2.5次微分溶出伏安法同时测定人脑中铜,铅,镉,锌

本文通过硝酸－硫酸混合酸消化脑样，在０．０３ｍｏｌ／ＬＨＣｌＯ４底液中，采用悬汞电极２．５次微分阳极溶出伏安法同时测定人脑中铜、铅、镉、锌四种微量元素。在选定的实验条件下，所述元素的浓度在５～１００ｎｇ／ｍＬ范围内与峰高成线性关系。用于人脑中铜、铅、镉和锌的分析，其相对标准偏差分别为６．５％、１０．５％、１２．７％和３．１％，其回收率为９８．０％、９４．０％、１０２．０％和１０４．０％。     

一种在线液—液萃取微型多用分相器的设计和应用：IV.流动注射液— …

设计了在线液－液萃取多用重分布相器及相应流动注射流路系统与ＩＣＰ－ＡＥＳ法联用。具有良好的分析性能，通过对矿石中某些重稀土元素在硝酸介质中被ＴＢＰ萃取的应用研究表明钇，镱，铒的检出限（３σ）分别为６．８ｎｇ／ｍＬ，０．２ｎｇ／ｍＬ和１．５ｎｇ／ｍＬ，精密度（ＲＳＤ％）分别为０．２４，０．４７和１．８，进样频率为２５－３０个／ｈ。     

液芯光纤长光路法在水溶液中测定Cr,Cu

测量了低折射率液体和水溶液液芯光纤的导光特性和光谱特性，研究了液芯光纤长光路法在７０％乙醇－水溶液体系和５０％二氧六环－水溶液体系中测定Ｃｒ（Ⅵ）、Ｃｕ（Ⅱ）的方法。液芯光纤长１１０ｃｍ时，测定Ｃｒ、Ｃｕ的灵敏度分别为０．０５２、０．０１７ｎｇ．ｍＬ＾－１；线性范围０－２５、０－２５ｎｇ／ｍＬ；ＲＳＤ值为１．０％－４．８％。对国标ＧＳＢＥ５０ ００９－８８样品和明胶中铬的测量值与标准值或ＡＡＳ测量     

乙基磺原酸钾—MIBK萃取原子吸收测定重晶石中铅,镉

本文较详细地研究了以乙基磺原酸钾作为金属分离的溶剂萃取试剂测定重晶石中铅，镉的条件，并确定了测定方法，铅和镉与乙基磺原酸钾反应生成白色络合物，该络合物在水相溶液中能定量地萃入甲基异丁基甲酮中。它们的回收率分别为９７％－１０３％和９６％－１０１％。铅和镉分别在０－６μｇ／ｍＬ和０－０．８μｇ／ｍＬ呈线性关系。本法可测定０．０００ｘ％－０．ｘ％Ｐｂ，０．０００ｘ％－０．０ｘ％Ｃｄ．     

病人血样中痕量锗,锶的石墨炉原子吸收光谱法测定

本文运用石墨炉ＡＡＳ法加基体改进技术，测定了５０岁以上病人血清及环境水样中锗和锶的含量。用０．０１ｍｏｌ／ＬＨＮＯ３－０．１％ＴｒｉｔｏｎＸ－１００稀释血清，测定精度可与火焰法媲美。锗，锶的特征量分别为２８ｐｇ和１８ｐｇ；线性范围为０－２５０ｎｇ／ｍＬ和－３５．０ｎｇ／ｍＬ；相对标准偏差（ｎ＝１０）４．１０％和２．４９％；回收率分别为９２．２％－９９．０％和９２．０％１０２％。方法快速准确，结果满     

一种在线液-液萃取微型多用分相器的设计和应用 Ⅳ.流动注射液-液萃取电感耦合等离子体原子发射光谱法测定矿石中稀土元素

设计了在线液－液萃取多用重力分相器及相应流动注射流路系统与ＩＣＰ－ＡＥＳ法联用，具有良好的分析性能．通过对矿石中某些重稀土元素在硝酸介质中被ＴＢＰ萃取的应用研究表明钇、镱、铒的检出限（３σ）分别为：６．８ｎｇ／ｍＬ、０．２ｎｇ／ｍＬ和１．５ｎｇ／ｍＬ．精密度（ＲＳＤ％）分别为０．２４、０．４７和１．８．进样频率为２５～３０个／ｈ．     

