固相萃取/高效液相色谱法同时测定保健食品中7种磺酰脲类降血糖药物

建立了同时测定保健食品中7种磺酰脲类降血糖药物(格列吡嗪、甲苯磺丁脲、妥拉磺脲、格列齐特、格列本脲、格列美脲和格列喹酮)的固相萃取/高效液相色谱(SPE/HPLC)分析方法。样品经甲醇超声提取,用C18固相萃取柱净化后进行HPLC分析。采用Agilent Zorbax SB-C18色谱柱(250 mm×4.6 mm,5μm),以乙腈(A)-0.02%磷酸溶液(B)为流动相,梯度洗脱,流速1.0 mL/min,柱温30℃,检测波长228 nm。结果表明,7种目标物在0.2~20μg/mL范围内线性关系良好,相关系数(r)大于0.999 9,检出限(LOD,S/N≥3)均为0.1 mg/kg,在5种不同基质中的加标回收率为81%~115%,相对标准偏差(RSD)小于9%。     

超高效液相色谱-串联质谱法同时测定指纹中的4种磺酰脲类降糖药北大核心CSCD

分别使用棉签、滤纸采取指纹后,将棉签头剪下、滤纸剪碎,分别置于1.5mL塑料离心管,分别加入0.25,0.50mL甲醇,超声振荡3min,离心3min,上清液经0.22μm滤膜过滤后,采用ACQUITY UPLC HSS C18色谱柱(2.1mm×50mm,1.8μm)分离指纹中的格列本脲、格列美脲、格列吡嗪和格列齐,以乙腈-0.1%(φ)甲酸溶液为流动相进行梯度洗脱,质谱分析中采用电喷雾正离子源和多反应监测模式。4种磺酰脲类降糖药线性范围为0.25~250ng/swab(patch),检出限(3S/N)为0.125ng/swab(patch)。加标回收率在68.0%~123%之间,测定值的相对标准偏差(n=5)在1.2%~9.5%之间。     

超高效液相色谱-串联质谱法同时测定指纹中的4种磺酰脲类降糖药

分别使用棉签、滤纸采取指纹后,将棉签头剪下、滤纸剪碎,分别置于1.5mL塑料离心管,分别加入0.25,0.50mL甲醇,超声振荡3min,离心3min,上清液经0.22μm滤膜过滤后,采用ACQUITY UPLC HSS C18色谱柱(2.1mm×50mm,1.8μm)分离指纹中的格列本脲、格列美脲、格列吡嗪和格列齐,以乙腈-0.1%(φ)甲酸溶液为流动相进行梯度洗脱,质谱分析中采用电喷雾正离子源和多反应监测模式。4种磺酰脲类降糖药线性范围为0.25~250ng/swab(patch),检出限(3S/N)为0.125ng/swab(patch)。加标回收率在68.0%~123%之间,测定值的相对标准偏差(n=5)在1.2%~9.5%之间。     

超高效液相色谱-串联质谱法检测血液斑痕中磺酰脲类降糖药

建立了血液斑痕中格列本脲,格列美脲,格列吡嗪的液相色谱-质谱检验法。选用ACQUITY UPLC HSS C18(2.1×50 mm,1.8μm)色谱柱,使用0.1%甲酸水-乙腈体系作为流动相进行梯度洗脱。采用ESI+电喷雾离子源,多反应监测扫描模式(MRM)检测3种磺酰脲类降糖药。在最优条件下,磺酰脲类降糖药在1.25~250 ng/patch(swab)范围内有良好线性关系,保留时间依次为2.90,3.00,2.34 min。检出限为0.1 ng/mL。渗透性客体上药物的回收率随着浓度的增大而增大,非渗透性客体上药物的回收率随着浓度的增大而减小。日内与日间精密度均小于15%,基质效应在0.85~1.15之间。可用于血液斑痕中格列本脲,格列美脲,格列吡嗪的快速筛查。     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速筛查及定量分析保健品中11种非法添加降糖药物

基于超高效液相色谱-四极杆/静电场轨道阱质谱建立了保健品中11种非法添加化学降糖药(那格列奈、盐酸吡格列酮、格列喹酮、格列齐特、格列吡嗪、格列本脲、盐酸二甲双胍、瑞格列奈、盐酸苯乙双胍、盐酸罗格列酮、格列美脲)的快速筛查和定量分析方法。样品采用甲醇提取,C18色谱柱(100 mm×4.6 mm, 2.7 μm)分离,用10 mmol/L乙酸铵水溶液和乙腈进行梯度洗脱,正离子模式扫描。化合物一级质谱的分辨率为70000,二级质谱分辨率为17500。实验结果表明,11种化合物在0.005~0.5 mg/L范围内具有良好的线性(线性相关系数均大于0.99),各降糖类药物检出限为2.7~5.1 μg/kg,回收率为87.3%~98.3%,相对标准偏差为2.18%~5.21%。本方法具有准确、简便、快速的特点,可用于降糖类保健品中11种降糖药物的定性筛查和定量分析。     

