亲和毛细管整体柱在牛血清白蛋白与奈福泮对映体相互作用研究中的应用

利用胃蛋白酶键合的有机聚合物整体柱在电色谱中对手性药物奈福泮的拆分能力,采用前沿分析法同时对奈福泮的两个对映体与牛血清白蛋白(BSA)的相互作用情况进行了考察。经过优化后建立的电色谱条件为:胃蛋白酶修饰的聚(甲基丙烯酸环氧丙酯-乙二醇二甲基丙烯酸酯)毛细管整体柱作为分离通道(32 cm×75 μm,有效长度22 cm),运行缓冲液为pH 5.5的15 mmol/L醋酸铵,样品溶剂为pH 7.4的50 mmol/L醋酸铵,运行电压为5.0 kV,电压进样10 kV×6 s,检测波长为215 nm。此时奈福泮两个对映体平台峰彼此完全分离,结合体系中BSA对对映体在电色谱中的分离和检测均无影响,测得两个对映体与BSA的结合常数分别为443和527 L/mol,结合位点数均为1.0,结合位点为Sudlow site Ⅱ。     

聚合物整体柱管内固相微萃取-高效液相色谱在线联用测定血浆中的氟喹诺酮类药物

 目的建立一种聚(甲基丙烯酸-乙二醇二甲基丙烯酸酯)[P(MAA-co-EGDMA)]毛细管整体柱管内固相微萃取与高效液相色谱在线联用测定血浆中5种氟喹诺酮类药物的方法。方法本实验系统优化了5种氟喹诺酮类药物在P(MAA-co-EGDMA)整体柱上的萃取条件,选用25mmol·L^-1磷酸盐缓冲液(pH4.1)为固相微萃取携带液;解吸液及流动相均为25mmol·L^-1磷酸盐缓冲液(pH2.1)-甲醇-乙腈(72∶20∶8);流速分别为0.04及1.0mL·min^-1;检测波长为280nm。结果建立的管内固相微萃取与高效液相色谱在线联用,在预处理和测定血浆中的5种氟喹诺酮类药物时,无基质干扰现象,线性关系r>0.9995,日内、日间精密度RSD<7%,检测限为1.1～2.6μg·L^-1。结论作为一种将样品的预处理及预富集与色谱分离检测在线联用的新方法,该方法对环境污染小,能够简便快速、准确及高灵敏度地检测血浆等生物样品中的药物含量。     

Challenges and Strategies in the Synthesis of Mesoporous Alumina Powders and Hierarchical Alumina Monoliths

A new rapid, very simple and one-step sol-gel strategy for the large-scale preparation of highly porous γ-Al₂O₃ is presented. The resulting mesoporous alumina materials feature high surface areas (400 m² g⁻¹), large pore volumes (0.8 mL g⁻¹) and the γ-Al₂O₃ phase is obtained at low temperature (500 °C). The main advantages and drawbacks of different preparations of mesoporous alumina materials exhibiting high specific surface areas and large pore volumes such as surfactant-nanostructured alumina, sol-gel methods and hierarchically macro-/mesoporous alumina monoliths have been analyzed and compared. The most reproducible synthesis of mesoporous alumina are given. Evaporation-Induced Self-Assembly (EISA) is the sole method to lead to nanostructured mesoporous alumina by direct templating, but it is a difficult method to scale-up. Alumina featuring macro- and mesoporosity in monolithic shape is a very promising material for in flow applications; an optimized synthesis is described.     

Rapid fabrication of zwitterionic sulfobetaine vinylimidazole-based monoliths via photoinitiated copolymerization for hydrophilic interaction chromatography

Zwitterionic sulfobetaine-based monolithic stationary phases have attracted increasing attention for their use in hydrophilic interaction chromatography. In this study, a novel hydrophilic polymeric monolith was fabricated through photo-initiated copolymerization of 3-(3-vinyl-1-imidazolio)-1-propanesulfonate (SBVI) with pentaerythritol triacrylate using methanol and tetrahydrofuran as the porogenic system. Notably, the duration for the preparation of this novel monolith was as little as 5 min, which was significantly shorter than that required for previously reported sulfobetaine-based monoliths prepared via conventional thermally initiated copolymerization. Moreover, these monoliths showed good morphology, permeability, porosity (62.4%), mechanical strength (over 15 MPa), column efficiency (51,230 plates/m), and reproducibility (relative standard deviations for all analytes were lower than 4.6%). Mechanistic studies indicated that strong hydrophilic and negative electrostatic interactions might be responsible for the retention of polar analytes on the zwitterionic SBVI-based monolith. In particular, the resulting monolith exhibited good anti-protein adhesion ability and low nonspecific protein adsorption. These excellent features seem to favor its application in bioanalysis. Therefore, the novel zwitterionic sulfobetaine-based monolith was successfully employed for the highly selective separation of small bioactive compounds and the efficient enrichment of N-glycopeptides from complex samples. In this study, we prepared a novel zwitterionic sulfobetaine-based monolith with good performance and developed a simpler and faster method for preparation of zwitterionic monoliths.     

