高效液相色谱-电喷雾离子阱质谱法分析6种氨基糖甙类抗生素

采用高效液相色谱-电喷雾离子阱质谱(HPLC-MSn)联用,分离和鉴定6种氨基糖甙类抗生素及其中的杂质,并探讨这6种结构相似的氨基糖甙类抗生素的质谱裂解规律。采用Agilent SB-C18(250 mm×4.6mm,5μm)色谱柱,流动相为0.05mol/L三氟乙酸溶液-甲醇(90∶10)和0.05 mol/L五氟丙酸溶液-甲醇(65∶35);在正离子检测方式下,用电喷雾离子阱质谱法对阿司米星、异帕米星、大观霉素、威替米星、奈替米星、西索米星及其杂质进行多级质谱分析。异帕米星、威替米星、奈替米星、西索米星及其杂质在二级质谱分析时,均可发生B环(脱氧链霉胺)与C环(氨基葡萄糖)之间的糖苷键断裂,生成脱去C环的碎片离子,并进一步发生A环(氨基葡萄糖)与B环之间的糖苷键断裂,生成A环或B环的碎片离子。鉴定了6种氨基糖甙类抗生素中7个杂质的结构。     

高效液相色谱-电喷雾-离子阱质谱法推定硫酸依替米星中有关物质的结构

采用高效液相色谱-电喷雾-离子阱质谱法(HPLC-ESI-IT-MSn)对硫酸依替米星中有关物质结构进行推定.采用Phenomnex Gemini NX C18色谱柱,以水-氨水-冰醋酸(96∶ 3.6∶ 0.4, V/V)-甲醇(70∶ 30, V/V)为流动相,质谱条件:电喷雾离子源(ESI),正离子检测模式;离子源温度350 ℃;雾化氮气压力275.8 kPa;干燥氮气流速10 L/min;离子阱质谱检测器,Smart扫描模式,扫描质量范围m/z 100～900.硫酸依替米星样品中共检出18种有关物质,对其中的13种物质的结构进行了推定,其余5种有关物质的结构未进行解析,只提供了分子量和二级质谱信息.     

高效液相色谱-电喷雾质谱(HPLC-ESI-MS/MS)测定新型抗癌铂配合物

采用高效液相色谱-电喷雾-多级质谱法(HPLC-ESI-MS/MS), 研究了cis-3,5-diisopropylsalylic cyclohexanodiaminoplatinum(Ⅱ)的电喷雾质谱行为, 鉴定了其杂质, 并测定了其纯度.     

高效液相色谱-离子阱-飞行时间质谱法鉴定碱性嫩黄中的杂质及高效液相色谱法制备碱性嫩黄标准物质

该文建立了一种高效液相色谱-离子阱-飞行时间质谱（HPLC-IT-TOF-MS）分析非法食品添加剂碱性嫩黄样品中杂质成分的方法。对碱性嫩黄样品中的杂质进行多级质谱分析,根据各碎片离子的精确质量数推测出该杂质的具体组成,确定这个杂质为4-（亚氨基（4-（甲基氨基）苯基）甲基）-N,N-二甲基苯胺盐酸盐,从而推断出碱性嫩黄的合成方法及杂质的可能来源。同时建立了制备碱性嫩黄标准物质的方法,分别选用了粒径为10μm和5μm的制备液相色谱柱进行两次制备高效液相色谱分离纯化,进样量分别为1 mL和500μL,最终采用分析型高效液相色谱峰面积归一化法得到纯度为99.52%的碱性嫩黄标准物质。扣除0.34%水分含量,0.13%灰分含量,采用质量平衡法确定制备的物质最终纯度为99.05%,并通过UV、IR、LC-MS和NMR四大谱图进行化学结构的确认。该方法简单、高效,可拓展应用于其他非法食品添加剂标准物质的制备。     

黄连生物碱的反相高效液相-电喷雾离子阱串联质谱的研究

采用反相高效液相-电喷雾离子阱串联质谱法对由乙醇提取的黄连生物碱进行了研究.优化出了反相高效液相色谱分离黄连生物碱的条件:流动相为V(乙腈):V(H2O)(三乙胺2 mmol/L)=30:70;柱温为30℃;流速为0.5 mL/min,并结合电喷雾串联质谱检测出了黄连生物碱中的小檗碱、药根碱、巴马汀、黄连碱以及微量的表...     

