毛细管电泳法快速测定保健食品中免疫球蛋白G

建立了毛细管电泳法快速测定保健食品中免疫球蛋白G(IgG)含量的方法,成功测定了不同剂型(片剂、粉剂及胶囊)牛初乳保健品中IgG的含量。以37 cm×50μm(i.d.)未涂敷熔融石英毛细管为色谱分离柱,50 mmol/L四硼酸钾 65 g/L聚乙二醇20 000(1 mol/L氢氧化铯调pH 10.0)为运行缓冲液,于214 nm波长处检测。详细研究了影响实际样品中IgG分离及准确定量的关键因素,如添加剂的种类、浓度;运行及样品缓冲液的浓度及pH等。采用峰面积外标法定量。方法的精密度为2.1%(n=7);检出限为6.25 mg/L(S/N=3);线性范围为50~2000 mg/L;400 mg/L IgG迁移时间的相对标准偏差(RSD)为0.14%;峰面积的RSD为2.9%(n=7)。6 m in内即可实现保健食品中IgG的分离与测定,结果与产品标示值基本吻合。     

元胡中延胡索乙素的离子液体-毛细管电泳法测定

建立了以离子液体为电解质,测定元胡药材中延胡索乙素含量的毛细管电泳新方法.探讨了离子液体浓度、pH值、分离电压对分离效果的影响以及分离的机理.在以石英毛细管为分离柱,50 mmol/L 1-丁基-3-甲基咪唑四氟硼酸盐(pH 7.1)为电泳介质,分离电压20 kV的条件下,延胡索乙素可与其它组分在5 min内完全分离.延胡索乙素的线性范围为31.25 ～500 mg/L,检出限为4.86 mg/L,回收率为95% ～102%.     

微乳毛细管电泳法测定脑心通胶囊中4种有效成分

建立了一种微乳毛细管电泳法同时检测脑心通胶囊中芍药苷、阿魏酸、丹酚酸B和丹参酮ⅡA 4种有效成分的含量。使用未涂层熔融石英毛细管(60cm×75μm i.d.,有效长度50cm)为分离通道,以50mmol/L十二烷基硫酸钠(SDS)-60mmol/LTris(含8.3%正丁醇,1.3%正己烷和15%乙腈,pH=8.8)作电解质,于230nm波长下进行检测。芍药苷、阿魏酸、丹酚酸B和丹参酮ⅡA的质量浓度分别在10～300mg/L、2.5～80mg/L、10～100mg/L和5.0～80mg/L范围与其峰面积呈良好的线性关系,4种物质的检出限分别为1.5mg/L、0.5mg/L、2.0mg/L和1.0mg/L。样品加标回收率在92%～105%之间,相对标准偏差均小于3.2%。方法简便、快速,已用于实际样品的分析。     

一种基于二喹啉甲酸- Cu+显色反应的毛细管电泳检测蛋白质的新方法

采用毛细管电泳法和蛋白质显色反应-二喹啉甲酸(BCA)法,结合微波辅助反应,在60 mmol/L硼酸盐缓冲液(pH 9.5)中,实现了对蛋白质的快速毛细管电泳分析检测。同时以β-环糊精为包合添加剂,实现了BCA-Cu+复合物和游离BCA的分离,从而在波长200 nm处以测定特征生成的BCA-Cu+复合物来间接检测蛋白质,其峰强度比直接检测蛋白质自身吸收的峰强度提高了2个数量级。对于转铁蛋白、蓖麻毒素,其线性范围分别为2～200 mg/L和2～100 mg/L,检出限分别为0.33和0.37 mg/L。将该方法成功地应用于第一届蓖麻毒素国际实验室间比对测试的部分样品,含量测定结果满意。     

胶束电动毛细管色谱测定塑料食品包装袋中邻苯二甲酸酯类化合物的研究

采用胶束电动毛细管色谱法对5种邻苯二甲酸酯类化合物(邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP))和邻苯二甲酸二正辛酯(DOP))进行了分离研究,考察了溶液的pH值、胶束浓度和有机改性剂等对分离的影响。结果表明:以5 mmol/L硼砂-25 mmol/L十二烷基硫酸钠(SDS)-15%(体积分数)甲醇溶液为电泳缓冲液(pH 9.2),采用压力进样方式,25 kV恒压下进行分离,在波长200 nm处检测,各组分在17 min内可达到基线分离。DMP、DEP、DBP、DEHP和DOP的检出限分别为0.13 mg/L、0.14 mg/L、0.38 mg/L0、.13 mg/L和0.10 mg/L。本法应用于塑料食品袋中邻苯二甲酸酯类化合物的测定,回收率范围为81.80%~118.87%,峰面积的相对标准偏差(RSD)小于4.30%(n=10),测定结果满意。     

