多联吡啶螯合物反相高效液相色谱法分离测定铜(Ⅱ)、钴(Ⅱ)、汞(Ⅱ)

以三联吡啶衍生物６，６”－二甲基－４＇－苯基－２，２＇：６＇，２”－三联吡啶（ＴＰＹ）作柱前显色剂，于ＡｃｃＱ－Ｔａｇ柱上，用内含２．０×１０～（－６）ｍｏｌ／Ｌ ＴＰＹ和０．６ ｍｏｌ／Ｌ　ＮａＡｃ－ＨＡｃ缓冲溶液（ｐＨ＝３．５）的甲醇－水溶液（５５：４５，Ｖ／Ｖ）作流动相，流速为１．０ ｍＬ／ｍｉｎ，并以紫外－可见检测器于３１０ｎｍ处进行检测，开发了一种 ＲＰ－ＨＰＬＣ法同时分离测定铜（Ⅱ）、钴（Ⅱ）、汞（Ⅱ）的方法。该方法简便快速，灵敏度高，对于铜、钴、汞的检测限分别是０．００２０、０．００５５和０．００４０ｍｇ／Ｌ。用于实际样品测定，结果满意。     

化学衍生—高效液相色谱法同时测定铅（Ⅱ）和汞（Ⅱ）

从吡啶－２－乙醛苯甲酰腙作柱前衍生试剂，在优化了衍生和色谱条件下实现了用高效液相以谱法同时测定铅和汞离子，在ｐｈｅｎｏｍｅｎｅｘｓｐｈｅｒｅｘＣ１８色谱柱上，用甲醇－水（６５：３５，Ｖ／Ｖ），作流动相，于２４８ｎｍ处检测，得到线性良好的工作曲线，铅和汞的最低检测限分别为２．５５μｇ／Ｌ和７．２９μｇ／Ｌ。分析了环境水样品和合成水样，铅和汞的标准加入回收率分别为９８．３％～１０１．７％和９８．０～１     

1-(2-噻唑偶氮)-2-萘酚螯合物反相高效液相色谱法分离测定铜(Ⅱ)、铁(Ⅱ)和镍(Ⅱ)

以１－（２－噻唑偶氮）－２－萘酚（ＴＡＮ）作柱前显色剂，于ＯＤＳ柱上，用内含０．１ｍｏｌ／ＬＬｉＣｌ，５×１０－６ｍｏｌ／Ｌ ＴＡＮ和ＨＡｃ－ＮＨ４Ａｃ缓冲溶液（ｐＨ ５．５）的甲醇－水溶液（８０：２０，Ｖ／Ｖ）作流动相，流速为０．６ｍＬ／ｍｉｎ，并以紫外－可见检测器于５９０ｎｍ处进行检测，发展了一种ＲＰ－ＨＰＬＣ法同时分离测定铜（Ⅱ）、铁（Ⅱ）、镍（Ⅱ）的方法，方法灵敏度高，对于铜、铁、镍的检测限分别为１μｇ／Ｌ， ２ μｇ／Ｌ和 ０．４ μｇ／Ｌ。用于实际样品测定，结果满意。     

活性氧化铝富集火焰原子吸收法测定铬（Ⅲ）和铬（Ⅵ）

研究了内装活性氧化铝的微型柱流动注射富集分离火焰原子吸收光谱法（Ｆｌ－ＦＡＡＳ）测定水体中μｇ／Ｌ级的Ｃｒ（Ⅲ）、Ｃｒ（Ⅵ）。用０．２ｍｏｌ／Ｌ氨水将活性氧化铝转为碱式以吸附Ｃｒ（Ⅲ），１ｍｏｌ／Ｌ硝酸洗脱；用０．０１ｍｏｌ／Ｌ的硝酸将活性氧化铝转为酸式以吸附Ｃｒ（Ⅵ），０．２ｍｏｌ／Ｌ的氨水洗脱，洗脱液直接送到喷雾器中。进样３０ｓ，浓度富集２５倍。两种价态离子的校正曲线浓度范围在１～５０μｇ／Ｌ之间，检测限分别为０．６和０．７μｇ／Ｌ，样品分析速率为６０样／ｈ。研究了共存离子的干扰情况，实际水样中的加标回收率在８５％～１０５％之间。     

