微波消解-微波等离子体炬原子发射光谱测定啤酒中的铜、锌、铁、锰、硒、锶

建立了微波消解-微波等离子体炬原子发射光谱(MPT-AES)法测定啤酒中微量元素。考察了微波前向功率、工作气流量、载气流量等参数,确定了MPT-AES法测定各元素的最佳实验条件。在该条件下铜、锌、铁、锰、硒、锶的检出限分别为7ng.mL-1、46ng.mL-1、13ng.mL-1、8ng.mL-1、1.2ng.mL-1、5.6ng.mL-1。相对标准偏差(RSD)均在0.9%～4.8%之间,线性范围分别为0.1～100μg.mL-1、0.5～100μg.mL-1、0.5～100μg.mL-1、0.1～100μg.mL-1、0.01～10μg.mL-1、0.05～100μg.mL-1,加标回收率均在96%～110%之间。     

二苯氨基脲-乳化剂OP分光光度法测定钢中微量钒

测定钒的胶束增溶分光光度法绝大多数是阳离子表面活性剂体系,非离子表面活性剂体系则很少被研究。本文研究了在非离子表面活性剂乳化剂OP存在下,二苯氨基脲(DPC)和钒的显色反应和光度特性,拟定了用该体系测定微量钒的条件和方法。试验表明,络合物最大吸收位于544 nm处,0—30μg/50mL钒符合比尔定律,摩尔吸光系数为7.6×10~4,络合物组成比为V:DPC=1:2,室温下5min显色完全.     

Al~(3+)-核固红-蛋白质体系的光谱特性及其分析应用

在pH为4.0时,Al3+与核固红形成的螯合物能够通过静电作用力和疏水作用力在蛋白质表面聚集形成聚集体。据此,提出了共振瑞利散射光谱法测定蛋白质的新方法。研究了体系的吸收光谱、荧光光谱及共振散射光谱。采用共振光散射技术测定了金属螯合物的组成。探讨了反应机理和共振光散射增强的主要原因。在440 nm处,人血清白蛋白(HSA)和牛血清白蛋白(BSA)的线性范围分别是0.2~12.0μg·mL-1和0.6~26.0μg·mL-1,对应的检测限分别是19.9 ng·mL-1和40.9 ng·mL-1。在584 nm处HSA和BSA的线性范围分别是0.05~6.0μg·mL-1和0.2~14.0μg·mL-1,检测限分别是11.5 ng·mL-1和23.3 ng·mL-1。方法可用于人血清、唾液和尿样中蛋白质含量的测定。将该方法的测定结果与考马斯亮蓝法的测定结果进行对照,经t-检验证明两种方法无显著性差异。     

OP存在下钼—芦丁—CPC三元配合物光度法测定芦丁研究

本文详细研究了在乙酸-乙酸钠缓中溶液中,钼-芦丁-CPC三元配合物体系的显色反应条件和吸光光度特性,非离子表面活性剂OP对该体系具有胶束增溶作用.拟定了测定芦丁的方法.该方法的检测波长为430nm,摩尔吸光系数E_(430)4.1×10~4检出限和线性范围分别为0.02μg·ml~(-1)和0～25μg·ml~(-1).     

吐温-80增敏MPT-AES测定煤焦油中铜

研究了在非离子表面活性剂吐温-80增敏作用下微波等离子体炬原子发射光谱法(MPT-AES)测定煤焦油中铜的方法。实验结果表明,非离子表面活性剂吐温-80对铜发射强度具有明显的增敏作用。在分析谱线324.754nm,微波功率90W,载气流量1100mL.min-1,工作气流量470 mL.min-1,吐温-80的质量分数为0.8%条件下,绘制铜的工作曲线,得到铜的线性范围为0～8μg.mL-1,铜的检出限为2.1ng.mL-1,方法的精密度为0.81%;而未加吐温-80时铜的检出限为5.8ng.mL-1,方法的精密度为1.22%。对常见的共存元素影响进行考察,20倍的Mn、Zn、15倍的Mg、Na,10倍的V、Ni,5倍的Fe、Ca均对铜测定无影响。煤焦油中铜测定结果的相对标准偏差不大于4.7%,加标回收实验的回收率在95.6%～104.0%。     