基于纳升电喷雾-便携式离子阱质谱的苯扎氯铵快检方法

采用纳升电喷雾源(Nano-ESI)-便携式离子阱质谱(Portable Ion Trap MS)建立了滴眼液杀菌成分苯扎氯铵(BAC)的快速检测方法。在正离子模式下,将滴眼液样品稀释后注入纳升电喷雾源的毛细管,毛细管出口与离子阱质谱进样口距离为10 mm、喷雾电压为2000 V;毛细管电压,毛细管温度和离子漏斗电压分别设为5 V,30℃和40 V。用3种苯扎氯铵的[M-Cl]+峰作为定性判据;用纯物质配制溶液制作定量分析校准曲线。3种苯扎氯铵校准曲线的线性范围1～500 mg/L,相关性系数(R2 0.99);用11次空白样品测试结果评估方法检出限和定量限为0.1,0.33 mg/L,满足限量判定要求。4种实际样品中3类BAC的定量测定结果同高效液相色谱-质谱法无显著性差异。该方法无需联用色谱,分析时间仅为2 min,可应用于滴眼液等保健品中添加剂苯扎氯铵的快速筛查。     

高效液相色谱-质谱法快速鉴定复方毛冬青冲剂中三萜皂苷活性成分

建立了高效液相色谱-质谱法(HPLC-MS)快速鉴定复方毛冬青冲剂中三萜皂苷活性成分的方法.以甲醇为萃取剂超声萃取复方毛冬青冲剂30 min.采用高效液相色谱-离子阱质谱(HPLC-IT-MS)和高效液相色谱-飞行时间质谱(HPLC-TOF-MS)对萃取液进行分析,选用Agilent Zorbax Eclipse XDB C18色谱柱(250 mm×4.6 mm, 5 μm),以水(含0.1 %甲酸)-乙腈为流动相进行梯度洗脱,柱后流出液采用电喷雾离子阱质谱(ESI-IT-MS)和电喷雾飞行时间质谱(ESI-TOF-MS)的正、负离子模式进行检测.检测结果经离子阱一级质谱(IT-MS1)、离子阱二级质谱(IT-MS2)和分析时间质谱(TOF-MS)信息分析,并与相关文献报道进行比较,鉴定出1种三萜酸和8种三萜皂苷成分,并推测了其它3种可能的三萜皂苷化学成分,通过对照品对比分析,三萜酸确证为Ilexgenin A,其中一种三萜皂苷确证为Ilexsaponin A1.本方法无需对照品即可快速有效地鉴定出复方毛冬青冲剂中的三萜皂苷活性成分,为建立冲剂的质量标准提供了依据.     

高效液相色谱-质谱法对饲料及食品添加剂中三聚氰胺的测定

建立了饲料中三聚氰胺的高效液相色谱-质谱测定方法.色谱条件:Kromasil C18柱(4.6 mm×250mm,5 μm),流动相:乙腈-0.1%(体积分数)甲酸(体积比5:95),流速0.4 mL/min.采用正离子模式的电喷雾质谱检测,以一级质谱得到的准分子离子m/z 127作为母离子,进行碰撞诱导解离(CID)二级质谱(MS2)分析,选择母离子和MS2的碎片离子m/z 85、109定性确证,提取m/z 85、109、127三个离子质量色谱峰面积定量.实验优化了质谱条件.线性范围为0.01～0.5 mg/L,检出限0.01 mg/L(S/N=3),回收率为80%～99%.     

高效液相色谱-离子阱/飞行时间质谱鉴定违禁药品邻氯苯基环戊酮中杂质及其标准物质的制备（英文）

建立了高效液相色谱-离子阱/飞行时间质谱(HPLC-IT/TOF MS)分析违禁药品邻氯苯基环戊酮样品中杂质成分的方法。对邻氯苯基环戊酮标准品进行多级质谱分析,根据各碎片离子的精确质量数推测邻氯苯基环戊酮的裂解路径,并利用该方法检测出邻氯苯基环戊酮样品中的2种杂质成分:2-氯苯甲酸酸酐和1,2-二邻氯苯甲酰基环戊烯,推断出该违禁药品的合成方法,为追溯其来源提供了重要依据。同时建立了制备邻氯苯基环戊酮标准品的方法,制备高效液相色谱条件是流动相甲醇-水(85∶15,v/v),流速8 mL/min,进样量1 mL。制备得到的邻氯苯基环戊酮标准物质纯度为99.53%。该方法简单、高效,可拓展应用于其他违禁药物标准物质的制备。     

高效液相色谱-柱后衍生和质谱联用测定大米中氨基甲酸酯类农药残留量

研究了高效液相色谱-柱后衍生荧光检测和液质联用分别测定大米中14种和16种氨基甲酸酯类农药残留量的方法.二氯甲烷和丙酮的混和溶剂提取后,用柱后衍生荧光检测法和离子阱多级质谱联用法进行测定.柱后衍生荧光检测法检出限为20～50 μg/kg,离子阱多级质谱联用法检出限为10～20 μg/kg,添加平均回收率在70%～92%之间,RSD%在6.7%～12%.     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Hard and soft acids and bases: structure and process

Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.