新型亲水整体柱的制备及其在毛细管液相色谱和加压电色谱中的应用

以N,N-二甲基-N-甲基丙烯酰胺基丙基-N,N-二甲基-N-丙烷磺酸内盐(SPP)为单体,季戊四醇三丙烯酸酯(PETA)为交联剂,偶氮二异丁腈(AIBN)为引发剂及两类不同的致孔剂(乙醇/乙二醇和甲醇/1,4-丁二醇)制备了两种新型亲水性整体柱。为了获得理想的柱效、电渗流速度和渗透性,对制备整体柱的各反应物配比进行了研究和优化。比较了两种整体柱在渗透性和分离样品方面的性能,结果表明,以乙醇/乙二醇为致孔剂制备的整体柱在柱效、分离度方面优于以甲醇/1,4-丁二醇为致孔剂制备的整体柱,但在渗透性方面不及后者。探讨了流动相中盐浓度对核苷类样品保留的影响,发现当甲酸铵浓度从10 mmol/L增加到70 mmol/L时,核苷样品的保留因子呈现先增加后减小的状态。将制备的整体柱用于毛细管液相色谱和加压电色谱分别分离胺类、酚类和核苷类样品,获得了理想的分离效果。在分离酚类和核苷类混合样品时,发现加压毛细管电色谱在分离度和分离速度上均优于毛细管液相色谱。     

化学交联聚氯乙烯树脂的合成和结构

研究了氯乙烯/交联单体悬浮共聚时,交联单体种类、浓度和聚合温度对化学交联聚氯乙烯树脂结构的影响.对于氯乙烯/邻苯二甲酸二烯丙基酯(VC/DAP)悬浮共聚体系,凝胶含量和凝胶交联密度随DAP起始浓度的增加而增大;DAP浓度相同时,凝胶含量和凝胶交联密度随聚合温度上升而下降;当凝胶含量较高时,分子链物理缠结对凝胶交联密度有较大贡献,凝胶交联密度随凝胶含量增加而快速上升.在相同交联单体浓度下,氯乙烯/马来酸二烯丙基酯(VC/DAM)共聚物的凝胶含量最大,VC/DAP共聚物次之,氯乙烯/乙二醇二甲基丙烯酸酯(VC/EGDMA)共聚物最小,这是由于DAM单体的竞聚率小于1,且含有马来酸双键,EGDMA单体的竞聚率远大于1.     

Optimization of binary porogen solvent composition for preparation of butyl methacrylate monoliths in capillary liquid chromatography

Butyl methacrylate monolithic columns in 320 microm i.d. fused silica capillaries for reversed-phase capillary liquid chromatography were prepared by radical polymerization initiated thermally with azobisisobutyronitrile (AIBN). Polymerization mixture contained butyl methacrylate (BMA) as the function monomer and ethylene dimethacrylate (EDMA) as the crosslinking agent with 1,4-butanediol and 1-propanol as a binary porogen solvent. Ratio of 1,4-butanediol to 1-propanol in the porogen solvent was optimized regarding the monolithic column efficiency and performance. Total porosity, column permeability, separation impedance, Walters hydrophobicity index, retention factors, peak asymmetry factors, height equivalents to a theoretical plate and peak resolutions were used for characterization of the prepared monolithic columns. The polymerization mixture consisting of 17.8% of BMA, 21.8% of EDMA, 18.0% of 1,4-butanediol, 42.0% of 1-propanol and 0.4% AIBN generated monolithic columns of the best performance having a sufficient permeability and the lowest separation impedance. It was also demonstrated that monolithic columns of this composition exhibited good preparation reproducibility and an excellent pressure resistance when applied in capillary liquid chromatography.     

Preparation of thermostable,phenyl silicone coated,glass capillary columns for separation of polyaromatic hydrocarbons

Summary A procedure for the preparation of glass capillary columns coated with non-extractable phenyl polysiloxanes has been developed, the phenyl silicone being synthesised in situ in the column. The non-extractability can be explained in terms of a certain degree of crosslinking in the polymer and possibly also by some chemical bonding to the capillary glass wall. Rearrangement of the film at higher temperatures is counteracted by crosslinking in the phase. Column bleeding is thus decreased, and column efficiency is maintained even at higher temperatures. Such capillary columns showed suitable selectivities for separation of polyaromatic hydrocarbons, and the high temperatures necessary for these analyses could be attained.     

