分子印迹液相色谱整体柱

分子印迹是合成预定选择性固定相的新兴技术,整体柱是新型的色谱固定相技术。将分子印迹聚合物与整体柱技术相结合,可以有效提高液相色谱的分离效率,有助于推动整个分离科学的发展,意义重大,是当今分析化学的研究热点。本文就分子印迹液相色谱整体柱的制备合成、色谱分离条件以及物理化学特性评价方法等方面的研究进展进行了较系统的综述,并对该技术目前存在的问题和发展前景进行了探讨。     

分子印迹整体柱在样品前处理及色谱分析中的应用

分子印迹整体柱(MIPMC)结合了分子印迹聚合物的立体选择性高和整体柱制备简单、柱压低以及传质速率快等优点,是一种极具应用潜力的样品前处理介质和色谱固定相.该文详细介绍了分子印迹整体柱的制备方法,综述了近年分子印迹整体柱在样品前处理及色谱分析中的应用进展,并对其发展趋势做了展望.     

分子印迹整体柱富集-高效液相色谱法测定植物中的痕量细胞分裂素

采用分子印迹整体柱富集-高效液相色谱法选择性分离分析了植物样品中痕量细胞分裂素的含量。结果表明,以激动素为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,甲苯与十二醇为致孔剂,可在不锈钢柱管中原位聚合制备激动素分子印迹整体柱;与非分子印迹整体柱对比,该分子印迹整体柱能选择性富集4种细胞分裂素,具有较好的重复性和高的萃取效率;在优化的实验条件下,激动素(K)、激动素核苷(KR)、反式-玉米素(tZ)和meta-topolin(mT)的平均加标回收率分别为91.9%、80.0%、87.5%和50.2%,相对标准偏差均小于11.8%。本方法已成功地用于不同植物样品中4种细胞分裂素的分离和分析。     

对羟基苯甲酸分子印迹毛细管电色谱整体柱的制备与评价

<正>分子印迹(MIP)是合成预定选择性固定相的新兴技术[1-3],毛细管电色谱(CEC)是一种新型高效微分离技术[4-5],CEC和MIP相结合是当前的前沿课题之一。以对羟基苯甲酸为模板分子,采用在线热聚合制备毛细管电色谱整体柱的研究取得了满意的效果[6-7];以布洛芬为模板分子,以2-乙烯基吡啶为功能单体制备分子印迹毛细管电色谱整体柱,成功用于分离布洛芬同分异构体[8],以(S)-腺苷蛋氨酸为模板分子,采用热引发一步法制备分子印迹毛细     

咖啡因分子印迹固相萃取柱的制备及应用

以咖啡因作为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,制备了咖啡因分子印迹聚合物(MIP)。与非印迹聚合物(NIP)相比,MIP对咖啡因具有更高的吸附容量和选择性,MIP和NIP对咖啡因的最大静态吸附量分别为28.1和16.5mg/g,相对选择因子为1.25。以咖啡因分子印迹聚合物为固相萃取填料,结合高效液相色谱(HPLC),建立了茶水中咖啡因浓度及人饮茶后血清中咖啡因浓度的检测方法。考察了洗脱剂种类和用量对咖啡因回收率的影响。当萃取柱依次以2mL水活化,水溶液上样,2mL水淋洗,6mL甲醇-乙酸(9∶1,V/V)洗脱,咖啡因在MIP固相萃取柱上的回收率达到97.5%,而在NIP柱上的回收率仅为54.9%。     

