高效毛细管电泳－安培检测法测定牙膏中丙三醇和山梨醇

 用高效毛细管电泳－安培检测装置，以２００μｍ铜圆盘电极为工作电极，在碱性介质中，建立了分离测定丙三醇和山梨醇的最佳实验条件。结果表明：平均理论塔板数为２．４×１０５／ｍ，丙三醇和山梨醇的浓度检测限分别为３００μｇ／Ｌ和２００μｇ／Ｌ，线性范围接近３个数量级。在５．００～５０．０ｍｇ／Ｌ内，丙三醇和山梨醇的相关系数分别为０．９９９７和０．９９９５。样品测定结果与用高效液相色谱法测定的结果基本一致，回收率在９２％～１０４％之间。     

反相高效液相色谱法快速测定复合甜味剂中Aspartam

利用反相高效液相色谱法快速测定各种复合甜味剂中Ａｓｐａｒｔａｍ,用ＯＤＳ短柱（ＵｌｔｒａｓｐｈｅｒｅＸＬ－ＯＤＳ,３μｍ,４．６ｍｍｉ．ｄ．×７．０ｃｍ）,以ＣＨ３ＯＨ－０．０２ｍｏｌ／ＬＮＨ４Ａｃ为流动相进行分离,紫外检测器２２０ｎｍ检测,根据色谱保留时间结合对组分不停泵紫外光谱扫描进行定性,用外标法峰高定量,方法最小检出浓度为５μｇ／Ｌ,标准曲线在４０～２００ｍｇ／Ｌ浓度范围内呈线性,相关系数在０．９９９以上,平均添加回收率为９２％,其它复合组分不干扰测定。方法简便、快速、灵敏,非常适合于日常监督检测。     

在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收法测定水中痕量铅

应用高效的在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收系统直接测定水呈痕量铅。实验用内装２００ｍｇＡｍｂｅｒｌｉｔｅＸＡＤ－４键合的５－磺酸－８羟基喹啉螯合树脂的锥形柱,在ＰＨ９条件下样品流速为８．０ｍＬ／ｍｉｎ,９０ｓ采样,用０．５ｍｏｌ／Ｌ Ｈｃｌ洗脱,在分析速度为３０样／ｈ,获得３６倍的富集,经石英缝管增敏,灵敏度提高达１１５倍,线性范围为０－２００μｇ／Ｌ,检出限为１μｇ／Ｌ。铅含量水平５０μｇ／Ｌ的水样连续测定１１次的相对标准偏差２．５％,可直接测定水体中μｇ／Ｌ级的铅。     

锑（锡）—Ferron—Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ２ＳＯ４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者（Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水，地下水和天然水中痕量锑和锡的测定，同时对电话性络合物的组成，极谱波的性质和电极过程机理也     

锑（锡）－Ferron－Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ＿２ＳＯ＿４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水、地下水和天然水中痕量锑和锡的测定。同时对电活性络合物的组成、极谱波的性质和电极过程机理也作了讨论和研究。     

碳纤维束汞膜电极二次微分阳极溶出伏安法测定锌中微量铅

本文提出了碳纤维束汞膜电极二次微分阳极溶出伏安法测定锌中微量铅的方法，对溶解氧，扫描速度，电极清洗时间，富集电位和时间及酸度的影响作了讨论。方法的线性范围为１．９－８０μｇ／Ｌ；检测下限达到１．９μｇ／Ｌ；对国家保证参考物质锌样中铅的测定，相对标准偏差和相对误差分别为２．６％和０．６５％，结果令人满意。     

单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）

以酒石酸－乙二胺为淋洗液的单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）。淋洗液最佳浓度为４．０ｍｍｏｌ．Ｌ￣（－１）、酒石酸／１．０ｍ　ｍｏｌ·Ｌ￣（－１）乙二胺。最低检测限为Ｎａ￣＋０．０５μｇ／ｍＬ、　Ｆｅ３＋　０．４５μｇ／ｍＬ。电导检测灵敏度为２．０μｇ／ｃｍ。线性范围Ｎａ￣＋、Ｆｅ３＋０．２～１．５×１０３μｇ／ｍＬ、２．５～１．０×１０３μｇ／ｍＬ。相对平均偏差Ｎａ￣＋为２．０３％、Ｆｅ３＋为０．８３％。平均回收率Ｎａ￣＋为９８．２６％、Ｆｅ３＋为９７．６２％。本法简便、快速、准确、选择性好。     

三波长K系数分光光度法同时测定痕量磷,砷,硅

１引言以碱性染料光度法同时测定磷、砷、硅已有报道，但需加入掩蔽剂或经还原－萃取等分离。本文用三波长Ｋ系数法原理，由计算机选出最佳波长组合，不经分离、掩蔽，于一份试液中同时测定痕量磷、砷、硅，其线性范围分别为４０．０～２４０．０μｇ／Ｌ、３２．０～１２０．０μｇ／Ｌ、３２．０～３２０．０μｄ／Ｌ。用于合成样品测定，结果令人满意。２实验部分２．１仪器与试剂７２２型光栅分光光度计。硅标准溶液：用高纯ＳｉＯ２（９９．９９％）以常法熔融配成ｐＨ约１．５的溶液，含硅０．１００ｇ／Ｌ；磷标准溶液：用ＫＨ２ＰＯ…     

毛细管气相色谱法对大麻中主要成分的定性定量分析

采用毛细管气相色谱法测定大麻中大麻酚、四氢大麻酚和大麻二酚的含量。以氯仿为提取溶剂,甲醇为色谱溶剂,用ＨＰ－５（１０ｍ×０．５３ｍｍ×２．６５μｍ）柱,以柱温２２０℃进行测定。大麻二酚、四氢大麻酚和大麻酚在２０～１２０ｍｇ／Ｌ的浓度范围内线性关系良好,ｒ分别为０．９９９４,０．９９９１和０．９９９５,回收率分别为９７．３％～１０４．０％,９７．３％～１０６．６％和９５．３％～１０２．４％,最低检测限均为０．２μｇ／ｍＬ。利用３种主要成分保留时间的良好重现性也可进行定性。方法简便、快速、准确、灵敏。     

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     

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.     

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.