An investigation of the changes in column efficiency accompanying the oxidation of apolar gas chromatographic stationary phases

Summary The effect of on-column oxidation upon the efficiency of apolar gas chromatographic columns is investigated. With an unsaturated hydrocarbon liquid phase and air as carrier gas dramatic changes of column efficiency are observed. Evidence is presented that suggests that this catastrophic deterioration of column performance is due to the oxidative crosslinking of the liquid phase molecules.     

一种非晶硅膜改性弹性玻璃毛细管交联中等极性固定相色谱柱的制备

研究了非晶硅膜改性的弹性玻璃毛细管交联ＯＶ－１７０１中等极性固定相色谱柱。在适当温度下，采用过氧化二异丙苯（ＤＣＵＰ）游离基引发交联ＯＶ－１７０１固定液，成功地制备了交联ＯＶ－１７０１柱，该柱具有柱效高、惰性好、耐溶剂、抗腐蚀和耐高温等性能，是一种新型高性能的中等极性交联柱。     

Azo compounds for free radical crosslinking of polysiloxane stationary phases

There has been much effort spent in recent years developing the technology for free radical crosslinking of polysiloxane polymers to prepare capillary columns coated with thermally stable and nonextractable stationary phases. Organic peroxides have been used extensively as the free radical initiators for the in situ polymerization of the stationary phases. However, these peroxides adversely affect the phase polarity and column activity. Seven azo compounds were studied for crosslinking efficiency. Azo compounds can be used as free radical initiators to prepare nonextractable stationary phases without the adverse effects caused by peroxides.     

The preparation of non-extractable methylphenylpolysiloxane stationary phases for capillary column gas chromatography

Summary The synthesis of methylphenylpolysiloxane polymers and their use in the preparation of crosslinked, non-extractable stationary phases for fused-silica capillary columns are described. By preparing more viscous phenyl-containing polymers than are commercially available, stationary phase films of these polymers could be efficiently coated on fused-silica capillary columns and stabilized by a free radical crosslinking mechanism using peroxides. Four methylphenylpolysiloxane polymers containing different phenyl concentrations were prepared. These included three polymers containing 50% phenyl and one polymer containing 70% phenyl. Two of the 50% phenyl polymers had one phenyl and one methyl group attached to each silicon atom. One of these also had 1% vinyl incorporated. The third 50% phenyl polymer was synthesized in such a way that one half of the silicon atoms had two phenyl groups attached while the rest contained dimethyl groups. The 70% phenyl polymer also had 4% vinyl incorporated. Due to the intrinsic thermal stability of these phenyl phases and the enhanced film stability achieved by crosslinking, the 70% phenyl phase could be utilized up to 400 °C. Using the methods described in this paper, highly efficient and thermally stable fused silica capillary columns coated with crosslinked methylphenylpolysiloxane stationary phases can be successfully prepared.     

Preparation and evaluation of OV-240-OH coated glass capillary columns for isomer specific determination of PCDDs and PCDFs

Glass capillaries were leached, dehydrated, persilylated with 1, 3-bis (3-cyanopropyl) tetramethyldisiloxane, and coated with OV-240-OH. After crosslinking and binding the phase to the glass surface the columns showed high separation efficiency, high temperature stability, and inertness comparable to persilylated apolar columns. Column performance is shown to be superior to liquid phase cyanopropyl columns such as SP 2330. The excellent separation capabilities together with the selectivity of the phase makes OV-240-OH coated columns a valuable tool for the determination of toxic isomers in complex mixtures of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The order of elution of individual TCDD isomers was found to be similar to that described for SP 2330 or Silar 10c. The detection of PCDDs and PCDFs in a fly ash extract further illustrates the utility of OV-240-OH coated columns. The high temperature limit of these columns opens the way for the analysis of high boiling compounds such as mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans.     

光聚合整体式咖啡因印迹毛细管柱的制备及分离性能

分子印迹技术作为一种制备对目标分子具有专一识别能力的功能高分子的方法 ,近年来在化学化工、生物化学与生物技术的许多领域中得到广泛应用 [1～ 4 ] .分子印迹技术与微分离方法 (包括微柱液相色谱、毛细管电泳、毛细管电色谱和芯片分离等 )结合已引起人们极大的兴趣和关注[5,6] .毛细管柱是毛细管电色谱和微柱液相色谱的关键部件 ,目前普遍使用的是烷基键合硅胶微粒的填充柱 ,存在制备时须烧塞和填充两大困难 ,以及使用时易产生气泡和易折断等缺点 .将含被识别分子 (印迹分子 )、交联剂、溶剂、功能单体和引发剂的混合液注入毛细管 ,经光…