咖啡因印迹复合膜的制备及性能研究

以孔径0.45 μm的尼龙微孔滤膜为支撑膜, 咖啡因为模板分子, 丙烯酰胺为功能单体, 乙二醇二甲基丙烯酸酯为交联剂, 采用表面热聚合技术制备对咖啡因具有优良选择透过性的分子印迹复合膜. 采用高效液相色谱技术探讨了不同功能单体印迹聚合膜选择渗透性能的影响, 采用红外光谱分析、X射线衍射分析、热重分析和液相色谱分析等技术对分子印迹膜的化学结构、晶体结构、孔隙率、溶胀性、热稳定性以及选择性等性能进行详细的研究. 结果表明以丙烯酰胺为功能单体的印迹复合膜对咖啡因具有优异的选择透过性, 其分离选择性因子为2.3. 该印迹膜呈现出较好的结合能力, 对印迹分子存在两个结合位点, 最大表观结合量分别为0.146和0.330 μmol/g, 能够较好地应用于山茶叶粗提液中咖啡因的分离和富集, 富集因子为10.52.     

分子印迹磁固相萃取法测定饮料中咖啡因含量

建立了一种磁性分子印迹固相萃取和气相色谱相结合测定饮料中咖啡因含量的新方法。该法自制磁性分子印迹固相萃取材料作为萃取剂,将其分散在样品溶液中,利用外部磁场使磁性萃取剂与溶液快速分离,结合分子印迹技术,提高对分析物的选择性吸附,排除了样品中各类干扰杂质。在最佳条件下进行分析,该方法的检出限为0.05μg/m L(S/N=3),线性范围为0.1~15μg/m L,线性相关系数(R~2)为0.999 1,本法可用于可口可乐、百事可乐、红牛和黑卡六小时试样中咖啡因含量的测定。     

咖啡酸分子印迹聚合物的制备及其用于咖啡酸的高效液相色谱分离

以咖啡酸为模板分子,丙烯酰胺为功能单体,在水溶液中合成了咖啡酸分子印迹聚合物,制备了分子印迹聚合物色谱分离柱。试验结果表明:聚合物对印迹分子具有很好的亲和性和特异选择性,以甲醇-水(25+75)混合溶液为流动相,咖啡酸与其相似物绿原酸的分离度达到1.91。     

桃叶珊瑚苷-硼酸共聚印迹整体柱的制备及其分子识别性能

以桃叶珊瑚苷为模板,4-乙烯基苯基硼酸为功能单体,制备了桃叶珊瑚苷-硼酸共聚印迹整体柱。考察了分子印迹整体柱的通透性、选择保留性能、吸附及固相萃取性能。结果表明,整体柱通透性好,当使用体积比为49∶1的甲醇-1%HCl混合溶液为流动相时,其对模板具有最强的保留能力和较高的选择性,容量因子高达166.4,选择因子最高达3.200。前沿分析表明整体柱的饱和吸附量达95.16 mg·g^-1。Scatchard分析显示印迹材料主要有两类吸附位点。当分子印迹柱用于从杜仲籽粨粗提物中分离纯化桃叶珊瑚苷时,可获得含量高于85%的产品。当整体柱用于分离分析时,方法的检出限和定量限分别为0.167 mg·kg^-1和0.547 mg·kg^-1,且整体柱可重复使用。     

2,4-二氯苯氧乙酸分子印迹整体柱的制备、表征及色谱性能研究

以2,4-二氯苯氧乙酸分子为模板,甲基丙烯酸为单体,乙二醇二甲基丙烯酸酯为交联剂,甲苯和十二醇为混合致孔剂,采用热引发原位聚合法制备了作为高效液相色谱固定相的分子印迹整体柱.用红外光谱、扫描电镜、比表面积分析法对聚合物进行了表征.考察了模板分子在不同条件下合成的印迹整体柱及空白整体柱上容量因子的变化规律,同时探讨了流动相中甲醇的体积分数、pH值、流速对印迹整体柱分离性能的影响.结果表明,在优化的合成条件下制备的分子印迹整体柱可在15 min内分离2,4-二氯苯氧乙酸及其类似物苯氧乙酸,分离度为1.52.对柑桔提取液进行了分离测试,结果满意.     

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%.     

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.     

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.     

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.     

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.     

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.     

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.