虎红-牛血清白蛋白共振光散射光谱研究及其分析应用

基于在pH3.0的BR缓冲溶液中蛋白质的加入使虎红的共振光散射信号增强,建立了一种蛋白质测定的新方法.详细地探讨了pH、染料用量、表面活性剂、离子强度、共存物质等对信号的影响.牛血清白蛋白浓度在0～4.0μg/mL范围内与体系散射强度呈线性关系,检出限为0.01718μg/mL.该方法用于合成样品中牛血清白蛋白的测定,...     

刚果红-OP-蛋白质体系共振光散射特性的研究及牛尿中白蛋白的测定

蛋白质的测定对于生命科学的研究、临床诊断和疾病的治疗均有十分重要的意义~([1]).本文研究了刚果红(Congo Red,CR)与牛血清白蛋白的相互作用.实验表明:在非离子表面活性剂聚乙二醇辛基苯基醚(乳化剂OP)的存在下及pH=4.35的B-R缓冲介质中,蛋白质与刚果红形成复合物,使573 nm处的共振散射光谱得到加强,并且增强的共振光散射信号与蛋白质的浓度成正比.据此,建立了共振光散射技术测定微量蛋白质的新方法.     

偶氮胂-DBS用于光度法测定牛血清白蛋白

在室温下,于pH 2.5的Britton-Robinson缓冲溶液中及非离子表面活性剂OP存在下,牛血清白蛋白(BSA)与偶氮胂-DBS的复合物的最大吸收在514 nm波长处,但显色复合物与试剂空白吸光度之差在370 nm处最大,选择在370 nm处测定,反应迅速完成。非离子表面活性剂OP可提高反应灵敏度及复合物稳定性。乙醇可提高体系灵敏度。BSA的质量范围在0~60.0 mg.L-1范围内符合比耳定律,方法表观摩尔吸光率3ε70 nm=8.58×105L.mol-1.cm-1。方法用于测定血清样品中蛋白质的总量,5次测定值的RSD为0.60%,回收率为98.0%。     

反相流动注射催化光度法测定痕量钒的研究

基于在非离子表面活性剂OP存在下,以柠檬酸作活化剂,V(v)对溴酸钠氧化罗丹明B褪色的催化作用,建立了痕量钒的反相流动注射分析(r-FIA)新方法。方法的线性范围为10～200μg·L~(-1),检出限为1.9μg·L~(-1),对40μg·L~(-1)钒平行测定11次的相对标准偏差为1.5％,进样频率为16次·h~(-1)。方法应用于各种水样中痕量钒的测定,并进行回收试验,回收率为90％～104％。     

PbS-PAA复合纳米粒子共振光散射法测定蛋白质

基于蛋白质对聚丙烯酸修饰的纳米PbS复合粒子共振光散射的增强效应,建立了一种新的测定蛋白质的共振光散射法。在超声辐射下,用过二硫酸钾(KPS)做引发剂,用原位聚合的方法使丙烯酸原位聚合在纳米PbS上。所得的复合纳米粒子表面就覆盖了大量的羧基(—COOH),不仅增加了复合纳米粒子的水溶性和稳定性,而且使其具有良好的生物相容性。在pH=0.91的NaAc-HCl溶液中,复合纳米粒子与蛋白质结合后,使得其共振光散射强度剧增,且其增强的程度与所加入的蛋白质浓度成线性关系。在λ=385 nm处,共振光散射强度最大。在最佳条件下,建立了工作曲线,线性范围为0.2~20μg.mL-1(HSA),0.2~20μg.mL-1(Humanγ_IgG),0.15~18μg.mL-1(BSA);检出限分别为25、14、27 ng.mL-1。该法简便、快速、灵敏度高。     

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.