氯化血红素模拟过氧化物酶高效液相色谱柱后衍生法测定过氧化氢和水溶性有机过氧化物

研究了氯化血红素（Ｈｅｍｉｎ）模拟辣根过氧化物酶（ＨＲＰ），对羟基苯乙酸（ＰＨＰＡＡ）作 底物，高效液相色谱（ＨＰＬＣ）柱后衍生荧光法测定Ｈ２Ｏ２和水溶性有机过氧化物的方法。采用 Ｈｅｍｉｎ作催化剂柱后衍生反应的最佳ｐＨ值约为１１，与荧光检测ｐＨ值一致，使得以往ＨＰＬＣ 柱后衍生方法所需的高压泵从３台减少到２台，而一些不能作为ＨＲＰ底物的羟烷基过氧化 物在ｐＨ值≥１０的溶液中迅速水解为Ｈ２Ｏ２从而得到测定。优化了测定Ｈ２Ｏ２和甲基过氧化 氢（ＣＨ３ ＯＯＨ， ＭＨＰ）的条件。最佳条件下 Ｈｅｍｉｎ方法测定 Ｈ２Ｏ２的检测限为 ９．０ × １０－９ ｍｏｌ／Ｌ， 测定 ＭＨＰ的检测限为 ２．０ × １０－７ ｍｏｌ／Ｌ。     

用2—羟基—3—羧基—5—磺酸基苯重氮氨基偶氮苯流动注射分光光度法测定汞

研究了在乳化剂ＯＰ存在下，２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳＤＡＡ）－汞（Ⅱ）显色体系流动注射分光光度法。用ＰＨ１０．０－１０．５的Ｎａ２Ｂ４Ｏ７－ＮａＯＨ缓冲溶液作载流，汞（Ⅱ）与ＨＣＳＤＡＡ和乳化剂ＯＰ的混合试剂反应形成红色络合物。用于测定汞时，方法的线性范围是０．０５－１．０ｍｇ／Ｌ，检测限为０．０１６ｍｇ／Ｌ，进样频率为１００样／ｈ。直接应用于头发、自来水和废水中微量汞     

金在脱乙酰壳多糖学修饰电极上的电化学行为及分析应用

用脱乙酰壳多糖化学修饰电极为工作电极，阳极溶出伏安法测定痕量金。在ｐＨ１￣２的ＫＣｌ－ＨＣｌ底液中，超始电位０．２０Ｖ，终止电位１．３０Ｖ，富集时间５ｍｉｎ，以－０．１／ｓ扫速阳极溶出，峰电位在１．００Ｖ（ｖｓ．ＳＣＥ），Ａｕ（Ⅲ）浓度在０．１０ｍｇ／Ｌ￣１０ｍｇ／Ｌ范围内与峰高呈线性关系。在富集１０ｍｉｎ时，可检测０．２５ｍｉｇ／ＬＡｕ，大大提高了测定灵敏度，用于矿样测定，无需分离，结果满意。用     

4—（6—甲基—2—苯并噻唑偶氮）间苯三酚反相高效液相色谱分离测定钒钴镍铬

作以新研制的４－（６－甲基－２－苯并噻唑偶氮）间苯三酚为柱前衍生试剂，用含１０ｍｍｏｌ／Ｌ的ｐＨ６．８０的ＨＡｃ－ＮａＡｃ缓冲溶液，１０ｍｍｏｌ／Ｌ ＴＢＡ．Ｂｒ和１×１０＾－４ｍｏｌ／ＬＥＤＴＡ的甲醇－水溶液（７８：２２，Ｖ／Ｖ）作流动相，在Ｃ１８柱上，１１ｍｉｎ内反相ＨＰＬＣ分离测定了Ｃｒ（Ⅵ），Ｖ（Ⅴ），Ｃｏ（Ⅱ），Ｎｉ（Ⅱ）。当Ｓ／Ｎ＝３时，其检出限分别是Ｖ（Ⅴ）５．４５ｎｇ，Ｃｏ（Ⅱ）     

铁,钴,镍的反相高效液相色谱分离和测定

１引言建立了用反相高效液相色谱同时测定铁、钴、镍的分析方法并对Ｍｅｎ＋－二硫腙（ＤＺ）体系的色谱行为进行了探索。较之萃取进样更快速、简便。测定条件为：Ｓｈｉｍ－ＰａｃｋＣＬＣ－ＯＤＳ（φ６×１５０ｍｍ，５μｍ）；流动相：甲醇：水：三氯甲烷（含１％三乙胺）（８０：１０：１０）；流速１ｍＬ／ｍｉｎ；柱温３５℃；检测波长２５４ｎ。线性范围０．０１－２．０ｍｇ／Ｌ；相关系数ｒ＝０．９９９ｌ～０．９９９８；检测限为０．００２３～０．００５０ｍｇ／Ｌ；相对标准偏差为１．８％－２．７％；回收率为９６％－１０４…     

萃取—缝管原子捕集原子吸收法测定水中碲（Ⅳ）和磅（Ⅵ）

研究了碲（Ⅳ）和碲（Ⅵ）在ＤＤＴＣ－ＣＣｌ４体系中的萃取和反萃取行为，并用缝管原子捕集技术结合火焰原子吸收法测定了水样中的碲（Ⅳ）和碲（Ⅵ），特征浓度为１．２ｇ／Ｌ／１％吸收，检出限０．２μｇ／Ｌ，相对标准偏差１．７％，富集倍中达１００％。     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.