柱前衍生反相高效液相色谱法测定血清中9种胆汁酸

建立了一种柱前衍生反相高效液相色谱(RP-HPLC)测定血清中9种胆汁酸的方法。以4-溴甲基-7-甲氧基香豆素(BMC)为衍生剂,用Waters Nova C18色谱柱分离,采用甲醇／乙腈和水梯度洗脱,荧光检测,9种胆汁酸在5～40μmol／L范围内具有良好线性,r为0．9988～0．9998。回收率为85．40％～100．45％,检出限为1～2μmol／L。该法灵敏、特效、重复性好,可用于临床血清中微量胆汁酸的测定。     

固相萃取高效液相色谱-质谱法测定血浆中乙醇醛、甘油醛的含量

采用柱前衍生、固相萃取、高效液相色谱-质谱联用方法,建立了血浆中乙醇醛(GCO)、甘油醛(GCE)含量的测定方法。衍生试剂为3-m ethyl-2-benzoth iazolinone-hydrazone hydrochloride(MBTH);内标物为3-羟基丁醛;HPLC流动相为甲醇-醋酸铵(5 mmol/L),梯度洗脱;质谱电喷雾选择离子检测。比较了糖尿病大鼠和正常大鼠血浆中GCO、GCE的含量,正常大鼠血浆中GCO和GCE的含量分别为0.0574±0.0036μmol/L、0.0186±0.0019μmol/L;糖尿病大鼠血浆中GCO和GCE的含量分别为0.0763±0.0071μmol/L、0.0240±0.0023μmol/L,差异显著。     

柱前衍生高效液相色谱法分离分析1-氮杂双环[2,2,2]辛-3-基胺对映异构体

1-氮杂双环[2,2,2]辛-3-基胺是制备5-羟色胺拮抗剂药物盐酸帕洛诺司琼等的重要中间体,手性帕洛诺司琼可以通过中间体的手性分离来制备。用柱前衍生化-反相高效液相色谱法对1-氮杂双环[2,2,2]辛-3-基胺对映体进行分离并建立了检测方法。结果表明,用2,3,4,6-四-O-乙酰基-β-D-葡萄糖异硫氰酸酯(GITC)为柱前手性衍生化试剂,C18柱(300mm×4.6mm,5μm)为色谱柱,可将1-氮杂双环[2,2,2]辛-3-基胺对映体分离,其它色谱条件:流动相组成为[甲醇-乙腈-0.01mol/L四丁基溴化铵(20∶10∶75,V/V)]-(三乙胺)0·1%-(冰醋酸)0.15%,流速0.7mL/min,检测波长为266nm。在选择的测定条件下,衍生后的两非对映异构体分离度达4以上。     

冷冻鲅鱼中脂肪胺的毛细管电泳分离分析

建立了测定冷冻鲅鱼中脂肪胺的毛细管电泳检测方法.采用硼酸盐缓冲溶液为背景电解质,经10-乙基吖啶酮-2-磺酰氯(EASC)柱前衍生化后,10种脂肪胺在9 min内可实现快速高效的基线分离和测定.实验得到的优化条件为:20 mmol/L硼酸盐缓冲溶液(pH为9.2,SDS浓度为15 mmol/L),分离电压18 kV,柱...     

脂肪胺荧光衍生物的高效液相色谱分离及质谱鉴定

采用新型荧光衍生试剂2-(9-吖啶酮)-乙酸(AAA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性.衍生物荧光激发和发射波长为λex=404nm,λem=440nm.30℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应20min后获得稳定的荧光产物.在HypersilBDSC18(4.6mm×100mm,5μm)色谱柱上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离.采用大气压化学电离源(APCISource)正离子模式进行在线柱后质谱定性,实现了各种脂肪胺衍生物的快速、准确测定.该方法具有良好的重现性,多数脂肪胺的线性回归系数大于0.9996,检测限为12.09~25.52fmol.     

