高压釜消解-氢化物发生原子荧光光度法测定土壤中的砷、硒

对高压釜密封消解一氢化物发生原子荧光法测定土壤中砷、硒的方法进行了研究。采用HNO3-HClO4作消解剂，在最佳的消解条件和测定条件下，测定砷、硒的线性回归方程分别为I=244．1c 1．03、I=88．26c 2．86．线性范围均为0．50～10．00μg／L，相关系数均为0．9999，检出限均为0．0002μg/mL。测定土壤中砷、硒的回收率分别为90％～105％、89％～104％，RSD分别为2．2％～4．0％、1．9％～3．1％。     

人血清白蛋白共振RayIeigh光散射检测氟离子

通过研究F^-离子对人血清白蛋白(HSA)溶液共振Rayleigh光散射(RLS)的增强效应,建立一种基于生物蛋白RLS增强测定环境中氟离子的新型检测方法。实验条件为λex=λem=368nm,pH=5．80,t=32℃。结果表明,应用含氟离子溶液与空白溶液在368nm处RLS差值(△／),标准曲线法测定样品中的氟离子,方法线性范围为4．78～16．2μg／mL,r=0．992,检出限为1．43μg／mL。方法精密度(RSD为1．31％～5．72％)和准确度(回收率R为91％～109％)较好。     

微波消解-氢化物发生原子荧光法测定塑料原料及其制品中的砷、汞

采用微波消解进行样品前处理，以硫脲为预还原剂，用氢化物发生原子荧光法测定塑料原料及其制品中的砷、汞。测定砷和汞的线性范围均为0～8μg／L，砷、汞的检出限分别为0．005、0．076μg／L，测定结果的相对标准偏差分别为4.96％～7．38％、2．94％～7．20％(n=6)，回收率分别为92．0％～103．2％、92．0％～98.0％。     

碲化镉纳米晶荧光猝灭法测定痕量铜(Ⅱ)

制备了水溶性的CdTe纳米晶。基于铜（Ⅱ）离子在pH=7,80的磷酸盐缓冲溶液中对该纳米晶的荧光具有较强的猝灭作用,建立了一种测定铜（Ⅱ）离子的新方法。在最佳条件下,体系的相对荧光强度（△F）与铜（Ⅱ）离子的浓度呈线性关系,线性范围为8．0～320．0μg／L,其线性回归方程为：△F=-8．18-0．14c（μg／L）;检出限为3．24μg／L。本方法用于实际样品中痕量铜的测定,结果令人满意。     

碱性品红共振光散射法测定DNA研究

基于脱氧核糖核酸（DNA）对有机染料碱性品红的共振光散射增强效应，拟订了一种测定DNA的共振光散射法。在pH=6．75～7．25的范围内，碱性品红在594nm处的共振光散射增强与yDNA和ctDNA的浓度呈线性关系，线性范围分别为0．20～1．60μg／mL和0～1．50μg／mL，相关系数分别为0．9997和0．9994，检出限可达26．5μg／L。该方法简便、快速，用于合成样品中DNA的测定，结果满意。     

方波伏安法间接测定饲料中的高含量磷

在pH=5．5的六次甲基四胺-盐酸缓冲溶液中，硝酸铅与磷酸根和氯离子反应，生成磷酸氯化铅复盐沉淀，用方波伏安法测定过量的铅离子，从而间接测定无机磷。在最佳测定条件下，当0．04mol／L硝酸铅标准溶液的用量为1．0mL时，峰电流ip与磷的质量浓度c在0．2～20μg／mL内呈良好线性关系，线性回归方程为ip=-2．39c 54．82，相关系数为0．9876，检出限为0．085μg／mL。用于饲料中磷含量的测定，测定结果的相对标准偏差为1．24％～2．44％，加标回收率为95％～99％。     

萃取富集-火焰原子吸收法测定环境水中铜、锌、铅、镉

用2-琉基苯并噻唑／醋酸丁酯pH7～8萃取体系，预浓集以后，用火焰原子吸收测定环境水中癌量Cu，Zn，Cd、Pb，回收率在95％～105％，相对标准偏差为2％～5％（x=6)，植出限为Cu0．2μg／L，Zn0．08μg／L、Cd0．03μg／L、Pb0．8μg／L。     

十六烷基三甲基溴化铵增敏砂罗铬花青R共振光散射法检测DNA

在pH=3．92的三羟甲基氨基甲烷-HCl缓冲溶液中，阳离子表面活性剂十六烷基三甲基溴化铵对砂罗铬花青R与脱氧核糖核酸(DNA)的共振光散射(RLS)有协同增强作用。考察了影响因素，研究了在优化条件下RLS强度与DNA浓度之间的关系，鱼精DNA和小牛胸腺DNA的线性范围均为0．05—3．00mg／L，检出限分别31．03、35．98μg/L，回收率为97．9％～99．6％，测定结果的相对标准偏差为0．5％-2．1％。     

催化共振光散射法测定痕量亚硝酸根

根据磷酸中亚硝酸根对溶解O2氧化I^-生成I3^-的反应具有明显催化作用,I3^-与结晶紫结合使共振光散射（RLS）增强,建立了测定痕量NO2^-的催化共振光散射法。考察了体系RLS强度的影响因素,优化了反应条件。最大RLS峰位于690．6nm波长处,NO2^-的浓度在2．20～340μg／L范围内与RLS强度增强值呈良好的线性关系,方法检出限为0．68μg／L。用于环境水样中NO2^-测定,与文献方法对照结果满意。     

火焰原子吸收法测定苹果汁中的钠

用浓硝酸及高氯酸消化苹果汁样品，以氯化钾作为电离缓冲剂，建立了测定苹果汁中钠的火焰原子吸收法。方法的线性范围为0～0．6μg／mL，线性回归方程为A=1．0182c 0．0462，相关系数r=0．9971，检出限为0.9μg／L。测定浓缩苹果汁、苹果原汁中钠的相对标准偏差分别为0．6％、1．3％，加标回收率分别为99.0％～lOl.3％、98．0％～103．2％。     

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.