在线扫集-胶束毛细管电动色谱法测定扛板归中的阿魏酸、咖啡酸和原儿茶酸

采用在线扫集-胶束毛细管电动色谱法(sweeping-MEKC)分离测定扛板归中的阿魏酸、咖啡酸和原儿茶酸。采用未涂层熔融石英毛细管(50 cm×50μm,有效柱长36 cm);环境温度25℃;缓冲体系为20 mmol/L NaH2PO4-80mmol/L十二烷基磺酸钠(SDS)-12.5%乙腈(V/V)(pH 2.20),紫外检测波长为216 nm,运行分离电压-20 kV,进样时间100 s。在优化条件下,3种有机酸均在20 min内出峰,峰面积RSD均小于5%。检出限分别达到98.52,118.73和27.27μg/L。     

胶束毛细管电泳在线扫集技术同时分离测定穿心莲内酯和脱水穿心莲内酯的研究

采用胶束毛细管电泳在线扫集技术分离测定了中药穿心莲中脱水穿心莲内酯和穿心莲内酯.电泳条件:以20 mmol/L H3BO310 mmol/L NaH2PO4-50mmol/L SDS(含体积分数20%甲醇,pH 2.4)为电泳运行缓冲溶液,未涂层石英毛细管(58 cm×50 μm i.d.,有效长度为41.2 cm)为分离通道,重力进样,进样高度为11 cm,-20 kV恒压,检测波长为246 nm.富集倍数可以达到200倍以上.在5.70～91.20 mg/L,和3.96～31.68 mg/L范围内呈良好的线性关系,对两种内酯分别进行了定量分析.加标平均回收率脱水穿心莲内酯为100.80%,穿心莲内酯为98.06%.     

毛细管电泳柱上络合分离、间接紫外检测重金属离子

采用弱络合剂乙醇酸,柱上络合,间接紫外检测毛细管区带电泳(CZE)技术对重金属离子Ba2+、Cr3+、Cd2+、Pb2+及可能存在的干扰离子进行了分离研究。通过对背景电解质种类和浓度、缓冲液pH、有机添加剂等的优化,确定了最佳分离体系为含12 mmol/L络合剂乙醇酸的10 mmol/L吡啶溶液作为背景电解质(pH 4.0)。在电压15 kV,压差进样68.95 kPa.s,260 nm间接紫外检测条件下,采用50 cm(45.5 cm)×50μm(I.D.)石英毛细管,重复性实验(n=9):迁移时间RSD≤1.37%,峰高RSD≤1.70%,峰面积RSD≤3.55%;Pb2+、Ba2+和Cd3+的检出限(S/N=3)为0.2 mg/L,Cr3+的检出限为0.08 mg/L;在检出限至10 mg/L范围内,各离子的浓度与峰面积线性相关系数好于0.998。该方法并应用于实际样品的分析。     

毛细管区带电泳分离西孟坦对映异构体

以β-CD为手性选择剂,采用毛细管区带电泳成功分离了西孟坦对映异构体。考察了背景电解质中硼砂缓冲液的pH和浓度、β-CD浓度、有机添加剂甲醇含量及分离电压对手性分离的影响,建立了毛细管电泳分离西孟坦对映异构体的方法。最佳分离条件为：20mmol／L硼砂缓冲液(pH11．0,含12mmol／Lβ-CD)-甲醇(50：50,V/V);分离电压20kV。在此条件下西孟坦对映异构体可达基线分离。在25～50mg／L范围内,迁移时间的重复性(RSD)控制在1．9％之内,峰面积重复性的RSD小于4．0％,本方法可用于西孟坦对映异构体的手性分离和定量分析。     

胶束电动毛细管色谱-间接紫外检测法测定糖蜜酒精废液中的有机酸

建立了一种利用胶束电动毛细管色谱-间接紫外检测法同时测定丙二酸、甲酸、酒石酸、苹果酸、琥珀酸、戊二酸、乙酸、乳酸和谷氨酸的新方法。以7.5 mmol/L邻苯二甲酸氢钾-1.5 mmol/L十六烷基三甲基溴化铵(用0.1 mol/L氢氧化钠调pH至6.50)混合液作为电泳介质,检测波长为300 nm,参比波长为210 nm,未涂层弹性石英毛细管(50 μm i.d.×64 cm)为分离通道,在6 min内实现了9种酸的完全分离。9种有机酸的浓度与其峰面积在一定的范围呈良好的线性关系,检出限均低于1.5 mg/L,迁移时间和峰面积的日内、日间相对标准偏差均小于6%。该法用于糖蜜酒精废液中有机酸的测定,结果令人满意,9种有机酸的样品加标回收率均在93%以上。     

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.     

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.     

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.     

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.