原位聚合那格列奈分子印迹手性固定相的分子识别特性研究

以手性药物那格列奈为模板分子,采用原位聚合法制备了具有特定识别性能和手性拆分能力的分子印迹聚合物,并用作高效液相色谱固定相实现了那格列奈与其对映体的手性拆分．通过静态结合方法考察了该聚合物的选择结合能力,并讨论了手性分离过程中的热力学性质．结果表明,原位聚合法制备的棒状聚合物固定相对模板分子及其对映体有很好的手性拆分性能．     

马拉硫磷分子印迹聚合物的制备及其在固相萃取中的应用

以马拉硫磷为模板分子,采用原位逐步聚合法制备了具有良好识别性能的分子印迹聚合物(MIPs),考察了马拉硫磷、甲基对硫磷、对硫磷及甲胺磷在马拉硫磷聚合物的选择性分离富集特性。用聚合物固相萃取了蜂蜜、蔬菜和天然水中的马拉硫磷。结果表明,聚合物对模板分子产生了印迹效应,对马拉硫磷有明显的选择性。流速为1.0 mL/min,进...     

单分散N-苯甲氧羰基-L-色氨酸表面分子印迹聚合物的手性拆分

采用多步溶胀与悬浮聚合联用的方法,以2-乙烯基吡啶(2-VP)为功能单体,二乙二醇二丙烯酸醋(DEGDA)为交联剂制备出N-苯甲氧羰基-L-色氨酸(N-Cbz-L-Trp)为模板的单分散分子印迹聚合物。高效液相色谱表征显示,制备的单分散分子印迹聚合物在很短的色谱柱中就能够实现对模板分子对映异构体的基线分离。以乙腈为流动相,进样量1000ng,流速0．25mL／min,柱温30℃时,该印迹聚合物对N-苯甲氧羰基-LD-色氨酸的分离度较好。     

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.     

分子印迹整体柱在高效液相色谱和电色谱手性分离中的应用

在常规不锈钢色谱管中以甲基丙烯酸为功能单体,采用原位聚合法制备了(5S,11S)-特罗格尔碱(S-TB)的印迹整体柱。考察了流动相中添加不同量的醋酸和水对分离的影响,结合台阶梯度洗脱模式在S-TB整体柱上实现了对TB消旋体的快速分离。另外,以碱性单体2-二甲基乙基胺甲基丙烯酸酯(DAMA)为功能单体,在毛细管中采用原位聚合法制备了毛细管分子印迹整体柱,用于在毛细管电色谱（CEC）中对消旋体1,1′-联-2-萘酚(BNL)进行手性分离。结果表明,以AMA为功能单体可以制备其他酸性模板的分子印迹聚合物,从而扩大了分子印迹聚合物MIP）在CEC分离中的应用范围。     

分子印迹整体柱在高校液相色谱和电色谱手性分离中的应用

在常规不锈钢色谱管中以甲基丙烯酸为功能单体,采用原位聚合法制备了(5S,11S)-特罗格尔碱(S-TB)的印迹整体柱.考察了流动相中添加不同量的醋酸和水对分离的影响,结合台阶梯度洗脱模式在S-TB整体柱上实现了对TB消旋体的快速分离.另外,以碱性单体2-二甲基乙基胺甲基丙烯酸酯(DAMA)为功能单体,在毛细管中采用原位聚合法制备了毛细管分子印迹整体柱,用于在毛细管电色谱(CEC)中对消旋体1,1'-联-2-萘酚(BNL)进行手性分离.结果表明,以DAMA为功能单体可以制备其他酸性模板的分子印迹聚合物,从而扩大了分子印迹聚合物(MIP)在CEC分离中的应用范围.     

