高效液相色谱-串联质谱法检测红葡萄酒中功效成分

建立了高效液相色谱-串联质谱法快速测定葡萄酒中白藜芦醇、黄酮类、多酚类功效成分的分析方法。葡萄酒样品直接稀释后进样,用C18柱进行分离,以乙腈-0.1%(体积分数)甲酸水溶液为流动相进行梯度洗脱,通过多反应监测(MRM)模式进行检测。13种功效成分在各自线性范围内呈良好的线性关系,相关系数均大于0.99。除表没食子儿茶素、没食子儿茶素、儿茶素没食子酸酯、花旗松素的检出限为1.0、1.0、3.0、3.0μg/L外,其他9种化合物的检出限均小于1.0μg/L。回收率为80.9%~112.3%,相对标准偏差小于10%。该方法快速、准确、灵敏度高,适用于葡萄酒中功效成分的快速分析。对实际样品的检测表明,所测葡萄酒样品中均含有儿茶素、表儿茶素、表没食子儿茶素、没食子儿茶素、表儿茶素没食子酸酯/儿茶素没食子酸酯、白藜芦醇、大豆黄素等功效成分,不同品种葡萄酒中这些功效成分含量差异显著。     

HPLC法测定茶叶中儿茶素及咖啡碱

以绿茶为样本,以GB/T 8305–1987水浸出方式作为样品的提取方法,使用C18色谱柱(150 mm×4.6mm,5μm),以A相(超纯水)、B相(N–N二甲基甲酰胺︰甲醇︰冰乙酸=40︰2︰1.5)为流动相,在最佳梯度洗脱条件下对8种组分进行分离,紫外检测器检测,检测波长为278 nm,外标法定量。没食子酸、咖啡碱、表没食子儿茶素、儿茶素、表儿茶素、表没食子儿茶素没食子酸酯、没食子基儿茶素没食子酸酯和表儿茶素没食子酸酯8种组分的进样质量分别在0.0243~0.1456,0.2549~1.5296,0.2027~1.2164,0.0182~0.1102,0.1606~0.9634,1.0004~6.0024,0.018 2~0.109 0,0.229 6~1.377 4μg范围内与色谱峰面积的线性关系良好(r为0.991 0~0.999 9);加标回收率为98.60%~100.17%,RSD均小于0.48%(n=3)。对样品进行6次重复测定,与标准方法相比,8种组分测定结果的相对偏差为0.47%~5.55%。该方法简便、快速、准确、稳定、重复性好,可用于茶叶中8种成分的定量分析。     

高效液相色谱法分析元宝枫叶中儿茶素类物质

本文建立了元宝枫树叶中儿茶素种类及其含量的高效液相色谱(HPLC)测定方法。采用反相C18色谱柱,以甲醇/水(含0.5%乙酸)=25/75(V/V)为流动相,对没食子儿茶素(GC)、表没食子儿茶素(EGC)、儿茶素(C)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素(EC)和没食子儿茶素没食子酸酯(GCG)进行定性、定量分析;以甲醇/水(含0.5%乙酸)=35/65(V/V)为流动相,对表儿茶素没食子酸酯(ECG)和儿茶素没食子酸酯(CG)进行定性分析,柱温均为35℃,检测波长为278 nm,流速为1.0mL/min。结果表明:元宝枫叶中有EGC、EC和GCG,其它五种则无。EGC平均含量为0.0389 mg/g,方法精密度(RSD)为0.42%(n=6);EC平均含量为0.0289 mg/g,方法RSD为1.5%(n=6);GCG平均含量为0.284 mg/g,方法RSD为0.32%(n=6)。该方法简便、准确、分离效果好,为元宝枫叶开发成茶叶、饮料以及医疗保健品提供重要依据。     

高效液相色谱法测定绿茶中茶多酚及咖啡因

应用高效液相色谱法测定绿茶中没食子酸(GA)、咖啡因(CAF)及5种儿茶素类化合物,包括儿茶素(C)、表儿茶素(EC)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素没食子酸酯(ECG)、没食子儿茶素没食子酸酯(GCG)。对国家标准方法GB/T 8313-2008中流动相组成进行了调整,用0.5%乙酸代替2%的乙酸,在AT.Lichrom ODS色谱柱(4.6mm×250mm,5μm)上进行分离,流量为1.0mL.min-1,在波长278nm处进行紫外检测。7种组分在40min内达到完全分离。7种组分的质量浓度分别在一定的范围内与其峰面积呈线性关系。方法用于绿茶的分析,7种组分的加标回收率在96.0%～102.8%之间。     

茶中儿茶素的分离分析方法研究进展

儿茶素类是茶叶药效的主要活性组分.天然产生的八大儿茶素为儿茶素(C)、表儿荼素(EC)、没食子儿茶素(GC)、表没食子儿荼素(EGC)、儿茶素没食子酸酯(CG)、表儿荼素没食子酸酯(ECG)、没食子儿荼素没食子酸酯(GCG)、表没食子儿茶素没食子酸酯(EGCG).本文综述了分离分析茶儿荼素的常用有效方法.     

