流动注射吸光光度法测定饲料样品中钙

基于钙色素（Ｃａｃｉｃｈｒｏｍｅ）在碱性条件与钙形成灵敏的红色络合物这一显色反应，在ＦＩＡ－２４００型流动注射仪上，用吸光光度计做检测器，建立了测定饲料样品中钙的流动注射吸光光度法，分析测定条件为０．２０ｍｏｌ．Ｌ＾－１氢氧化钠－０．２ｇ．Ｌ＾－１钙色素溶液为显色剂，以３０ｇ．Ｌ＾－１三乙醇胺溶液为载流，测定波长为５１０ｎｍ，钙的浓度在０～１０．０μｇ，．ｍｌ＾－１有良好线性关系，适用于测定各种饲     

停流流动注射—动力学方法多组份同时测定的研究：铁（Ⅱ）,钛（Ⅲ）和…

依据诱导反应原理，提出了同时测定多组份的动力学方法，并以停流流动注射分析研究了Ｆｅ（Ⅱ），Ｔｉ（Ⅲ）及Ｖ（Ⅳ）诱导的Ｃｒ（Ⅵ）－Ｉ＾－反应体系，建立了铁，钛和钒同时测定的条件。对铁，钛和钒测定的线性范围分别为０－２．２μｇ／ｍｌ，０－３．１μｇ／ｍｌ及０－１．８μｇ／ｍｌ，检测限分别为０．０１２，０．０２０和０．０１８μｇ／ｍｌ。     

流动注射荧光法测定片剂中氨酰心安的含量

本文研究了片剂中氨酰心安的流动注射荧光分光光度分析法，进样频率８０次／ｈ，氨酰心安浓度在０－５．７５μｇ／ｍｌ范围内与相对荧光强度呈线性关系，相关系数０．９９９。用于测定片剂中氨酰心安的含量，结果满意。     

饮料食品中Ge－132和Ge~（4＋）含量测定研究

本文报告了在０．０１ｍｏｌ／ＬＣＴＡＢ体系中，以Ｆ－为掩蔽剂、苯芴酮显色、用分光光度法测定饮料食品中Ｇｅ－１３２含量，最低检测限０．０５４μｇ／ｍＬ；线性范围０．５４～２７．１４μｇ／ｍＬ；回收率９６．３％～１０１．５％，并确定了Ｇｅ－１３２摩尔吸收系数（ε）３．３９×１０４。用本法测定了康寿茶、矿泉水和博士奶中Ｇｅ－１３２含量，灵敏度高、重现性和准确度好。用盐酸化本体系，研究了二氧化锗（Ｇｅ~（４＋））的含量测定，其最低检测限０．０２１μｇ／ｍＬ；线性范围１．０～２１．０μｇ／ｍｌ；回收率９５．８％～１０２．８％，Ｇｅ－１３２不干扰。饮料食品中同时存在Ｇｅ－１３２和Ｇｅ（４＋）时，本体系可分别测定两者含量。     

催化反应吸光光度法测定痕量银

研究了Ａｇ对亚铁氰化钾与邻菲罗啉显色反应的催化研究，建立了痕量银的催化吸光光度法。灵敏度为１．０×１０＾－３μｇ．ｍｌ＾－１，线性范围为０－０．４μｇ／２５ｍＬ。用于水样中痕量银的测定，结果满意。     

快速测定蜂王浆中蜂王酸的分光光度法研究

本文提出了用差示分光光度法和一阶导数分光光度法测定蜂王浆中蜂王酸的含量，差示光谱最大测定波长为（＋）２２８．０ｎｍ；一阶导数光谱测定波长为（＋）２０４．５ｎｍ和（－）２３３．５ｎｍ。线性范围为０－２０μｇ／ｍｌ（差示分光光度法）和０－１５μｇ／ｍｌ（一阶异数分光光度法）。二法在实际测定中具有操作简便，快速和准确度高等优点。     

碱性氢化物发生—火焰原子吸收光谱法测定锡

对Ｓｎ－ＮａＯＨ－ＫＢＨ４体系进行了系统研究，采用三乙醇胺－ＥＤＴＡ联合干扰抑制剂，可消除一定量铁及合金元素的干扰，对于锡含量小于０．０１％的试样，用苯萃取锡后所有元素不干扰测定。测定液中锡量为０－４μｇ／１０ｍｌ，呈线性关系，灵敏度为０．００４ｍｇ／Ｌ／１％，检出限为０．００８ｍｇ／Ｌ，测定钢中大于０．００１％锡，结果满意。     

双显色剂双波长系数补偿法同时测定铝和铁的研究

本文提出了一种双显色双波长系数补偿法测定食品中微量铝、铁的新方法，在ｐＨ＝６．２缓冲液中，以络天青Ｓ为显色剂选择６２２／５０６ｎｍ波长对测定铝，以５－Ｂｒ－ＰＡＤＡＰ为显色剂选择５６０／６６０ｎｍ波长对测定铁，不经分离可直接测定样品中的铝、铁，铝量在０．２～５．０μｇ／２５ｍｌ、铁量在１．０～１５．０μｇ／２５ｍｌ符合朗伯比耳定律。本法应用于食品中铝、铁测定，得到较满意结果。     

邻硝基苯基荧光酮流动注射分光光度法测定微量钛

本文研究了以邻硝基苯基荧光酮－溴化十六烷基三甲基铵为试剂的流动注射分光光度测定钛的新方法。该方法分析频率达到１００次／ｈ，线性范围为０～１．０μｇ／ｇ方法重性好，用于合金钢及纯铝中钛的测定，结果满意。     

二乙基二硫代氨基甲酸钠流动注射萃取分光光度法测定矿石中微…

本文对二乙基二硫代氨基甲酸钠（铜试剂）－四氯化碳流动注射萃取分光光度法测定矿石中微量铜进行了研究。与手工萃取法相比，本法最大特点是大量Ｍｎ＾２＋无干扰。方法操作简便、快速、可靠、毒性小；增样频率为２０次／小时，ＲＳＤ为３．５％。线性范围为０～１．２８μｇ／ｍｌ。方法用于测定矿石中微量铜，结果满意。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.