甘脲和羟基葫芦[6]脲气相色谱固定相的制备及其色谱分离性能比较研究

甘脲是羟基葫芦[6]脲(HOCB6)的前体, 本文设计了一种在酸性条件下均匀涂渍固定液的新方法, 首次将甘脲和羟基葫芦[6]脲用作气相色谱固定相. 将甘脲和HOCB6填装成气相色谱填充柱后, 以烷烃、卤代烃、芳香烃、醇、酮、酯、酸、胺等物质为探针, 用复杂样品花露水对它们的色谱分离性能进行了比较研究. 结果表明, 甘脲和HOCB6 都是良好的气相色谱固定相, 热稳定性高, 柱性能稳定. 两种固定相对以上溶质探针都有较好的分离能力, HOCB6固定相(PSP)与甘脲固定相(GSP)相比较, 总体上具有更好的分离选择性, 对难分离的芳香族位置异构体(如二甲苯、甲基苯胺)具有良好的分离能力, 显示出较高的立体选择性, 对花露水中的高沸点组分有较好的分离效果. 上述研究也表明, 由于溶质在载气中传质比葫芦脲内腔快得多, 全包结尽管有利于提高分离选择性, 但展宽后的柱效不理想; 适当的高柱温既保留了部分包结作用, 同时存在端口协同作用, 能兼顾高选择性和高柱效.     

硅藻土载负葫芦[7]脲气相色谱固定相的制备及其性能评价

在酸性条件下,将自制的葫芦[7]脲均匀地涂覆到102白色硅藻土担体上,制得葫芦[7]脲气相色谱固定相。 采用红外光谱、质谱、元素分析和热重分析表征了葫芦[7]脲在载体表面的结构。 利用相关探针测定了新固定相的麦氏常数,表征了其基本色谱性能。 考察了葫芦[7]脲气相色谱固定相填充柱对芳香烃、卤代烃、醇、酮、酯及硅氧烷的分离能力。 结果表明,葫芦[7]脲固定相热稳定性高,柱色谱性能稳定,对较广泛的化合物尤其对高沸点的酯类及硅氧烷类化合物显示出良好的色谱分离能力(7 min内分离),作为气相色谱固定相有较好的应用前景。 初步讨论了葫芦[7]脲固定相对上述化合物的分离机理。     

光谱法研究羟基葫芦[6]脲与对氨基苯磺酸的分子识别作用

光谱法研究羟基葫芦[6]脲与对氨基苯磺酸的分子识别作用;紫外光谱法;荧光光谱法;分子识别;包结作用;羟基葫芦[6]脲;对氨基苯磺酸     

嘌呤衍生物在葫芦［6］脲单轮烷键合固定相上的色谱行为

在反相和正相色谱模式下,研究了几种嘌呤衍生物在葫芦［6］脲单轮烷键合硅胶固定相上的高效液相色谱行为,并在反相模式下与ODS固定相进行了比较,考察了流动相中甲醇含量、流动相pH值和离子强度对嘌呤化合物保留的影响。研究结果表明:在反相模式下,嘌呤化合物与葫芦［6］脲单轮烷键合相之间存在多种相互作用,除疏水作用外,分离过程中还存在与ODS不同的色谱分离机制。在正相条件下,多作用力的色谱分离机制同样存在。葫芦［6］脲单轮烷键合相与溶质之间存在疏水、氢键、π-π和偶极-偶极等多种作用力,协同作用提高了固定相对嘌呤化合物的分离选择性。     

葫芦[6]脲单轮烷键合固定相的制备、表征及色谱性能

将超分子自组装技术与色谱键合硅胶固定相制备技术相结合,采用γ-[(2,3)-环氧丙氧]丙基三甲氧基硅烷(KH-560)为偶联剂,首次将一种葫芦[6]脲单轮烷(CB6MR)键合到硅胶上,制备了一种新型的葫芦[6]脲单轮烷键合固定相(CB6MRBS)。通过元素分析、红外光谱和热分析对该固定相进行了结构表征。以中性、酸性、碱性化合物和二取代苯位置异构体等溶质为探测因子,分别在反相和正相色谱模式下对固定相的色谱性能和保留机理进行了研究。结果表明：CB6MRBS是一种多模式键合固定相,具有良好的正相和反相色谱性能,对位置异构体具有较高的识别能力,尤其是可有效地用于碱性化合物的分离分析。其保留机理存在氢键、静电、π-π和疏水作用等多种作用力机制,协同作用提高了CB6MRBS对溶质的分离选择性。由于CB6MR配体中含有酰胺基和众多极性羰基,CB6MRBS可能在络合色谱面有应用前景。     

