因子分析-氢化物发生原子吸收法分析砷的形态

报道了用流动注射氢化物发生原子吸收法（ＦＩ－ＨＧＡＡＳ）对砷４种形态,Ａｓ,ＤＭＡ,ＭＭＡ）的混合体系进行测量后,根据吸光度加和性原则,用因子分析法（ＴＦＡ）对测定值进行解析,从而测定了混合体系中砷存在形态的数目、种类和含量。实验结果表明,不同酸度介质中不同形态砷校正曲线的斜率可作为相应的目标检测向量,应用于μｇ／Ｌ级低浓度砷的形态分析,平均回收率为９３．９％,结果令人满意。     

砷钼杂多酸／罗凡明B三元离子缔合物的二级散射光谱研究

在０．１２ｍｏｌ／ＬＨ２ＳＯ４介质中,Ａｓ（Ⅴ）、Ｍｏ（Ⅵ）与罗丹明Ｂ形成砷钼杂多酸／罗丹明Ｂ三元缔合物,它在λｅｘ／λｅｍ为３２５ｎｍ／６５０ｎｍ波长处产生一个灵敏的二级散射峰。据此建立了一个测定１～２０ｎｇ／ｍＬ Ａｓ的二级散射光谱分析新方法。本法具有灵敏度高、选择性好、操作简便等特点。     

微电极阵列若干电化学特性的研究

用微电子平面工艺制备了带宽和边长分别为１０、２０、３０μｍ的带形和正方形微电极阵列（ＢＭＥＡ和ＳＭＥＡ）。在Ｋ３Ｆｅ（ＣＮ）６溶液中研究了它们的电化学特性。边长为１０μｍ的ＳＭＥＡ（工作电极总面积仅为９×１０＾－３ｍｍ＾２）有最大的电流密度（１２．１μＡ／ｍｍ＾２）和最短的响应时间（５ｓ）。同一硅片中任选５个ＳＭＥＡ其Ｈ２Ｏ２工作曲线的线性范围为０．１～５ｍｍｏｌ／Ｌ，平均斜率为２２０ｎＡ／ｍｍｏ     

砷锑钼三元杂多酸光化学光度法测定痕量砷

砷锑钼三元杂多酸光化学分光光度法是测定０ ．０４ ～１ ．０ ｍ ｇ／ Ｌ 砷的新方法。在０ ．１２ ｍｏｌ／ Ｌ Ｈ２ Ｓ Ｏ４２ ．０ ×１０ － ４ ｍ ｏｌ／ Ｌ Ｓｂ（ Ⅲ）２ ．０ ×－ ３ ｍ ｏｌ／ Ｌ Ｍｏ（ Ⅵ）４ ％ （ Ｖ／ Ｖ） 甲醇介质中, Ａｓ（ Ⅲ） 、 Ｓｂ（ Ⅲ） 、 Ｍｏ（ Ⅵ） 形成的三元杂多酸被紫外光还原生成三元杂多蓝（λｍ ａ ｘ ＝ ７８０ ｎｍ ） 。实验结果表明,方法具有灵敏度高,选择性好,操作简便等特点。     

高效液相色谱法紫外检测人尿中美托洛尔和α－羟基美托洛尔

 用高效液相色谱法紫外检测人尿中美托洛尔（Ｍ）和α－羟基美托洛尔（ＨＭ）浓度，采用ＳｐｈｅｒｉｓｏｒｂＯＤＳ１２５ｍｍ×４ｍｍｉ．ｄ．（５μｍ）色谱柱，甲醇：水：冰乙酸：三乙胺（７０：３０：０：１２：０：０３）为流动相，紫外检测波长为２１５ｎｍ。Ｍ和ＨＭ的平均回收率分别为９８．５／和９９．８％，日内和日间变异系数均小于４．５％。方法快速、简便、灵敏，可用于药物氧化分型研究。     

高效液相色谱法紫外检测人尿中美托洛尔和α－羟基美托洛尔

用高效液相色谱法紫外检测人尿中美托洛尔（Ｍ）和α－羟基美托洛尔（ＨＭ）浓度，采用ＳｐｈｅｒｉｓｏｒｂＯＤＳ１２５ｍｍ×４ｍｍｉ．ｄ．（５μｍ）色谱柱，甲醇：水：冰乙酸：三乙胺（７０：３０：０：１２：０：０３）为流动相，紫外检测波长为２１５ｎｍ。Ｍ和ＨＭ的平均回收率分别为９８．５／和９９．８％，日内和日间变异系数均小于４．５％。方法快速、简便、灵敏，可用于药物氧化分型研究。     

