灿烂甲酚蓝二聚体作为荧光探针测定人血清白蛋白

阳离子染料灿烂甲酚蓝(BCB)在适宜浓度的阴离子表面活性剂十二烷基硫酸钠(SDS)或十二烷基磺酸钠(SLS)存在时形成二聚体。研究了以此形成的现场二聚体作为荧光探针测定蛋白质的可能性。结果表明,二聚体具有弱荧光,其荧光强度的回升与体系中蛋白质的量呈线性关系,线性范围为0～7.8μg·ml-1,检出限为3.89×10-3μg·ml-1。用于人血清白蛋白的测定,结果满意。     

一阶导数吸光光度法测定碘酸钾碘盐中碘

采用一阶导数吸光光度法测定碘酸钾碘盐中碘 ,线性范围为 0～ 12 μg·ml-1,检出限为1.6μg·ml-1,对盐样进行重复测定 ,相对标准偏差≤ 1.9% ,对样品进行加标回收试验 ,回收率在 97.0 %～ 10 2 .5 % ,结果良好     

火焰原子吸收光谱法连续测定番木瓜中铜锌铁锰

探讨了用微波消化罐消化样品、用火焰原子吸收光谱法在同一体系中测定番木瓜中微量元素铜、锌、铁、锰的方法。在微波消化罐内用硝酸和过氧化氢消化样品 ,具有试剂用量少免受污染、消化时间短等优点。考察了硝酸、过氧化氢用量以及消化时间的影响 ,以及在同一体系中铜、锌、铁、锰的干扰情况。在选定条件下 ,铜检出限为 0 .0 0 4 μg·ml- 1,锌检出限为 0 .0 0 4 8μg·ml- 1,铁检出限为 0 .0 0 3μg·ml- 1,锰检出限为 0 .0 0 6 μg·ml- 1,相对标准偏差为 1.7%～ 4 .9% ,回收率为 96 .8%～ 10 6 .6 %。方法具有简便、省时、准确、可靠的优点     

谷氨酸流动注射化学发光法测定

在碱性介质中,谷氨酸对硫氰化钾 鲁米诺化学发光体系有增敏作用,建立了用硫氰化钾 鲁米诺 氨基酸体系测定谷氨酸的新方法。该法灵敏度高,操作简单、快速。用该方法测定谷氨酸的线性范围为0.01～1.0μg·ml-1,检出限可达0.01μg·ml-1,采样频率为190次·h-1,对5μg·ml-1的谷氨酸连续平行测量10次,RSD为1.2%。用该方法对皮革屑中酶法提取的谷氨酸含量进行了测定,并与氨基酸测定仪测定的结果进行了比较,结果满意。     

NBSM-荧光素体系流动注射化学发光法测定盐酸二甲双胍

在碱性条件下,N 溴代丁二酰亚胺(NBSM)氧化盐酸二甲双胍,体系中荧光素作为能量转移剂,在十六烷基三甲基溴化铵(CTMAB)的增敏作用下产生化学发光。基于此,结合流动注射技术,首次建立了测定盐酸二甲双胍的化学发光分析法,详细研究了影响化学发光强度的因素,并探讨了化学发光可能的机理。化学发光信号的增加值ΔI与盐酸二甲双胍浓度在7×10-8～1×10-5g·ml-1范围内呈线性关系,方法的检出限(3σ)为2.4×10-8g·ml-1,对9×10-8g·ml-1盐酸二甲双胍进行了11次平行测定,相对标准偏差为3.8%。将方法用于盐酸二甲双胍片剂中盐酸二甲双胍的定量分析,结果满意。     

半微分极谱法连续测定食物中锌铁锰和铜

研完了用1.5次微分极谱法,在乙二胺-8-羟基喹咻系列底液中,连续测定食物中锌、铁、锰和铜的方法。在选定的试验条件下．锌、铁和锰的浓度在0.02～4.0μg·ml-1、的浓度在0.02～1.0μg·ml-1范围内与峰高呈线性关系。样品测定的相对标准偏差为4.7%～10.0%,回收率为92.5%～106.0%。对食物样品分析的结果与电感耦合高频等离子体发射光谱法(ICP)比较,没有显著性差异。     

焙烧富集分离-硒化氢发生原子荧光光谱法测定纯锑中微量硒

研究了一种焙烧富集分离 硒化氢发生原子荧光光谱法测定纯锑中微量硒的方法。在选定的试验条件下 ,方法检出限为 0 .0 1μg·g- 1,线性范围为 0 .0 0 1μg·ml- 1～ 0 .3μg·ml- 1,加标回收率为 94 %～ 99%。用此法测定了 5个纯锑参考样中微量硒 ,结果与参考值一致。     

壳聚糖修饰铂电极半微分伏安法测定微量碘

将壳聚糖修饰到铂盘电极上,采取半微分伏安法测定微量碘。用0.20mol·L-1NaH2PO4 Na2HPO4(pH6.0)缓冲体系,在0.20～0.65V间以10mV·s-1的速度扫描,碘离子浓度在0.80～25.0μg·ml-1范围内与氧化峰电流呈线性关系(r=0.9996),检出限达0 20μg·ml-1。修饰电极在4.0μg·ml-1KI溶液中,11次测得峰电流的相对标准偏差为3.3%。将该修饰电极用于华素片中微量碘的测定,与间接火焰原子吸收光谱法相比,相对误差在5%以内。     

间接原子吸收光谱法测定工业废水中痕量二硫化碳

研完了用二硫代氨基甲酸银间接原子吸收光谱法测定工业废水中二硫化碳。线性范围为2～30μg·ml-1,检出限为1.02μg·ml-1,回收率为96%～106％;且H2S和Cu(Ⅱ)等不干扰测定。方法适用于工业废水中二硫化碳的测定,结果满意。     

催化光度法测定痕量甲醛

基于磷酸介质中甲醛催化溴酸钾氧化溴甲酚紫的褪色反应 ,建立了测定痕量甲醛的方法。方法的检出限为 1.0× 10 - 5g·L- 1,线性范围为 0 .0 2 0～ 0 .4 8μg·ml- 1,方法简便 ,用于空气中测定痕量甲醛 ,结果满意。     

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.     

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.     

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.