分子印迹复合膜对降糖药的拉曼光谱快速检测

基于分子印迹技术的特异性识别特点, 以假模板盐酸胍和4-(2-氨乙基)苯磺酰胺制备了2种分子印迹复合膜, 用其对保健品中的二甲双胍、 苯乙双胍和格列本脲进行吸附后, 采用拉曼光谱法实现了保健品中降糖药的富集与快速检测. 考察了膜制备过程中纳米银的加入对拉曼光谱的增强作用, 以及吸附样品浓度等的影响. 实验结果表明, 盐酸胍分子印迹复合膜吸附5 mg/mL以上的二甲双胍或苯乙双胍后具有明显的拉曼响应, 4-(2-氨乙基)苯磺酰胺印迹膜吸附10 mg/mL格列本脲后具有明显的拉曼响应. 所建立的分子印迹复合膜结合拉曼光谱检测方法可用于多种实际样品的检测.     

高效液相色谱法测定人血清中格列吡嗪浓度

建立了人血清中格列吡嗪浓度的HPLC测定方法, 为研究格列吡嗪的代谢动力学及相对生物利用度提供了方法. 采用Oasis HLB萃取小柱对血清样品进行处理, 格列齐特为内标, C18为固定相. 流动相为V(乙腈)∶V(0.08%三乙胺)＝40∶60水溶液;H3PO4 调节pH为3.5, 流速1.0 mL/min, 柱温30 ℃, 检测波长: 225 nm. 在12.5～1000 μg/L的质量浓度范围内, 格列吡嗪与内标峰的比值与质量浓度呈良好的线形关系(r=0.9959);格列吡嗪平均回收率为96.8%, 批间、批内RSD均小于6%, 检出限为12.5 μg/L (S/N≥3). 方法可用于药物代谢动力学及生物等效性的研究.     

离子迁移谱法快速筛查保健食品中非法添加降糖类药品

采用电喷雾离子迁移谱法(IMS),建立了保健食品中12种降糖类化学药物盐酸二甲双胍、盐酸苯乙双胍、甲苯磺丁脲、格列本脲、格列美脲、格列喹酮、格列吡嗪、格列齐特、盐酸罗格列酮、盐酸吡格列酮、瑞格列奈、那格列萘的快速筛查方法。考察了离子源电压、迁移管电压和迁移管温度对降糖类化学药品迁移时间和信号强度的影响,最终条件设定为:离子源电压2.5kV,迁移管电压7.0kV,进样口温度180℃,迁移管温度180℃,谱图叠加次数10,分析时间30s,采集谱图时长25ms。为保证迁移时间稳定,采用色氨酸作为校准物质进行迁移时间校正,同时进行长期稳定性考察。结果表明12种降糖药物的迁移时间在7.977~17.153ms之间,检出限在0.02~8μg·mL-1之间,在4个月内迁移时间的相对标准偏差(RSD)小于5%。16个保健食品样品用该方法进行检测,其中有6个样品检出二甲双胍,检出苯乙双胍的样品有7个,同时检出苯乙双胍和二甲双胍的样品有1个。该方法可用于建立保健食品中非法添加药品的IMS迁移时间数据库,并用于其快速筛查。     

超高效液相色谱-串联质谱法快速检测降糖类保健食品中的10种非法添加物

建立了超高效液相色谱-串联质谱快速检测降糖类保健食品中10种非法化学降糖药物(盐酸苯乙双胍、那格列奈、格列齐特、盐酸吡格列酮、盐酸罗格列酮、格列吡嗪、瑞格列奈、格列美脲、格列苯脲、格列喹酮)的方法。样品经甲醇超声提取,用Thermo Hypersil Gold色谱柱分离,采用三重四极杆质谱进行定性及定量分析。10种药物在1~1000μg/L范围内线性关系良好,检出限为0.1~1.5μg/L,在低、中、高3个添加水平范围内的平均回收率为82.5%~111.9%,相对标准偏差为2.1%~7.8%。     

高效液相色谱-质谱/质谱测定血浆中格列苯脲

本文建立了人血浆中格列苯脲的高效液相色谱-质谱/质谱(HPLC-MS/MS)分析方法。血浆中格列苯脲测定的线性范围是1~300 ng/mL;高、中、低三个浓度分析测定的精密度(RSD)<15%;格列苯脲和格列齐特(内标)绝对回收率均>80%。本方法灵敏、准确,重现性好,用于血药浓度的测定获得满意结果。     

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.