THE RETENTION BEHAVIOR OF ARSENIC COMPOUNDS ON PRP-X100 COLUMN UNDER ALKALINE CONDITION

 系统地研究了碱性条件下（ｐＨ８～１０．８）Ａｓ３＋，Ａｓ５＋，ＭＡ，ＤＭＡ和ＡＢ等砷化合物在ＰＲＰ－Ｘ１００阴离子交换柱上的保留行为。用火焰原子吸收光谱（ＦＡＡＳ）测定从ＨＰＬＣ分离的砷化合物，即通过一根１ｍ×０．２３ｍｍｉ．ｄ．不锈钢毛细管，将ＨＰＬＣ柱出口与ＦＡＡＳ的雾化器连接起来，采用乙炔／空气火焰，在１９３．７ｎｍ处测定。具体研究了两个流动相（２０ｍｍｏｌ／ＬＮＨ４ＨＣＯ３和２．５ｍｍｏｌ／Ｌ对－羟基苯甲酸－１．０ｍｍｏｌ／Ｌ苯甲酸水溶液）。     

阻化动力学光度法测定铂

在磷酸介质中,铂（Ⅱ）对Ｍｎ（Ⅶ）－Ｍｎ（Ⅱ）－ＤＡｐＡｍ体系显色反应有阻抑作用,据此建立了一种测定铂的动力学分析方法,并研究了该阻抑反应的动力学参数。方法的线性范围为２０－２００μｇ／Ｌ;检测限为１０μｇ／Ｌ。该体系灵敏度高,稳定性好,用于催化剂中铂的测定,结果满意。     

THE RETENTION BEHAVIOR OF ARSENIC COMPOUNDS ON PRP-X100 COLUMN UNDER ALKALINE CONDITION

系统地研究了碱性条件下（ｐＨ８～１０．８）Ａｓ３＋，Ａｓ５＋，ＭＡ，ＤＭＡ和ＡＢ等砷化合物在ＰＲＰ－Ｘ１００阴离子交换柱上的保留行为。用火焰原子吸收光谱（ＦＡＡＳ）测定从ＨＰＬＣ分离的砷化合物，即通过一根１ｍ×０．２３ｍｍｉ．ｄ．不锈钢毛细管，将ＨＰＬＣ柱出口与ＦＡＡＳ的雾化器连接起来，采用乙炔／空气火焰，在１９３．７ｎｍ处测定。具体研究了两个流动相（２０ｍｍｏｌ／ＬＮＨ４ＨＣＯ３和２．５ｍｍｏｌ／Ｌ对－羟基苯甲酸－１．０ｍｍｏｌ／Ｌ苯甲酸水溶液），并系统研究了ｐＨ值和缓冲液浓度对上述５个砷化合物的保留时间的影响，发现对于２０ｍｍｏｌ／ＬＮＨ４ＨＣＯ３体系，在ｐＨ８．７时，ＡＢ，Ａｓ３＋，ＤＭＡ可以得到完全分离，通过梯度洗提（ｐＨ８．７到９．８，流速１．６５ｍＬ／ｍｉｎ），在１５ｍｉｎ内上述５个砷化合物可以得到良好分离；对于２．５ｍｍｏｌ／Ｌ对－羟基苯甲酸－１．０ｍｍｏｌ／Ｌ苯甲酸体系，在ｐＨ９．０及流速１．５ｍＬ／ｍｉｎ时，可以在１２ｍｉｎ内将上述５个砷化合物分离。     

电位型砷传感器的研究及分析应用

以ＣＴＭＡＢ修饰碳糊电极将砷钼杂多酸固定于碳糊电极表面,使其表面形成了杂多酸薄膜。该电极对４．００×１０＾－６～１．００×１０＾－３ｍｏｌ／Ｌ范围的砷钼杂多酸有能斯特响应,斜率为４７．５ｍＶ／ｐＡｓ（ｖ）,从而可间接测定砷。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.     

Exploring the scope of the Gewald reaction: Expansion to a four-component process

An efficient four-component reaction was developed to take advantage of the reactivity of the 2-aminothiophene-3-carbonitrile functionality, which is obtained during the classical three-component Gewald reaction. Various α-methylene bearing ketones were reacted with malononitrile, elemental sulfur, and aryl/heteroarylnitrile derivatives in t-BuOH/NaOH to afford 2-arylthieno[2,3-d]pyrimidin-4-amines in high yields. Preliminary studies revealed the photophysical properties of the products and their potential for use as metal sensors.