ICPMS测定高纯氧化钇中痕量稀土杂质的研究

研究了直接电感耦合等离子质谱（ＩＣＰＭＳ）测定９９．９９９％纯度氧化钇中稀土杂质的方法，详细探讨了仪器工作参数对稀土元素的测定的影响，对各种干扰现象进行了研究，并提出定量校正方法，实验表明，加入内标元素可有效地克服基体效应、接口效应和仪器工作参数漂移的影响。方法的检出限为０．００３～０．０２ｎｇ／ｍｌ，变异系数（ＣＶ％）为０．２％～５．４％，回收率为９０％～１１５％。适合９９．０％～９９．９９９％     

氢化物—原子吸收光谱法测定六味地黄丸中砷和锑

本文建立了氢化物原子吸收光谱法测定六味地黄丸中砷和锑的方法。方法的相对标准偏差砷为１．３％，锑为１．６％，回收率在９０％－１１０％之间，检出限分别为砷０．０６ｎｇ／ｍＬ，锑０．１ｎｇ／ｍＬ，本方法可用于中成药中砷和锑的测定。     

火焰原子吸收光谱法间接测定饲料预混硒中硒

研究了用火焰原子吸收光谱法间接测定饲料预混硒中硒，与其它方法比较，简单、快速，测定的相对标准偏差小于5．0％，回收率为96．3％-104．0％，检出限为0．0005％。     

微型镉柱还原分光光度法测定血清中一氧化氮

建立了微型镉柱还原法间接测定血清中一氧化氮的新方法。本方法还原硝酸根所需时间短，还原率达９５％以上，用于测定混合血清中一氧化氮。检测范围为０－１０００μｍｏｌ／Ｌ，相对标准偏差为１．７０％－２．４９％，对ＮＯ＾－３的回收率为９５．８％－１０４．０％，对ＮＯ＾－２的回收率为９３．６％－９６．８％。     

气相色谱法测定环境空气和废气中的2-丁酮和苯

用活性炭吸附环境空气和废气中的2－丁酮和苯，经二硫化碳解吸后用气相色谱法测定。方法的回收率2－丁酮为86．2％－104．6％， 为91．3％－105．7％。相对标准偏差2－丁酮为2．5％－2．8％，苯为2．5％－3．8％，当采样体积为20L，解吸液体积为2.00ml，进样体积为2μl时，2－丁酮和苯的最低检测浓度分别为0.03mg.m^-3和0.01mg.m^-3。     

梨果及土壤中亚胺唑及其代谢物的气相色谱分析

 介绍了杀菌剂亚胺唑及其代谢物ＩＢＣ－０１在梨果实及土壤样品内的提取、净化方法以及气相色谱的分析测定方法。保留时间：亚胺唑为３８．３６ｍｉｎ，ＩＢＣ－０１为１７．０１ｍｉｎ。变异系数：亚胺唑为０．４５％～１５．５３％，ＩＢＣ－０１为３．０３％～９．５２％。回收率：亚胺唑为８８．２８％～９８．５％，ＩＢＣ－０１为８４．９８％～９８．１３％。     

流动注射在线萃取色谱分离原子吸收光谱法测定痕量铂

研究了流动注射在线分离富集原子吸收光谱法测定痕量铂的方法。以自制的GDX501-TBP萃取树脂为微型分离柱，在优化后的分离富集条件下，进样时间为60s，洗脱时间为45s。在线分离测定时间为3min，方法检出限为0．25μg/L，线性范围10—600μg/L，加标回收率为97．8％-103．6％，相对标准偏差3．49％-4．25％。方法已用于矿物管理样中铂的测定。     

石墨炉原子吸收光谱法测定蘑菇中的镉、铅

采用石墨炉原子吸收光谱法测定蘑菇中的镉、铅，以磷酸二氢铵和硝酸镁作混合基体改进剂，提高了测定的灰化温度，消除了基体干扰。方法简便，快速，准确度高。镉和铅的相对标准偏差为3．7％-6．0％和7．3％-7．9％；回收率为98％-106％和98％-104％；检出限为0．009μg/g和0．032μg/g。     

顶空氢化物火焰原子吸收法测定铜精矿中锑

介绍了顶空氢化物火焰原子吸收法测定铜精矿中锑的方法，讨论了锑测定的量佳条件，方法的灵敏为０．０２μｇ，相对标准差（ｎ＝８）５．４％，标准加入法的回收率为８４．４％－９３．５％。     

梨果及土壤中亚胺唑及其代谢物的气相色谱分析

介绍了杀菌剂亚胺唑及其代谢物ＩＢＣ－０１在梨果实及土壤样品内的提取、净化方法以及气相色谱的分析测定方法。保留时间：亚胺唑为３８．３６ｍｉｎ，ＩＢＣ－０１为１７．０１ｍｉｎ。变异系数：亚胺唑为０．４５％～１５．５３％，ＩＢＣ－０１为３．０３％～９．５２％。回收率：亚胺唑为８８．２８％～９８．５％，ＩＢＣ－０１为８４．９８％～９８．１３％。     

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.     

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.     

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.