甘脲用作气相色谱固定相的色谱性能研究

甘脲具有双环双脲结构,既是质子给体,又是质子受体,能与溶质产生氢键作用等多种作用力。本文制备了以甘脲作为固定相的填充柱,并对它的色谱性能进行了研究。结果表明:甘脲固定相热稳定性高、柱性能稳定,是一种良好的气相色谱固定相。该固定相对烷烃、卤代烃、芳烃、醇、酯、酮、酸、胺等类物质具有良好的分离能力,尤其是对位置异构体(如二取代苯位置异构体)有较好的分离选择性。本文还初步探讨了甘脲固定相的分离机理。     

新型靛红衍生化β-环糊精键合SBA-15液相色谱固定相的制备与表征

利用靛红的羰基与β-环糊精单取代乙二胺的缩合反应,合成得到种靛红衍生化β-环糊精Schiff碱类化合物。以3-异氰酸丙基三乙氧基硅烷为偶联剂,将其键合到自制的有序介孔二氧化硅材料SBA-15表面,制得种新型的靛红衍生化β-环糊精键合SBA-15液相色谱固定相(ISCDP)。分别对β-环糊精衍生物、SBA-15及固定相进行必要的结构表征。在反相色谱条件下,以卤代尿嘧啶类极性化合物和二取代苯位置异构体为探针,评价新固定相的基本色谱性能。在极性有机溶剂和反相模式下,将新固定相分别用于β-受体阻滞剂药物和丹磺酰化氨基酸对映体的拆分,探讨了相关色谱分离机理。实验表明,靛红吲哚环的引入,增强了环糊精类固定相对卤代尿嘧啶的反相色谱分离能力,分析时间小于7 min。固定相分离硝基苯胺、氨基苯酚和苯二酚的位置异构体时也表现出较高的立体选择性,其中对位异构体均后被洗脱,这与包结作用相关;靛红衍生化β-环糊精配体也提高了固定相的手性分离能力,除疏水作用外,靛红衍生化β-环糊精配体还能提供偶极、氢键、π-π和包结等作用,多种协同作用力有利于提高新固定相的手性和非手性分离的选择性。SBA-15作为键合基质,其有序的孔结构有利于保持色谱柱的良好渗透性和小的传质阻力,在快速高效分离分析中具有应用潜能。     

葫芦[7]脲的合成及其与甲基橙的超分子行为研究——综合性研究型实验设计

以尿素为原料合成甘脲,再与甲醛反应合成葫芦脲,然后通过红外、紫外、核磁对其进行表征。详细研究了葫芦[7]脲与甲基橙的超分子包结行为。本实验可使学生接触到超分子化学,有利于学生了解有关葫芦脲的合成方法和包结性质,提高综合分析问题和解决问题的能力。     

二苯并-18-冠-6与杯环芳烃毛细管气相色谱混合固定相的协同效应研究

在气相色谱混合固定相中 ,一直认为具有加和效应 .但近年来我们 [1,2 ] 在研究特殊选择性气相色谱混合固定相时 ,在填充柱气相色谱中发现了协同效应 ,并在气相色谱领域运用协同效应概念( Synergistic Effect) ,而后又在毛细管气相色谱中观察到这种现象 [3,4 ] .由于冠醚有一个洞穴的结构 ,并存在氢键作用 ,因此对很多极性的位置异构体的分离具有高选择性 [5] .杯芳烃也是一个具有洞穴式结构的特殊分子 ,它能与一些金属离子和有机分子形成包合物 ,已被用于分离位置异构体 [6 ] .本文将二苯并 - 1 8-冠 - 6与杯环芳烃的衍生物组成混合固定相 …     