半制备型液相色谱法分离纯化茶叶鲜叶中7种儿茶素类化合物

建立了从茶叶鲜叶中分离纯化7种儿茶素类化合物(没食子儿茶素(GC)、表没食子儿茶素(EGC)、儿茶素(C)、表没食子儿茶素没食子酸酯(EGCG)、表儿茶素(EC)、表没食子儿茶素3-O-(3-O-甲基)没食子酸酯(EGCG3"Me)和表儿茶素没食子酸酯(ECG))的半制备色谱法。铁观音鲜叶经甲醇超声浸提、浓缩、氯仿萃取后,向水相中加入碱式醋酸铅沉淀,得到茶多酚粗品。分别以甲醇-水、乙腈-水作为流动相,采用半制备色谱法纯化7种儿茶素类化合物,纯度均达到90%。此外,利用同样的方法分离纯化另外两种茶叶鲜叶中的7种儿茶素类化合物,得到相似的结果。该方法以溶剂提取、离子沉淀结合半制备色谱,适于简单、高效地同时分离制备多种儿茶素类化合物。     

高效液相色谱/质谱分析茶树老叶中儿茶素

1　引　　言儿茶素是一类能改进血管渗透性能 ,增强心肌 ,降低血压 ,并具有抗脂肪肝、抗癌和Ｖｐ样作用的天然活性物质 ,采用高效液相色谱 质谱 (ＬＣ ＭＳ)联用法分析儿茶素至今未见报道。本文采用ＬＣ ＭＳ联用法 ,优化了色谱条件 ,同时分离了茶树老叶中 7种儿茶素 ,并以ＨＰＬＣ与ＬＣ ＥＳＩ ＭＳ联合定性 ,鉴定出 7种儿茶素分别为表没食子儿茶素 (ＥＧＣ)、没食子儿茶素 (ＧＣ)、表没食子儿茶素 3 没食子酸酯 (ＥＧＣＧ)、表儿茶素 (ＥＣ)、没食子儿茶素 3 没食子酸酯 (ＧＣＧ)、表儿茶素 3 没食子酸酯 (ＥＣＧ)、儿茶素 3 没食子…     

高效液相色谱法测定茶叶中茶多酚

应用高效液相色谱法测定了茶叶,特别是绿茶中的8种多酚,包括儿荼素(C)、表没食子儿茶素(EGC)、没食子儿荼素(GC)、表儿茶素(EC)、表没食子儿茶素没食子酸酯(EGCG)、没食子儿荼素没食子酸酯(GCG)、表儿茶素没食子酸酯(ECG)及儿茶素没食子酸酯(CG).在C18>反相柱(250 min×4.6 mm,5 μm)上进行分离,用不同体积比混合的流动相A及流动相B的混合液作梯度淋洗,流速为1.0 mL·min-1,柱温为40℃,在280 nm波长处进行紫外检测.上述8组分在0.004～4.0 g·L-范围内呈线性关系,方法的检出限在0.6～2.6 mg·L-1范围内,平均回收率为83%.     

反相高效液相色谱法同时测定茶叶中六种儿茶素组分的研究

采用反相高效液相色谱法同时测定茶叶中L (+) 表儿茶素(L EC),L (-) 表儿茶素没食子酸酯(L ECG),L (-) 表没食子儿茶素没食子酸酯(L EGCG),L (-) 表没食子儿茶素(L EGC),(+) 没食子儿茶素没食子酸酯(GCG),DL 儿茶素(DL C)六种儿茶素组分,以乙醇∶乙酸∶水=14.5∶1.0∶84.5(体积比)为流动相(1.0ml·min-1),C18柱,UV检测器(278nm)。六种儿茶素组分的相对标准偏差分别为0.67%,0.45%,0.24%,0.56%,3.11%,4 41%,回收率分别为95.2%,98.2%,101.3%,97.0%,98.3%,97.5%。该法采用乙醇、乙酸等无毒溶剂作流动相,回收率高,用于实际样品测定,结果满意。     

毛细管区带电泳法测定葡萄籽中儿茶素类化合物

 采用毛细管区带电泳法测定了 10种中国产葡萄籽中的 4个主要儿茶素类化合物 :(+)儿茶素、(- )表儿茶素、(± )表没食子儿茶素、(± )表儿茶素没食子酸酯的含量。在 0 0 2mol/L硼砂和 0 0 0 5mol/L磷酸盐的混合缓冲体系 (pH 10 0 )的背景缓冲液中 ,4个化合物在 10min内取得了令人满意的分离。迁移时间的重现性(RSD)小于 2 % ,峰面积的重现性 (RSD)小于 5 %。在质量浓度为 0 0 0 5g/L～ 0 5 g/L时 ,线性相关系数大于0 995。检测限为 3mg/L～ 10mg/L。该方法简单、快速、准确 ,可作为葡萄籽分析和药用开发过程中分析儿茶素类化合物的有效方法推广使用。     

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.     

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.     

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.     

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.