流动注射化学发光法测定对苯二酚

采用流动注射技术研究了酸性条件下 ,高锰酸钾与对苯二酚的化学发光行为 ,对影响化学发光强度的诸因素进行了试验和探讨 ,建立了流动注射化学发光法测定对苯二酚的新方法。方法的检出限为 6× 10 - 8g·ml- 1,线性范围为 2 .0× 10 - 78.0× 10 - 5g·ml- 1,对 4 .0× 10 - 6 g·ml- 1对苯二酚进行 11次平行测定 ,相对标准偏差为 1.5 %。方法用于测定废水中对苯二酚的含量 ,结果满意。     

KBrO3-KBr紫外分光光度法测定痕量苯酚

研究了在盐酸介质中以 KBrO3-KBr 紫外分光光度法测定痕量苯酚的条件,在浓度为 0.6mol/L HCl,3×10-5mol/L KBrO3,5×10-4mol/L KBr,6×10-4mol/L KI 溶液中测定苯酚时,线性范围为 0.10～2.5mg/L,表观摩尔吸光系数为 1.89×104L·mol-1·cm-1,Sandell 指数为 4.98μg/cm2.本法已用于测定废水中苯酚.     

双波长吸光光度法同时测定多巴和酪氨酸的研究

研究了双波长吸光光度法同时测定多巴和酪氨酸。在 pH 1 2 .0 0的硼砂 氢氧化钠缓冲介质中 ,多巴和酪氨酸的含量分别在 0～ 2 0 .0 μg·ml-1和 0～ 1 9.0 μg·ml-1范围内呈良好线性关系 ,方法检出限和摩尔吸光系数 :多巴为 0 .2 3 μg·ml-1和 1 .2 0× 1 0 4L·mol-1·cm-1,酪氨酸为 0 .2 7μg·ml-1和 1 .48× 1 0 4L·mol-1·cm-1,方法的灵敏度和和选择性均较好 ,应用于尿液中多巴和酪氨酸的测定。     

7-碘-8-羟基喹啉-5-磺酸与钒显色反应的研究及应用

在 0 .2 0mol·L- 1硫酸介质中 ,用过氧化氢作增敏剂 ,7 碘 8 羟基喹啉 5 磺酸 (Ferron)与钒 (Ⅴ )形成 1∶1的有色配合物 ,在 4 10nm处有最大吸收 ,其表观稳定常数为 4 .5× 10 3 ,摩尔吸光系数ε4 10 为 1.91× 10 3 L·mol- 1·cm- 1,钒浓度在 0 .10～ 2 0 .0 μg·ml- 1范围内符合比耳定律。该方法用于矿样中钒的测定 ,结果满意     

曲利本蓝-氨基糖苷类抗生素的显色反应及其分析应用

曲利本蓝 (TB)与硫酸卡那霉素 (KANA)和硫酸妥布霉素 (TOB)等氨基糖苷类抗生素在pH 2 .0～ 7.0的条件下反应生成蓝色离子缔合物。其最大显色波长位于 680nm(TOB)和 686nm(KANA) ,线性范围分别是 0～ 1 1 .0 μg mL(TOB)和0～ 1 3.0 μg mL(KANA) ,摩尔吸光系数 (ε)分别为 5 .32× 1 0 3(TOB)和 3.64× 1 0 3(KANA)L·mol-1·cm-1;最大褪色波长位于 5 88nm(TOB)和 5 90nm(KANA) ,线性范围均为 0～ 1 1 .0 μg mL ,摩尔吸光系数 (ε)分别为 1 .84× 1 0 4 (TOB)和 1 .1 1× 1 0 4(KANA)L·mol-1·cm-1。当用双波长叠加法时 ,ε值分别为 2 .37× 1 0 4 (TOB)和1 47× 1 0 4 (KANA)L·mol-1·cm-1。探讨了适宜的反应条件及主要的分析化学性质。该方法用于市售药物中氨基糖苷类抗生素的测定。     

磷钼杂多酸光度法测定吲哚乙酸

研究了吲哚乙酸与磷钼杂多酸在浓度为 0 .0 3 mol/L的硫酸介质中发生氧化还原反应 ,形成的还原产物 (钼蓝 )在 NH3-NH4Cl缓冲溶液 (p H8.4)中最大吸收波长为 314 nm,表观摩尔吸光系数 ε值为 3.5 4× 10 4L· mol-1·cm-1 ,吲哚乙酸含量在 5 .0× 10 -7～ 5 .0× 10 -5 mol/L范围内符合比尔定律 ,检出限为 1.0× 10 -7mol/L,对 2 .0 0× 10 -5 mol/L吲哚乙酸测定 10次的相对标准偏差为 6 .42 % ,加标回收率为 94.2 %～ 10 0 .1%     

铈(Ⅳ)-吐温40-对苯二酚化学发光体系测定氢醌乳膏中对苯二酚

讨论了表面活性剂对铈(Ⅳ)氧化对苯二酚化学反应的影响,发现了铈(Ⅳ) 吐温40 对苯二酚化学发光新体系,建立了测定对苯二酚化学发光分析方法,该法测定对苯二酚的线性范围为8.0×10-7～5.0×10-5mol·L-1,检出限为5.0×10-7mol·L-1,相对标准偏差为2.5%(5.0×10-6mol·L-1对苯二酚,n=11)。该法应用于测定氢醌乳膏中的对苯二酚,结果满意。     

L-半胱氨酸自组装膜电极的表征及其对对苯二酚的差分脉冲伏安法测定

研究了 L-半胱氨酸自组装膜修饰金电极 ( L - Cys Au/SAMs)催化对苯二酚氧化的电化学行为 ,发现该膜电极大大降低了对苯二酚的氧化电位。采用水平衰减全反射 ( ATR) FTIR光谱技术和 K3Fe( CN) 6 电化学探针对 L- Cys Au/SAMs进行了表征。用差分脉冲伏安法 ( DPV)测定其氧化峰电流与对苯二酚的浓度在 2 .0× 1 0 - 6～ 2 .0× 1 0 - 4mol· L- 1范围内呈良好的线性关系 ,相关系数 0 .9986,检出限 4.0×1 0 - 7mol·L- 1。该电极用于模拟废水样的测定 ,结果满意。     

紫外光谱区分光光度法测定微量铁

铁与磺基水杨酸在pH5.6～6.0范围内形成的1:2络合物,在紫外光谱区波长约248nm处有一尖形吸收峰,灵敏度很高,摩尔吸光系数ε=2.82×10~4L·mol~(-1)·cm~(-1),比可见光区ε=4.25×10~3L·mol~(-1)·cm~(-1)提高了5倍,利用导数法可以提高到ε=1.20×10~5L·mol~(-1)·cm~(-1),是可见光区的24倍。     

阻抑-褪色光度法测定痕量硅

基于NH3 NH4 Cl缓冲溶液介质中 ,Si 对H2 O2 氧化十六烷基三甲基溴化铵 姜黄素离子缔合物的褪色反应的抑制作用 ,提出了测定痕量硅新的高灵敏的褪色光度法。该方法的表观摩尔吸光系数ε50 0=5 .70× 10 5L·mol-1·cm-1;线性范围为 0 .4～ 3.6 μg/L ;线性回归方程ΔA =2 .2 3× 10 -4 + 0 .0 2 0 17CSi (μg/L) ;相关系数r =0 .9999;测定下限为 2 0× 10 -8g/L。本法用于人发样和水样中痕量硅的测定 ,结果满意。     

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.