顶空-气相色谱法测定水中7种苯系物

建立顶空-毛细柱气相色谱法测定水中苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯和苯乙烯7种苯系物的方法。对色谱条件及顶空条件进行了优化,采用自动顶空进样方式,经70℃平衡30 min,用Rtx-Wax毛细管柱分离,使用火焰离子化检测器检测。7种苯系物的质量浓度在10～100μg/L范围内与其对应的色谱峰面积呈线性关系,相关系数在0.999 0～0.999 6之间,方法检出限为0.2～0.9μg/L,7种苯系物的回收率为96.5%～106.5%,测定结果的相对标准偏差为1.0%～2.2%(n=6)。该方法操作简单,重现性好,测定结果准确可靠,检出限满足国家标准要求,可用于水中7种苯系物的检测分析。     

自动顶空毛细管气相色谱法测定水中8种苯系物

建立自动顶空-毛细管气相色谱同时测定水中8种苯系物的方法.采用stabilwax-DA色谱柱,对平衡温度、平衡时间等顶空条件进行了优化,并对水中苯系物进行测定.8种苯系物平均加标回收率为93.3%～115.0%,检出限为1.2～2.0 μg/L,测定结果的相对标准偏差为1.8%～7.3%(n=6).该法操作简单、灵敏度高、重现性好,可以满足饮用水中苯系物的测定.     

顶空-气相色谱法同时测定饮用水中八种挥发性苯系物

利用顶空-毛细管柱气相色谱技术对饮用水中的苯、甲苯、乙苯、邻二甲笨、对二甲笨、间二甲笨、异丙苯、苯乙烯的测定方法进行了研究,并对平衡时间、气／液体积比、水中含盐量等影响测定因素进行了探讨,对色谱条件和顶空进样条件进行了优化。该方法选用HP-INNOWAX色谱柱,使一直较难分离的间、对二甲苯得到了很好的分离。对八种苯系物进行了最低检出限、线性、回收率、精密度试验,其平均回收率为97．4％～1063％（n=7）,相对标准偏差为2．55％～3．83％（n=7）,最低检出限为0．06～0．10μg／L。测定结果表明,该法操作简单,重现性好,灵敏度高,完全可以满足饮用水中挥发性苯系物的测定。     

气相色谱法测定修正液中11种苯系物

建立了气相色谱测定修正液中11种苯系物的方法.通过对样品前处理方法的考察及色谱条件的优化,确定采用乙酸乙酯作为溶剂对样品进行提取,提取液经离心、过滤后由气相色谱法测定,外标法定量.11种苯系物在1.0～200.0 mg/L质量浓度范围内呈良好线性,相关系数(r2)为0.999 2～0.999 9,检出限(LOD)均为1.0 mg/kg,加标回收率为90％ ～ 105％,相对标准偏差(RSD,n=6)均小于6％.该方法简便,快速,结果准确可靠.     

纳米复合材料催化发光法测定空气中的苯系物

基于苯系物在纳米材料上的催化发光现象，建立了一种快速测定空气中苯系物的方法。在铜锰铁复合纳米材料上的最佳测定条件为：检测波长460nm，表面温度320℃，气体流速120mL/min。方法的检出限（3σ）为0．5mg／m^3，线性范围为1～80mg／m^3，相关系数为0．9995。对常见共存物的研究表明，方法有较好的选择性。     

顶空气相色谱法同时测定饮用水中苯系物和溴代苯、对氟溴苯

建立顶空气相色谱同时测定水中8种苯系物和溴代苯、对氟溴苯的方法。水样经气液平衡后,用Sepelco Wax 10色谱柱分离,气相色谱FID检测器进行分析。在所建立的最佳实验条件下,苯系物和溴代苯、对氟溴苯得到有效分离。苯系物和溴代苯、对氟溴苯的色谱峰面积分别与其质量浓度呈良好的线性关系,线性相关系数不小于0.999 7。方法的检出限为0.94~2.36μg/L,测定结果的相对标准偏差为1.4%~5.7%(n=6),加标回收率为90.8%~99.1%。该方法灵敏度高,操作简便,干扰少,适用于生活饮用水中8种苯系物和溴代苯、对氟溴苯的同时分析。     

离子色谱法测定水样中的氯化物

建立离子色谱法测定水样中氯化物的方法,Cl^-浓度在0．40～4．00mg／L范围内与色谱峰面积呈线性关系,线性方程为A=0．0680c＋0．0011,线性相关系数r=0．9995。样品6次测定结果的相对标准偏差为1．01％,加标回收率为91．8％～97．3％。与硝酸银滴定法进行比对试验,两种方法测定结果基本一致。离子色谱法操作方便快捷,污染少,测定结果准确、可靠。     

固相微萃取-高效液相色谱联用测定水样中的痕量苯并(k)荧蒽

研究了固相微萃取(SPME)-高效液相色谱(HPLC)联用测定水样中痕量苯并(k)荧蒽的的分析方法。对SPME的条件如萃取时间、萃取温度、离子强度、解吸方式、解吸溶剂、解吸时间和HPLC条件进行了优化，建立了SPME-HPLC联用分析水样中痕量苯并(k)荧蒽的方法，并用于自来水、雨水和纯净水等实际水样的分析。SPME优化的条件为室温、搅拌速度1100r／min、萃取时间30min、甲醇解吸溶剂、解吸时间2min。HPLC的条件为C18反相色谱柱、甲醇流动相、流速1mL/min、紫外检测器、波长244nm，以峰高为测量信号。方法的线性范围为0～8．00μg／L，检出限为0．014μg／L，相对标准偏差(n=6)为6．7％，回收率为82．0％～104．2％。该方法适合于水样中痕量苯并(k)荧蒽的分析。     

顶空固相微萃取-气相色谱法测定环保水性涂料中的挥发性有机物

建立了一种固相微萃取．气相色谱同时测定环保水性涂料中的苯系物和卤代烃的方法。选择涂层厚度为70μm的聚乙二醇-二乙烯苯(CW-DVB)萃取纤维,对固相微萃取的萃取条件进行了优化。该法相对标准偏差小于10％,样品的加标回收率大于72．2％,已成功地测定了11种水性涂料中的苯系物和卤代烷。     

海水中痕量苯系物的吹扫捕集/气相色谱质谱联用测定

建立了海水中苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯以及苯乙烯7种苯系物的测定方法。采用吹扫捕集法对海水中的苯系物进行富集,热解吸后导入气相色谱-质谱仪,并选用选择离子模式(SIM)进行检测。结果表明:在100.0～2 000.0 ng/L范围内7种苯系物浓度与仪器响应值的线性关系良好,相关系数为0.999 6～0.999 8,方法检出限为5.9～10.7 ng/L;两种不同浓度加标水平(250.0、1000.0 ng/L)的平均回收率分别为84%～105%和96%～97%,相对标准偏差(n=6)分别为3.7%～6.5%和2.1%～3.3%。该方法准确、快速,且具有富集效率高、无试剂再污染等优点,适用于海水中痕量苯系物的分析测定。     

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.