以新指示反应高敏催化光度测定痕量钌

钌（Ｒｕ￣Ⅲ）对高碘酸钾氧化无色孔雀绿的显色体系有催化作用，借此催化光度测Ｒｕ￣Ⅲ，灵敏度高。在２０～３０℃下３０～６０ｍｉｎ内，以１ｃｍ吸收池内测得吸光度０．１为可准确测极限，则可测最低浓度为０．０８ｎｇ·ｍＬ￣（－１），若表示为间接摩尔吸光系数则 ＝２．０×１０￣８ｍｏｌ￣（－１）·Ｌ·ｃｍ￣（－１）。工作曲线线性范围为０．０４～０．３６ｎｇ／ｍＬ（室温约为２６℃）．其它贵金属如Ｏｓ￣Ⅷ、Ｒｈ￣Ⅲ、Ａｕ￣Ⅲ、Ａｇ￣Ⅰ、Ｐｄ￣Ⅱ、Ｐｔ￣Ⅳ等至少可允许分别存在２００ｎｇ／ｍＬ、１ｎｇ／ｍＬ、２００ｎｇ／ｍＬ、３０００ｎｇ／ｍＬ、２５ｎｇ／ｍＬ和５ｎｇ／ｍＬ。测定了含所有贵金属和某些其它常见金属人工混合液中的痕量Ｒｕ￣Ⅲ，不含Ｉｒ￣Ⅳ时回收率为９８．５％～１０１．０％，含２．３倍于Ｒｕ￣Ⅳ重量的ｌｒ￣Ⅳ时回收率为１０１．５％～１１２％。     

氢化物—原子荧光光光谱法同时测定黄铜中的砷与锑

试样用硝酸－硫酸分解,试验了酸度、还原剂浓度以及黄铜中常见元素对测定结果的影响,砷、锑的回收率分别为：９６％～１０９％,９０％～９３％,砷、１锑的检出限分别为０．１９ｎｇ＝ｍＬ、０．３１ｎｇ＝ｍＬ,砷、锑的线性范围分别为０．５～２５０ｎｇ／ｍＬ、０．５～５００ｎｇ／ｍＬ。本法用于黄铜标准样品中的砷、锑。结果与标准值吻合。     

连续流动液─液萃取石墨炉原子吸收分析系统的设计及其性能

求文研究了在线液一液萃取石墨炉原子吸收分析技术，设计了一种半自动萃取流路系统及其与石墨炉的接口装置．采用一步萃取操作，比较了直接水相测定和萃取测定ＡＵ和Ｃｄ的结果，表明该流路系统性能较好。在萃取测定中，ＡＵ和Ｃｄ的检出限分别为０．０７７和０．０５５ｎｇ／ｍＬ；精密度为Ａｕ４．１％（５．５ｎｇ／ｍＬ）和Ｃｄ４．９％（０．２５ｎｇ／ｍＬ）标准样品分析结果与推荐值吻合，采样频率为２０—３０／ｈ．     

乳化剂OP对锌,镉,铅电位溶出的增敏作用

在０．０１７ｍｏｌ／Ｌ Ｈ２ＳＯ４－ＨＮＯ３混合酸介质中,乳化剂ＯＰ对锌、镉、铅的电位溶出有显著的增敏作用。在电位－１．５０Ｖ下电解富集６０ｓ时,锌、镉、铅的检出限分别为０．１３μｇ／２０ｍＬ,０．０１６μｇ／２０ｍＬ及０．０２０μｇ／２０ｍＬ;线性范围分别为０．０５～０．５０μｇ／２０ｍＬ,０．０５～０．０８μｇ／２０ｍＬ及０．１０～０．８０μｇ／２０ｍＬ,与峰高呈良好的线性关系。此法用于环境水     

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.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.