面积与其质量浓度在一定范围内呈线性关系,检出限(3S/N)在1.0~2.3mg·L-1之间。加标回收率在95.8%~104%之间,测定值的相对标准偏差(n=8)小于9.0%。     

顶空固相微萃取-气相色谱法测定匹伐他汀钙原料药中6种溶剂残留

将样品用N,N-二甲基甲酰胺溶解配制成100g·L-1的样品溶液,取样品溶液10mL置于顶空瓶中,于40℃水浴加热5min后,进行固相微萃取,采用聚二甲基硅氧烷萃取头,萃取温度为40℃,吸附时间和脱附时间分别为30,10s。甲醇、四氢呋喃、乙酸乙酯、乙醇、乙腈、甲苯在SE-54毛细管色谱柱上分离,采用火焰离子化检测器。上述6种溶剂的峰面积与其质量浓度在一定范围内呈线性关系,检出限(3S/N)在1.0~2.3mg·L-1之间。加标回收率在95.8%~104%之间,测定值的相对标准偏差(n=8)小于9.0%。     

固相微萃取-气相色谱-质谱法测定饮用水源中53种挥发性有机污染物

应用固相微萃取-气相色谱-质谱法测定饮用水源中53种挥发性有机污染物的含量。优化的试验条件如下:1萃取纤维为DVB/CAR/PDMS;2萃取温度为25℃;3顶空体积为9mL;4萃取时间为10min;5解吸温度为200℃;6解吸时间为3min。在气相色谱分离中用VF-624MS柱为固定相,在质谱分析中采用全扫描模式。53种挥发性有机污染物在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.001~0.130μg·L-1之间。方法用于实际水样的分析,加标回收率在75.9%~107%之间,测定值的相对标准偏差(n=5)在0.5%~18%之间。     

顶空固相微萃取-气相色谱法测定水中四乙基铅

提出了顶空固相微萃取-气相色谱法测定水中四乙基铅含量的方法。为使固相微萃取达到更高的效率,选用聚二甲基硅氧烷填料(PDMS)作为微萃取的涂层,萃取温度及时间为60℃和30min。用DB-5色谱柱分离,用电子捕获检测器检测。四乙基铅的质量浓度在0.05～20.0μg·L-1范围内与峰面积呈线性关系,方法的检出限(3S/N)为0.02μg·L-1。以水样为基体,在3种浓度水平下进行加标回收试验,回收率在87.0%～90.1%之间,测定值的相对标准偏差(n=7)在3.7%～4.2%之间。     

静态顶空-气相色谱法测定养殖用水中11种氯苯类化合物

提出了静态顶空-气相色谱法测定养殖用水中11种氯苯类化合物的方法。取10mL含200g·L-1氯化钠的水样在20mL顶空瓶中于70℃振摇30min进行顶空进样的条件优化。选用DB-35MS毛细管气相色谱柱(30m×0.25mm,0.25μm)分离,电子捕获检测器检测,外标法或标准加入法定量。在优化条件下,二氯苯、三氯苯、四氯苯的线性范围分别为0.16~8μg·L-1,0.017 6~0.88μg·L-1,0.004~0.2μg·L-1,五氯苯和六氯苯的线性范围均为0.001~0.05μg·L-1。11种氯苯类化合物检出限(3S/N)为0.0002~0.04μg·L-1,应用此方法对养殖用水进行测定,回收率在86.0%~106%之间,测定值的相对标准偏差(n=5)在2.1%~5.8%之间。     

顶空-箭形固相微萃取-气相色谱-质谱法测定水中松节油的含量北大核心CSCD

在顶空瓶中加入水样10.0 mL、氯化钠3 g和20.0 mg·L^(-1)内标溶液10.0μL,选择涂层为120μm二乙烯苯/聚二甲基硅氧烷的箭形固相微萃取头,于50℃萃取30 min,脱附的气体用DB-1毛细管色谱柱分离,质谱仪检测,内标法定量。结果显示:松节油的主要成分为α-蒎烯,还有少量莰烯、β-蒎烯和柠檬烯等;松节油标准曲线的线性范围为5.0~100.0μg·L^(-1),检出限(3.143s)为0.6μg·L^(-1);对空白样品进行加标回收试验,回收率为95.9%~98.0%,测定值的相对标准偏差(n=6)为3.7%~4.3%;方法用于实际样品分析,结果均未检出松节油。     

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.