铽-沙拉沙星荧光光度法测定沙拉沙星含量

在pH 5.9醋酸-醋酸钠缓冲溶液中,Tb3+与沙拉沙星反应形成1:2的稳定络合物,发出Tb3+特征荧光.Tb3+在激发波长335 nm,发射波长545 nm处的特征荧光强度与沙拉沙星含量成正比,沙拉沙星溶液浓度在0.05～0.65 mg/L范围内符合线性关系,方法检出限为0.72μg/L.该方法用于片剂中盐酸沙拉沙星含量的测定,6次平行测定该方法回收率为94.8%～104.3%,相对标准偏差为1.5%～3.8%.     

曙红分光光度法测定沙拉沙星

在pH 3.0的Clark-Lubs缓冲溶液存在下,盐酸沙拉沙星溶液在可见光区无吸收,当将其加入曙红溶液中,发现曙红吸收峰有明显位移,且吸光度增加,说明盐酸沙拉沙星与曙红反应生成络合物。盐酸沙拉沙星在4.0-220.0mg/L的范围内与吸光度呈良好的线性关系,方法检出限为117.6μg/L。用于片剂中盐酸沙拉沙星的测定,6次平行测定相对标准偏差为1.4%-3.9%,回收率为92.8%-105.8%。     

高效液相色谱同时测定鸡蛋中4种氟喹诺酮类药物残留

建立了固相萃取—反相高效液相色谱同时分析鸡蛋样品中4种氟喹诺酮类药物残留量的方法。对鸡蛋样品的提取及其在C18固相萃取柱上的净化条件进行了研究,采用高效液相色谱分离,荧光检测器检测(λex=280nm,λem=450nm),外标法定量。4种沙星标准曲线的线性回归系数均在0．9999以上,环丙沙星、恩诺沙星、沙拉沙星的线性范围为2．5～500μg／L;达诺沙星为0．5～100μg/L。鸡蛋样品中4种沙星的加标回收率为78．1％～95．7％;相对标准偏差为4．1％～16．2％。环丙沙星、恩诺沙星、沙拉沙星的最低检出限为10μg／kg;达诺沙星的最低检出限为2μg/kg。     

荧光偏振免疫分析方法快速检测沙拉沙星残留

以异硫氰酸荧光素(FITC)标记沙拉沙星合成荧光标记物,采用薄层色谱法提纯,优化了反应时间、标记物和抗体的工作浓度,建立了沙拉沙星的快速荧光偏振免疫分析法( FPIA).本方法测定沙拉沙星在缓冲液中的半数抑制浓度(IC50)为43.2 μg/L;检测范围为5.7～327 μg/L,可以达到国家规定的动物性食品中兽药最高残留限量(80 μg/kg)的要求.本研究考察了FPIA测定沙拉沙星的动力学过程及对其它4种喹诺酮类药物的交叉反应.结果表明,环丙沙星、恩诺沙星、加替沙星及氧氟沙星的交叉反应率分别为3.3％,1.8％,1.7％和0.7％.在牛奶和猪尿中沙拉沙星的回收率分别在71％～94％和74％～102％之间.本方法操作简单快捷,整个检测过程只需5 min、而且灵敏度较高、特异性强,适用于动物性食品中沙拉沙星残留的快速筛选检测.     

四溴荧光素荧光猝灭法测定司帕沙星

基于司帕沙星能够猝灭四溴荧光素的荧光且荧光猝灭程度与司帕沙星的量成正比,建立了一种测定微量司帕沙星的方法。在pH3．5的Clark—Lubs缓冲溶液中,四溴荧光素激发波长λex=485nm、发射波长λem=545nm,司帕沙星的质量浓度在0～2．0mg／L范围内符合比耳定律,方法检出限为42．7μg/L。已用于片剂及胶囊中司帕沙星的测定。6次平行测定回收率为93．8％～104．3％,相对标准偏差为1．1％～2．8％。     

反相离子对液相色谱法同时测定11种氟喹诺酮类药物的研究

建立了高效液相色谱-荧光法同时测定11种氟喹诺酮类药物的分析方法.主要研究了流动相、流动相配比及流动相的pH对氟喹诺酮分离的影响.确定了液相色谱分析最佳条件.分离条件为:Xbridge Shield RP C18柱,以V(0.10%三氟乙酸)∶V(乙腈)∶V(甲醇)=89∶4∶7为流动相;检测波长为λex=280 nm和λem＝450 nm.方法检出限为:诺氟沙星、环丙沙星、培氟沙星和恩诺沙星0.007μg/mL,单诺沙星0.002 μg/mL,沙拉沙星和氧氟沙星为0.04 μg/mL,二氟沙星和奥比沙星为0.02 μg/mL,依诺沙星、麻保沙星为0.4 μg/mL,各组分回收率在97%～100.2%,相对标准偏差为0.2%～2.9%.     

荧光光度法测定环境水样中的苯酚和对苯二酚

建立了荧光光度法直接测定环境水样中的苯酚和对苯二酚的新方法.通过β-环糊精增敏,三维荧光扫描选择测量波长,在波长对为λex/λem=273/307 nm时测定苯酚,苯酚的线性范围为0～1×10-4 mol/L,检出限为6.6×10-8 mol/L;在波长对为λex/λem=295/331 nm时测定对苯二酚, 对苯二酚的线性范围为0～1.5×10-5 mol/L,检出限为5.2×10-9 mol/L,回收率达到93.5%～103.5%.     

高灵敏度荧光增敏法测定头孢氨苄

在盐酸介质中,基于痕量头孢氨苄(CPX)对β-环糊精(β-CD)增敏KBrO3-KBr氧化亚甲蓝(MB)体系的荧光具有增强作用,提出了一种新的测定头孢氨苄荧光分析方法。该体系最大激发波长为λex=660 nm,最大发射波长为λem=678 nm,线性范围为0.001～3.5 mg/L,检出限为0.0002 mg/L,相对标准偏差为1.3%。方法可作为痕量头孢氨苄的分析方法。     

流动注射化学发光法测定兽药制剂中沙拉沙星

基于沙拉沙星对Ag(III)络合物-H2SO4体系化学发光信号的增敏作用,提出了一种流动注射-化学发光测定沙拉沙星的新方法。考察和优化了影响化学发光强度的条件。沙拉沙星在2.0×10-7～1.0×10-5g/mL范围内,其校准曲线具有良好的线性。方法的检出限为1.2×10-7g/mL,相对标准偏差0.5%～1.2%。该方法已用于沙拉沙星兽药制剂的质量检测,回收率为83.3%～96.3%。通过比较其荧光光谱和化学发光光谱,讨论了该体系的化学发光机理。     

等色吸收荧光猝灭法快速测定食品中苏丹红Ⅰ

在乙醇介质中, 强荧光染料吖啶的荧光波长478 nm与苏丹红Ⅰ的吸收光波长480 nm十分接近, 由于等色性苏丹红Ⅰ能够有效吸收吖啶发出的荧光, 使吖啶在激发波长λex=410 nm、荧光波长λem=478 nm处荧光猝灭, 依此建立了荧光猝灭测定苏丹红Ⅰ的新方法. 该方法快速、简便, 其线性范围为3.72～37.2 mg/L, 方法检出限为1.1 mg/L. 用于辣椒、辣椒酱食品中痕量苏丹红Ⅰ的测定. 6次平行测定, 相对标准偏差为0.8%～2.7%, 加标回收率为89.5%～104.0%.     

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%.     

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.     

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.     

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.     

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.     

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.