浊点萃取-气相色谱-质谱法测定水中9种芳香胺类化合物

本研究基于以曲拉通X-114(Triton X-114)为萃取剂的浊点萃取技术和气相色谱-质谱法,建立了一种高效、高灵敏度的水体中9种芳香胺(2-氯胺、3-氯胺、4-氯胺、2-硝基苯胺、3-硝基苯胺、4-硝基苯胺、1-萘胺、2-萘胺和4-氨基联苯)的检测方法。采用单因素优化法对影响提取效果的重要因素进行了优化。采用气相色谱-质谱对水中9种芳香胺进行定性、定量分析,使用中等极性色谱柱DB-35 MS(30 m×0.25 mm×0.25μm)进行分离,在选择离子模式(SIM)下测定,内标法定量。实验结果表明,9种芳香胺在16 min内能够完全分离,且在各自的范围内线性关系良好,相关系数(R²)均大于0.998。9种芳香胺的检出限(LOD)和定量限(LOQ)分别为0.12～0.48μg/L和0.40～1.60μg/L。选取饮用水源地地表水、近海海水和典型印染行业废水3种类型水体进行加标回收试验,在2个加标水平(2.0、10.0μg/L)下,饮用水源地地表水的加标回收率为81.1%～109.8%,日内精密度为0.7%～5.2%,日间精密度为1.6%～6.2%;近海海水的加...     

柱前衍生-高效液相色谱分离测定及质谱鉴定脂肪胺

采用新型荧光衍生试剂2-(2-苯基-1-氢-菲[9,10-d]咪唑)-乙酸(PPIA)进行柱前衍生,经荧光检测实现了脂肪胺的高效液相色谱(HPLC)分离测定及柱后质谱鉴定。60℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做缩合剂,衍生反应15min可获得稳定的荧光产物。脂肪胺衍生物荧光检测波长为380nm(激发波长为260nm)。在EclipseXDB-C8色谱柱上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离,测定了造纸厂废水、大鼠端脑和酸奶中脂肪胺的含量。经柱后在线质谱大气压化学电离源(APCISource)正离子模式实现了各种脂肪胺衍生物的质谱鉴定,借助对活性中间体的质谱解析确定了衍生反应的反应机理。该方法具有良好的重现性和回收率,多数脂肪胺的线性回归系数大于0.9996;检出限为3.1~18fmol(S/N=3∶1)。     

基于硝酮化衍生-高效液相色谱-荧光法测定环境水样中的脂肪醛

本研究以4-丁基羟胺-7-羟基-香豆素(HAHC)为荧光衍生试剂，基于硝酮化衍生生成具有良好荧光响应和色谱性能的反式产物，结合高效液相色谱-荧光检测法(HPLC-FLD),建立了水样中脂肪醛的高灵敏度、高选择性的检测方法。该方法成功分离、检测了8种脂肪醛(C2～C9),检出限低至0.2 nmol/L,且线性关系良好(R≥0.9984),重复性高，其日内相对标准偏差(RSD)≤3.97%,日间RSD≤7.69%。将其成功用于游泳池水、自来水、湖水和雨水中脂肪醛含量检测。该方法灵敏度高、结果准确且无需富集或萃取等复杂的样品预处理过程，为水体中的醛类污染物的监测提供了依据。     

柱前衍生-高效液相色谱法同时测定水产品和水发食品中4种脂肪胺

建立水产品和水发食品中甲胺、乙胺、二甲胺和二乙胺的柱前衍生-高效液相色谱同时测定方法。样品经10%三氯乙酸匀浆、离心后,取上清液与9-芴甲氧羰酰氯(FMOC-Cl)在0.10 mol/L四硼酸钠溶液中反应生成具有紫外吸收的衍生产物,然后以C18柱为分离柱、甲醇-水为流动相,流速梯度洗脱分离,以DAD检测器在265nm波长处检测,标准曲线法定量。4种脂肪胺衍生产物在16 min内可完全分离。在0.5～25μg/mL浓度范围内,各物质的质量浓度与色谱峰面积均具有良好线性关系(r>0.999),方法检出限分别为:甲胺0.05 mg/kg、乙胺0.21 mg/kg、二甲胺0.29 mg/kg、二乙胺0.80 mg/kg。方法的加标回收率为88.1%～100.7%,相对标准差均小于5%。方法可用于水产品和水发食品中4种脂肪胺的同时快速测定。     

液相色谱法测定婴幼儿食品包装材料中的脂肪胺

采用新型气流吹扫-微注射器萃取( GP-MSE)技术,用酸化甲醇为提取溶剂,对食品包装材料中脂肪胺进行了提取和富集。以10-乙基-吖啶酮-2-磺酰氯( EASC)为荧光试剂,在60℃、pH 10的条件下,对脂肪胺进行柱前荧光衍生, Hypersil GOLD柱分离,荧光检测的激发波长(λex )和发射波长(λem )分别为262 nm和430 nm。12种脂肪胺检出限为0.4~0.6μg/kg,定量限为1.2~2.1μg/kg,在2.0~2000μg/L浓度范围内,线性相关系数均大于0.998。本方法具有快速、准确、灵敏的特点,用于婴幼儿食品包装材料分析,结果令人满意。     

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%.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.