葫芦脲用作固相微萃取涂层新材料

本文对葫芦脲(CB)作为一种新型固相微萃取(SPME)涂层材料进行了研究并用于中药白豆蔻的气相色谱分析测定.本文采用的CB SPME涂层制备方法简便、快速,并具有良好的热稳定性和重复性.CB[6]SPME萃取得到的主要成分与水蒸气蒸馏（SD）法基本一致,并且CB[6]SPME对色谱后流出的目标成分的相对峰面积比明显高于SD法和商品SPME萃取材料PDMS/CAR和PDMS/DVB,这可能是由于葫芦脲的特殊分子结构及其与组分分子间选择性作用所致.葫芦脲作为一种新型SPME涂层材料具有很大的研究潜力和应用前景.     

Perhydroxylcucurbit[6]uril as a highly selective gas chromatographic stationary phase for analytes of wide‐ranging polarity

This work describes the separation performance of a perhydroxylcucurbit[6]uril stationary phase for capillary gas chromatography. The perhydroxylcucurbit[6]uril stationary phase exhibits higher resolving capabilities for critical analytes with better peak shapes than cucurbit[6]uril and conventional stationary phases. The advantageous separation feature of the perhydroxylcucurbit[6]uril stationary phase may originate from its unique structure and favorably balanced interactions with the analytes. Also, the perhydroxylcucurbit[6]uril column shows good separation repeatability with relative standard deviations in the range of 0.01–0.13% for intraday, 0.37–0.82% for interday, and 1.0–4.7% for column‐to‐column repeatability.     

Host–guest interactions of thiabendazole with normal and modified cucurbituril: 1H NMR,phase solubility and antifungal activity studies

Guest–host inclusion complexes between thiabendazole (TBZ) and cucurbit[7]uril (Q[7]), symmetrical tetra-methylcucurbit[6]uril (TMeQ[6]) and meta-hexamethyl-substituted cucurbit[6]uril (HMeQ[6]) in aqueous solution were investigated by ¹H NMR spectroscopy and phase solubility studies. The antifungal activities of the inclusion complexes were also determined. Analysis of the ¹H NMR spectra revealed that the host Q[7] selectively binds the benzimidazole ring moiety of the guest molecule and that the thiazole ring is encapsulated into the cavities of TMeQ[6] and HMeQ[6]. Phase solubility diagrams were analysed using rigorous procedures to obtain estimates of the complex formation constants for Q[n]-TBZ complexation. The phase solubility studies showed that TBZ solubility increased as a function of Q[7], TMeQ[6] and HMeQ[6] concentrations. We found that complexation of TBZ with Q[n] increased the inhibitory effect of TBZ on the growth of Fusarium graminearum. Our results thus demonstrate that complexation of TBZ with Q[n] could be used to improve the solubility and antifungal activity of TBZ.     

Chromatographic behavior of a new hybrid type RP material containing silica bonded 1,3‐alternate 25,27‐bis‐[cyanopropyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene

A novel 1,3‐alternate 25,27‐bis‐[cyanopropyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene‐bonded silica gel stationary phase (CalixPrCN) was prepared and its structure was confirmed by ATR‐FTIR spectroscopy and elemental analysis. The CalixPrCN phase was characterized in terms of its surface coverage, hydrophobic selectivity, aromatic selectivity, shape selectivity, hydrogen bonding capacity, residue metal content, and silanol activity based on Tanaka, Lindner, and SMR 870 test protocols. The effect of the acetonitrile content on the retention and selectivity of the selected neutral, basic, and acidic solutes was studied. The neutral and acidic analytes exhibited classical RP behavior, in which retention time decreases with increasing acetonitrile content. In contrast, basic analytes showed an increase in retention at low and high percentages of acetonitrile, forming “U‐shaped” retention profiles. The new calixarene phase was compared with previously reported 1,3‐alternate 25,27‐bis‐[propyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene stationary phase and commercial cyanopropyl column. The results indicate that the CalixPrCN stationary phase behaves like RP packing; however, inclusion complex formation, dipole–dipole, and π–π interactions seem to be involved in the separation process. The selectivity of this phase was demonstrated in separation of polynuclear aromatic hydrocarbons, non‐steroidal anti‐inflammatory drugs, and sulfonamides as analytes.     