In Situ One‐Step Method for Synthesis of “Click”‐Functionalized Monolithic Stationary Phase for Capillary Electrochromatography

Propargyl acrylate‐based functionalizable monolithic stationary phase (FMSP) for capillary electrochromatography, easily modifiable by alkyne–azide 1,3‐dipolar cycloaddition, is developed. Optimization of FMSP is focused on (i) physical properties: rigidity, stability, and pore size and (ii) the ease of capillary preparation and grafting. The effect of grafting is demonstrated on the separation of eleven polycyclic aromatic hydrocarbons (PAHs), three flavonols, and chlorpheniramine before and after derivatization. Two azides are synthesized: the first, cinnamyl azide increases the retention of PAHs and improves separation of flavonols, the second, 6‐azido‐6‐deoxy‐β‐cyclodextrin allows the chiral separation of warfarin, improves the efficiency of PAHs separation and increases retention of chlorpheniramine.     

Porous Poly(styrene‐co‐divinylbenzene) Neutral Monolith: From Design and Characterization to Reversed‐Phase Capillary Electrochromatography Applications

Macroporous cross‐linked organic polymers, based on styrene and divinylbenzene (PS‐DVB), are prepared as monolithic stationary phases for capillary electrochromatographic applications. The synthetic strategy, which relies on the semi‐interpenetrating polymer network (semi‐IPN) approach, is performed through UV‐initiated free radical copolymerization of the comonomers in the presence of poly(?‐caprolactone) (PCL) within the confines of fused silica capillaries. The characterization of PS‐DVB monoliths is carried out at the different stages of the synthesis using a combination of experimental techniques, thus providing information on the chemical and porous structures. All experimental results evidence the sole role of the PCL oligomer as a porogen.     

纳米碳纤维/蜂窝状堇青石催化剂载体的结构控制

以Ni为催化剂、乙烯作碳源,制备了纳米碳纤维/蜂窝状堇青石催化剂载体,并考察了制备工艺对所制纳米碳纤维(CNFs)产率及形貌的影响。结果表明：当生长温度从450 ℃升至650 ℃时,CNFs的产率先增加后降低;当生长时间由5 min延长至30 min时,CNFs的产率从4.9%提高到12.5%,随着生长时间的进一步延长,增长趋于平缓;较高的C2H4/H2流量比有利于提高CNFs的产率;在500 ℃、30 min、VC2H4∶VH2=160∶40的最佳工艺条件下,CNFs的产率及所制载体的压缩强度分别达12.5%和34.46 MPa。     

Unique Transitions in Morphology and Characteristics of Porous Poly(Lactic Acid) Enantiomers

This study examines unique changes in the morphology and physical properties of monolithic poly(lactic acid) (PLA) enantiomers. It is revealed for the first time that PLA monoliths containing stereocomplex (sc) crystals are successfully produced using enantiomeric poly(L‐lactic acid) (PLLA) and poly(D‐lactic acid) (PDLA) using a simple phase separation process with ternary solvent (1,4‐dioxane/2‐butanone/water). The basic structure of the monoliths is changed drastically from needle‐like to spherical morphology until reaching a PLLA/PDLA ratio to equivalence. The PLA monolith prepared from a stoichiometric amount of PLLA/PDLA has high sc crystallinity without any homochiral crystals, and it shows higher melting temperature (226 °C), surface area (131 m² g^?1), and water contact angle (144.5°) compared with those of neat PLLA (180 °C, 86 m² g^?1, and 137.5°, respectively). Moreover, this sc‐PLA monolith exhibits excellent resistance to several good solvents of PLLA, whereas the pristine PLLA monolith is dissolved instantly in these solvents.     

Thiol–Maleimide Michael Addition Click Reaction: A New Route to Surface Modification of Porous Polymeric Monolith

A new and efficient approach based on the thiol–maleimide Michael addition click reaction is presented for the post‐polymerization modification of porous monoliths. To establish the method, a generic matrix containing N‐hydroxysuccinimide esters (NHS) as surface reactive units is synthesized inside a capillary column through photoinduced polymerization of N‐acryloxysuccininimide and ethylene glycol dimethylacrylate. The as‐obtained reactive monolith is further surface‐functionalized through nucleophilic substitution of the NHS units with 2‐aminoethanethiol. Following such an approach, free thiols are available for reacting with functional maleimides through Michael addition. Success of the successive molecular level surface functionalization steps is ascertained by Raman spectroscopy measurements. Of utmost importance, it is undoubtedly demonstrated that the chemical nature, i.e., hydrophilic versus hydrophobic, of the surface‐grafted maleimide governs the surface properties of the corresponding monoliths. More precisely, the electrochromatographic separation mode is found to be intimately correlated to the chemical nature—C8‐like versus COOH‐like—of the maleimide‐functionalized monolith allowing separation upon either reversed‐phase or hydrophilic interaction modes, respectively. Furthermore, the strategy is extended to enhancement of surface NHS reactivity enabling the efficient grafting of model biomacromolecule via a spacer arm‐driven effect.

     

几种蝶呤类药物的毛细管电色谱分析研究

目的建立几种蝶呤类药物的毛细管电色谱分离方法。方法制备了十八烷基中性毛细管整体柱,应用于蝶呤类药物的毛细管电色谱分离。结果在最优条件下(乙腈-缓冲液∶40∶60,甲酸胺缓冲液pH=6.5,8mmol.L-1;分离电压-15kV),实现了蝶呤类药物在中性整体柱上的分离。结论毛细管电色谱技术对蝶呤类药物分离方法简单,效果良好。