PIA活性碳纤维在线富集水样中痕量元素及ICP—AES检测

本文研究了新型吸附材料－活性碳纤维的在线分离富集特性，用ＦＩ活性碳纤维填充的锥形柱，实现痕量金属元素Ｚｎ、Ｐｂ、Ｎｉ、Ｃｏ、Ｃｄ、Ｍｎ的在线富集。经ＨＮＯ３洗脱后，由ＩＣＰＡＥＳ检测，测定速率达３０样／ｈ，检出限（ｎｇ／ｍＬ）分别为：０．４（Ｚｎ）、４．０（Ｐｂ），０．９（Ｎｉ）、０．４（Ｃｏ）、０．４（Ｃｄ）、０．７（Ｍｎ），富集柱可使用多次。     

FIA活性碳纤维在线富集水样中痕量元素及ICP－AES检测

本文研究了新型吸附材料－活性碳纤维的在线分离富集特性，用ＦＩ活性碳纤维填充的锥形柱，实现痕量金属元素Ｚｎ、Ｐｈ、Ｎｉ、Ｃｏ、Ｃｄ、Ｍｎ的在线富集。经ＨＮＯ３洗脱后．由ＩＣＰ－ＡＥＳ检测，测定速率达３０样／ｈ，检出限（ｎｇ／ｍＬ）分别为：０．４（Ｚｎ）、４．０（Ｐｈ）．０．９（Ｎｉ）、０．４（Ｃｏ）、０．４（Ｃｄ）、０．７（Ｍｎ），富集柱可使用多次。     

柱前衍生／流动注射微柱预富集和ICP－AES法测定高纯氧化钅兰中痕量非稀土元素

利用自合成的碳硅凝胶为吸附材料，以铜试剂（ＮａＤＤＴＣ）为柱前衍生试剂，实现了Ａｌ（Ⅲ）、Ｃｒ（Ⅵ）、Ｃｕ（Ⅱ）、Ｆｅ（Ⅲ）、Ｖ（Ⅴ）流动注射（ＦＩ）微柱预富集．以稀ＨＮＯ３停流洗脱富集物，ＩＣＰ－ＡＥＳ法测定洗脱液中上述元素．在优化条件下，富集倍数近１０倍，检出限为ｎｇ／ｍＬ级，ＲＳＤ＜５．０％（ｎ＝７），方法用于高纯Ｌａ２Ｏ３中非稀土杂质测定，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。     

流动注射在线共沉淀预富集火焰原子吸收法测定痕量铜

研究了以Ｎｉ＾２＋－ＤＤＴＣ为共沉淀载体，流动注射在线共沉淀预富集－火焰原子吸收光谱法测定痕量铜的体系，在０．３ｍｏｌ．Ｌ＾－１的硝酸介质中，铜离子在编织反应器中与Ｎｉ＾２＋－ＤＤＴＣ（产生共沉淀，并被收集在编织器内壁上，用甲基异丁基酮（ＭＩＢＫ）在线洗脱沉积物并引入火争原子化器中测定。当富集时间为４０ｓ时，４０μｇ．Ｌ＾－１的铜１０次测定的相对标准偏差为３．０％，灵敏度提高６０倍，检出限（３σ）     

柱前衍生／流动注射微柱预富集和ICP—AES法测定高纯氧化镧中痕量非

利用自合成的碳硅凝胶为吸附材料，以铜试剂（ＮａＤＤＴＣ）为柱前衍生试剂，实现了Ａｌ（Ⅲ）、Ｃｒ（Ⅵ）、Ｃｕ（Ⅱ）、Ｆｅ（Ⅲ）、Ｖ（Ｖ）流动注射（ＦＩ）微柱预富集。以稀ＨＮＯ３停流洗脱富集物，ＩＣＰ－ＡＥＳ法测定洗脱液中上述元素。在优化条件下，富集倍数近１０倍，检出限为ｎｇ／ｍＬ级，ＲＳＤ〈５．０％（ｎ＝７），方法用于高纯Ｌａ２Ｏ３中非稀土杂质测定，结果满意。     

高效液相色谱法检测弹性蛋白中锁链素

用高效液相色谱技术对弹性蛋白水解液中锁链素进行了测定。单一锁链素,锁链素、酪氨酸、苯丙氨酸混合液及弹性蛋白水解液经Ｃ１８柱分离,甲醇－水（２８,Ｖ／Ｖ）洗脱,紫外检测器２８０ｎｍ检测。锁链素与酪氨酸峰面积比（ＣＡ）和峰高比（ＣＨ）分别为１．４％和３．４％,标准曲线浓度范围０．１６～０．６４ｍｇ／Ｌ时相关系数为０．９９５６。结果表明：上述色谱条件可定量测定弹性蛋白中锁链素含量,无需将锁链素与水解液中其它氨基酸加以分离,而仅需同其它２７５ｎｍ有吸收的组分区分。     

液相色谱法测定生物发酵液中水溶性维生素的研究

本文采用反相离子对色谱测定了生物发酵液中的七种水溶性维生素。提出了用自行装填的酸性氧化铝（０．１９～０．１５ｍｍ）前置柱，和５％乙酸洗脱样品的前处理方法；并就有关的色谱条件进行了选择。色谱柱为ＮｏｖａＰａｋＣ１８；流动相Ａ液为０．０５ｍｏｌ／Ｌ庚烷磺酸盐（ＰＩＣＢ７），冰乙酸调ｐＨ＝２．５；Ｂ液为甲醇＋三乙胺（１００＋０．５）；梯度洗脱；ＵＶ２５４ｎｍ、２９０ｎｍ、３６０ｎｍ同时测定。线性范围为０．１～１０μｇ，各种维生素的ＲＳＤ在１．２％～３．０％之间（ＶｉｔａｍｉｎＢ１２除外），回收率大于９０％。     

脱乙酰壳多糖化学修饰电极测定铂的研究

用脱乙酰壳多糖修饰电极为工作电极，阳极溶出伏安法测定痕量铂。在ｐＨ＝２￣３的ＫＣｌ－ＨＣｌ底液中，－０．３Ｖ富集２ｍｉｎ，静止１５ｓ，以０．２Ｖ／ｓ扫速阳极溶出，峰电位在－０．１６Ｖ（ｖｓ．ＳＣＥ），铂（Ⅳ）离子浓度在０．５￣５．０μｇ／ｍＬ范围内与峰高呈线性关系。富集１０ｍｉｎ后，可检测０．０２５μｇ／ｍＬ铂（Ⅳ）。该法用于贵金属矿样的测定，无需分离，结果满意。用循环伏安法、紫外光谱和拉曼光谱研     

流动注射在线柱预富集—电感耦合等离子体原子发射光谱测定痕量…

本文报道了流动注射在线柱预富集ＩＣＰ光谱测定痕量金属的方法，以ｍｅｓｏ－四（４－磺基苯）卟啉为柱前衍生试剂，硅胶作固定相和盐酸作洗脱液，对痕量金属离子Ｃｕ、Ｍｎ、Ｎｉ、Ｆｅ、Ｐｂ、Ｃｄ进行在线预富集检测。在给定实验条件下，方法的富集倍数为９．３～１１．３，检出限和测定的相对标准偏差（ｎ＝６）分别在０．３２～２６．８ｎｇ／ｍｌ和１．３％～３．０％范围内。方法用于小牛肝和西红柿叶样品分析，结果与参考值     

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%.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.