Characterization of a Cellulose Trisphenylcarbamate/1-Octyl-3-methylimidazolium Tetrafluoroborate Mixture as GC Stationary Phase: Thermodynamic Parameters and LSER Methodology

A novel cellulose trisphenylcarbamate/1-octyl-3-methylimidazolium tetrafluoroborate [CTPC/[OcMIM]BF₄] gas chromatographic stationary phase was prepared and characterized utilizing thermodynamic parameters and LSER methodology. The results revealed that the interaction model of each probe molecule on the CTPC/[OcMIM]BF₄ stationary phase was invariable within the temperature range studied because of an excellent linear relationship between lnk and 1/T for each probe molecule. The chromatographic retentions of all probe molecules on the CTPC/[OcMIM]BF₄ stationary phase were enthalpy-driven processes. The main interaction forces of the stationary phase with probe molecules are hydrogen bonding interactions, dispersive interactions and dipole–dipole interactions. Moreover, the contribution of each interaction is in the order of hydrogen bonding interaction > dispersive interaction > dipole–dipole interaction. The mixture of CTPC and [OcMIM]BF₄ used as capillary gas chromatography stationary phase had high column efficiency and good film-forming ability, which was suitable for the separation of both nonpolar and polar compounds. Particularly the separation efficiencies of aromatic amines on CTPC/[OcMIM]BF₄ are superior to those on the commercial SE-54 column.

     

Ionic liquid‐bonded polysiloxane as stationary phase for capillary gas chromatography

Ionic liquid (IL) stationary phase is especially suitable for separation of complex samples, owing to the “dual nature” of IL. In this study, a synthetic method of ionic liquid‐bonded polysiloxane (PSOIL) as stationary phase of GC was proposed. Then, the PSOIL was used to prepare an 8 m capillary column by static method. The column efficiency was measured to be about 4000 plates/m (k=3.55, naphthalene) after the column had been conditioned at 210°C. The durability of PSOIL column was better than that of the mixed stationary phase of IL and OV‐1. Moreover, the Abraham solvation parameter model was employed to characterize the PSOIL. The result revealed that the PSOIL had stronger dispersion force (l) than neat IL and stronger hydrogen bond basicity (a) than DB‐1. That meant the PSOIL might offer good selectivity for both polar and non‐polar analytes. The column exhibited unique selectivity for various organic substances, such as the homologous compounds of alkanes, esters, alcohols and aromatic compounds. It was also found that some aromatic positional isomers could be separated better on the PSOIL column than on the DB‐1 column. Furthermore, the stationary phase was suitable for separation of high‐boiling point compounds such as polycyclic aromatic hydrocarbons, phthalic esters, etc. All of these demonstrated that the PSOIL offered good selectivity and high separation efficiency for a wide range of analytes.     

Synthesis and characteristics of [60]fullerene polysiloxane stationary phase for capillary gas chromatography

A new type of fullerene-containing polysiloxane was synthesized by reacting [60]fullerene with azidopropyl polysiloxane directly. The polysiloxanes have been used successfully as stationary phases for capillary gas chromatography. They displayed high column efficiency, wide operational temperature and high thermostability, and exhibited unique selectivity for many organic substances, such as alkanes, alcohols, ketones and aromatic compounds. The stationary phase was especially suitable for separation of high boiling-point compounds like polycyclic aromatic hydrocarbons and phthalic esters, etc. It was also found that some alcoholic or aromatic positional isomers could be well separated on the column. The influence of the fullerene content on the separation was also investigated.     

Preparation and characterization of perhydroxyl-cucurbit[6]uril bonded silica stationary phase for hydrophilic-interaction chromatography

In this paper, perhydroxyl-cucurbit[6]uril ((HO)₁₂CB[6]) was, for the first time, grafted to silica gel as a hydrophilic-interaction chromatographic stationary phase. Several alkaloids were used as probes to investigate the retention mechanism on the new stationary phase. The effect of mobile phase variables such as acetonitrile content, ionic strength and pH on their chromatographic behavior was investigated. The results indicate that the stationary phase behaves as a hydrophilic-interaction chromatographic packing. Finally, several alkaloids were separated on the stationary phase.