微波提取-GC/MS-SCAN/SIM法定量检测野菊花挥发油中1,8-桉叶素,樟脑,异龙脑,龙脑

建立了一种微波辅助提取(MAE)野菊花挥发油及气相色谱-质谱(GC-MS)同时定性和定量测定挥发油中1,8桉-叶素、樟脑、异龙脑和龙脑的方法。方法相对标准偏差小于2.65%,回收率为94.16%~103.73%,检出限为0.025mg/L。用SCAN/SIM方法,测定结果受干扰小,准确可靠,方法灵敏度高,重现性好。比较了水蒸气蒸馏和微波提取挥发油的效果,结果显示微波提取的效率更高。应用此方法分析不同产地野菊花中上述成分的含量,发现含量相差较大。     

气相色谱法测定冠心膏中樟脑、薄荷脑、异龙脑、龙脑的含量

用气相色谱法测定了冠心膏中樟脑、薄荷脑、异龙脑和龙脑的含量。固定相：７％ＰＥＧ－１５００,线性范围：５～４５０ｍｇ／Ｌ（ｒ＝０．９９９４～０．９９９９）。回收率：樟脑为９８．４４％,薄荷脑为９９．０１％,异龙脑为９９．６９％,龙脑为１０１．９％。     

微柱高效液相色谱法分离八角茴香挥发油成分

利用微柱高效液相色谱法(μ-HPLC)对八角茴香果实挥发油成分进行了分离,对固定相类型、流动相组成及流速等条件进行了优化。结果表明,选用氰基分析柱(250mm×0.32mmi.d.,5μm),正己烷-乙腈-二氯甲烷(80∶8∶12,体积比)为流动相,流速为2μL·min-1,八角茴香果实挥发油成分在微柱液相色谱上分离效果最好。在优化的实验条件下,对实际样品中反式-茴香醚、茴香醛等成分进行了定量。本实验为以后的μ-HPLC与毛细管气相色谱联用分析植物挥发油奠定了基础。     

气相色谱分析过程的计算机仿真模拟与优化

以色谱法的ＬＥＳ模型作为气相色谱分析过程的计算机仿真模拟与优化的理论基础，提出了把两次多阶程度升温实验保留时间作为基本数据进行模拟优化的方法，拓宽了模拟优化方法在复杂组分样品中的应用。软件编程采用了计算数学方法，提高了模拟优化的精度和速度，节省了分析样品的时间。     

广东野菊花挥发油的化学成分

采用水蒸汽蒸馏法从野菊花中提取挥发油,试用不同类型的毛细管柱进行分析,找出了最佳分析条件,共分离出54个峰,用归一化法测定其相对含量,并用气相色谱-质谱法对化学成分进行鉴定,共鉴定18个成分,占挥发油总量的99.8%。     

仪器分析综合实验:固相微萃取纤维的制备及在有机氯农药富集和分析中的应用*

设计了一个综合性仪器分析实验:固相微萃取纤维的制备及应用。实验内容包括微孔有机聚合物固相微萃取纤维的制备、红外光谱表征、固相微萃取实验条件优化和气相色谱测定有机氯农药含量等4个部分。通过综合运用多种仪器分析实验手段,加深了学生对分离富集技术的了解,巩固了学生对仪器分析课程中的气相色谱法、红外光谱法相关内容的掌握,培养学生构建一个完整、科学的仪器分析操作流程,形成综合性思维能力。     

气相色谱法测定牙痛水中樟脑和丁香酚的含量

牙痛水临床用于龋齿所致的疼痛。内含樟脑和丁香油等,樟脑定量采用经典的重量法,分析周期长达30多小时,操作烦琐费时,结果误差大。丁香油中的丁香酚无含量测定方法。为此,作者建立了定量分析牙痛水中樟脑和丁香酚含量的气相色谱法,方法简单快速,结果准确。     

野菊花挥发油化学成分的气相色谱-质谱联用分析

野菊花(Flos chrysanthemum indici)为菊科植物野菊((7hrysanthemum indicum L．)的头状花序,临床应用广泛。它主要含挥发油、黄酮、倍半萜及其他成分,其中挥发油对肺炎双球菌、流感杆菌、金黄色葡萄球菌等均有较强的抑制作用。关于野菊花挥发油的化学成分已有报道。由于生长环境的差异,不同产地的野菊花药效差异较大,挥发油中各组分含量也有较大差异。我们采集江西产野菊花药材,采用气相色谱-质谱联用(GC—MS)技术,     

卷烟主流烟气气相物和总粒相物中有机酸的分析研究

以二氯甲烷-甲醇为萃取溶剂,N,O-双(三甲基硅基)三氟乙酰胺(BSTFA)为硅烷化试剂,采用配备氢火焰离子化检测器(FID)的气相色谱仪分别对卷烟主流烟气中气相物和总粒相物中甲酸、乙酸、硬脂酸等21种有机酸进行了定量分析。对样品主流烟气中气相物前处理硅烷化条件及有机酸萃取条件进行了优化,并采用气相色谱法对卷烟主流烟气中气相物和总粒相物中有机酸的含量进行了定量分析。该方法用于实际样品中挥发性有机酸分析时,回收率为88.12%～98.63%,相对标准偏差(RSD)为1.51%～8.38%。     

生物样本中的甲基苯丙胺和氯胺酮含量的检测研究及其体内分布初探

建立了生物样本中甲基苯丙胺和氯胺酮的定量检验方法,该方法应用固相萃取与工作曲线气相色谱法(GC/NPD)对中毒者血、尿、胃内容、肝、脑等检材进行含量测定.通过实际案件,验证了该法具有样品处理简单、提取效率高、分析速度快等优点.案件数据表明,由口服引起的中毒途径,胃内容的含量最高,其次是尿、肝、脑、血等检材,进一步证实了...     

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%.     

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.     

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.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.