毛细管气相色谱法测定5种中草药中有机氯农药的残留量

建立了怀牛夕等 5种中草药中六六六及滴滴涕异构体含量的气相色谱分析方法。样品以石油醚 +丙酮在索氏提取器中提取 ,提取液以浓硫酸净化。采用SE 30弹性石英毛细管柱分离样品 ,GC ECD检测六六六、滴滴涕农药的残留量。方法的线性范围为 5 .7× 10 - 7～ 2 .8× 10 - 4μg ;最小检测量为 1.3× 10 - 1 4～ 2 .5×10 - 1 2 g ;加样平均回收率为 88.8%～ 99.1% ;RSD为 0 .9%～ 5 .3%。     

烟草中菊酯类农药残留量及其捕集转移率的测定

建立了一种同时测定烟草中5种拟除虫菊酯农药残留量及其捕集转移率的毛细管气相色谱法 ;样品经丙酮提取 ,石油醚萃取 ,硅酸镁载体净化 ,GC -ECD(63Ni)检测 ,外标法定量 ;实验表明 ,加标0.01×10-6～1.0×10-6 含量水平的功夫菊酯和溴氰菊酯 ,回收率为90%～96 % ,加标0.2×10-6～20×10-6 含量水平的甲氰菊酯、氯氰菊酯和氰戊菊酯 ,回收率为92 %～102 % ;同一样品中10次测定这5种菊酯类农药残留量的相对标准偏差为4.4 %～13%。     

流动注射安培法快速测定食盐中碘

报道了在酸性溶液中 ,IO- 3可被过量的I- 还原 ,FI流动注射安培法快速测定食盐中碘的方法。溶解于蒸馏水中的食盐样品 (30 μl)注入pH 1的 0 .1mol·L- 1NaCl + 1× 10 - 3mol·L- 1KI的载液中。自行研制的壁喷玻碳电极安培流通检测池作为工作电极 ,电位为 + 0 .2V(vs.SCE)。该系统和反向 (注入KI)系统的线性范围均为 1× 10 - 6 ～ 1× 10 - 4mol·L- 1,检出限为 5× 10 - 7mol·L- 1,相对标准偏差为 0 .8% (n =37) ,样品测定的回收率为 97.6 %～ 10 4 % ,采样频率 90样·h- 1。通过Bernoull恒流瓶可获得无脉冲载流。     

微渗析-液相色谱电化学检测法测定全血中的半胱氨酸和谷胱甘肽

采用微渗析取样作为样品预处理技术,与高效液相色谱电化学检测联用,建立了一种测定血中半胱氨酸(Cys)和谷胱甘肽(GSH)的新方法。电化学检测以玻碳电极为工作电极,结果表明在3.5×10-6～1.0×10-3mol/L浓度范围内,Cys和GSH的浓度分别与氧化峰的峰电流呈良好的线性关系,线性相关系数分别为0.9971和0.9982,检测限分别为1.2×10-6mol/L和3.2×10-6mol/L。     

蜂蜜中咖啡因含量的液相色谱法测定

介绍了用液相色谱法测定蜂蜜中咖啡因含量 ,样品在碱性条件下经氯仿萃取 ,萃取液用HPLC进行检测 ,其线性范围在0.010×10 -6～10×10 -6(w) ,定量下限为0.010×10 -6(w) ,回收率>80% ,相对标准偏差<2%。     

几种常见阴离子的高效毛细管电泳-电导分离检测

采用柠檬酸-柠檬酸钠作为缓冲体系,使用负高压,对Cl-、NO3-、HCO3-、H2PO4-几种常见阴离子进行了分离检测,研究了缓冲剂的种类、浓度、pH值及操作电压对分离的影响;在选定的条件下,定量线性范围为Cl-5.0×10-5～2.5×103md/L,NO3-6.0×10-5～2.0×10-3mol/L,HCO3-1.0×10-5～2.0×10-3mol/L,H2PO4-6.0×10-5～1.0×10-3mol/L;检出限为Cl-1.5×10-5mol/L,NO3-3.0×10-5mol/L,HCO3-1.0×10mol/L,H2PO4-2.0×10-5mol/L;4种离子的RSD(n=6)分别为3.1%、33%、2.6%和2.9%;应用选定条件对自来水样品进行了分析,结果令人满意.     

基于水溶性共轭聚合物荧光增强测定精氨酸

在水溶液中,精氨酸(Arg)能使水溶性共轭聚合物P1的荧光高灵敏、特异性地增强,从而建立了一种免标记的荧光增强型Arg检测新方法.该方法Arg检测的线性范围为6.0×10-8～3.06×10-6 mol/L和3.06×10-6～7.11×10-5 mol/L;检出限为2.0×10-8 mol/L.方法简单、快捷、选择性好、灵敏度高,可用于盐酸精氨酸注射液样品的检测.     

氮杂芳烃的高效液相色谱分析

本文报导了用硅胶吸附型填料(Partisil-PXS)以正己烷/异丙醇(98/2)为流动相,用带有紫外检测器的高效液相色谱(HPLC)分离11种氮杂芳烃的方法。应用此法测定了焦炉大气颗粒物中存在的4种氮杂芳烃,在60～300ng范围内浓度与检测器响应值成线性关系。定量重现性好,对标准样品的变异系数在±5%以内,对环境样品的变异系数为±10%。使用紫外检测器对氮杂芳烃检测限为1×10~(-9)克。荧光检测器对氮杂芳烃的检测限为1×10~(-9)～1×10~(-10)克。     

纯铝中微量钴镍的极谱测定

钴、镍在丁二酮肟 氯化铵 氨 亚硝酸钠体系中能产生极其灵敏的极谱催化波。镍峰电位为 - 0 .98V ,钴峰电位为 - 1.18V(vs .SCE)。钴、镍的线性范围分别为 1.2× 10 -4 ～ 6.0× 10 -2 μg·ml-1,2 .0× 10 -3～ 2 .0× 10 -1μg·ml-1,检出限分别为 3× 10 -11% ,3.3× 10 -10 %。用于测定纯铝样品中微量的钴、镍 ,重现性好 ,结果满意     

毛细管电泳电化学检测法测定胡黄连中香草酸和阿魏酸的含量

采用毛细管电泳电化学检测法测定了胡黄连中香草酸和阿魏酸的含量 ;研究了电极电位、运行缓冲液的浓度和酸度、电泳电压及进样时间等对电泳的影响 ,得到了最优化的测定条件 ;以直径为300μm的碳圆盘电极为检测电极 ,工作电极电位为0.8V(vs.SCE) ,在50mmol/L硼砂(pH8.4)运行缓冲液中 ,上述两组分在8min内完全分离 ;香草酸和阿魏酸线性范围分别为5×10-4～1×10-6 mol/L和1×10-3～1×10-6 mol/L ,检出限分别为4.2×10 -7和3.0×10 -7mol/L ;7次平行进样的相对标准偏差(RSD)为2.2 %和2.8 % ,回收率(n=3)分别为99%和103 % ,该法灵敏可靠 ,结果令人满意。     

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.