电色谱模式下四肽印迹整体柱分子识别机理的研究

本文采用原位聚合法制备了以四肽YPLG为模板的毛细管分子印迹整体柱,在毛细管电色谱模式下以模板分子和它的结构类似物YPGL为样品,对分子印迹聚合物的识别机理进行了研究。这两种四肽由于化学结构相似且等电点非常相近,普通的电色谱和毛细管电泳方法分离非常困难。但我们的实验表明,印迹整体柱对模板分子具有特异性识别能力,因此YPLG与YPGL之间的分离因子为1.73,分离度达3.72。实验中系统地研究了流动相中有机溶剂的含量、缓冲溶液的pH值、缓冲溶液的盐浓度以及柱温对四肽识别的影响。实验中我们观察到模板在印迹柱上具有非线性的Van’t Hoff行为,揭示可能存在多重保留机理。本研究结果表明,在毛细管电色谱模式下,分子印迹整体柱的分子识别主要决定于样品与印迹聚合物之间的氢键作用以及印迹孔穴的三维结构。     

分子烙印聚合物为固定相分离和识别磺胺类药物

以磺胺甲噁唑为模板分子,采用原位聚合法制备了具有特定识别性能的棒状分子烙印聚合物。作为高效液相色谱的固定相实现了磺胺甲噁唑与其结构类似物的分离。磺胺甲噁唑烙印聚合物和目标分子之间的相互作用除了特异性的氢键作用外,也存在着疏水作用。同时考察含水量、流速对分离的影响,论证了分子烙印聚合物选择性专一的作用原理。结果表明,这种棒状聚合物对模板分子及其类似物有很好的分离能力。     

巴比妥分子印迹毛细管电色谱整体柱的制备及分离特性研究

以巴比妥为模板分子,采用原位聚合法制备了具有特定识别性能的巴比妥印迹聚合物.采用电色谱模式考察了该色谱柱的识别性能.结果表明:这种整体柱对模板分子有很好的识别能力.     

氨基安替比林MIP-CEC整体柱的制备及电色谱性能研究

以氨基安替比林为模板分子,在内径100 μm的石英毛细管内采用原位聚合法制备了分子印迹毛细管整体柱,以电色谱模式分离了氨基安替比林及其结构类似物安替比林,在乙腈(体积分数15%)-磷酸二氢钠缓冲液(5 mmol/L)作为流动相(pH 7.0)条件下,18 min内完成分离,分离因子为1.37.考察了缓冲液中乙腈含量、pH值、离子强度对电渗流、溶质保留时间及分离因子的影响,探讨了整体柱识别机理.     

Comprehensive two‐dimensional monolithic liquid chromatography of polar compounds

Two‐dimensional liquid chromatography largely increases the number of separated compounds in a single run, theoretically up to the product of the peaks separated in each dimension on the columns with different selectivities. On‐line coupling of a reversed‐phase column with an aqueous normal‐phase (hydrophilic interaction liquid chromatography) column yields orthogonal systems with high peak capacities. Fast on‐line two‐dimensional liquid chromatography needs a capillary or micro‐bore column providing low‐volume effluent fractions transferred to a short efficient second‐dimension column for separation at a high mobile phase flow rate. We prepared polymethacrylate zwitterionic monolithic micro‐columns in fused silica capillaries with structurally different dimethacrylate cross‐linkers. The columns provide dual retention mechanism (hydrophilic interaction and reversed‐phase). Setting the mobile phase composition allows adjusting the separation selectivity for various polar substance classes. Coupling on‐line an organic polymer monolithic capillary column in the first dimension with a short silica‐based monolithic column in the second dimension provides two‐dimensional liquid chromatography systems with high peak capacities. The silica monolithic C₁₈ columns provide higher separation efficiency than the particle‐packed columns at the flow rates as high as 5 mL/min used in the second dimension. Decreasing the diameter of the silica monolithic columns allows using a higher flow rate at the maximum operation pressure and lower fraction volumes transferred from the first, hydrophilic interaction dimension, into the second, reversed‐phase mode, avoiding the mobile phase compatibility issues, improving the resolution, increasing the peak capacity, and the peak production rate.     

高效液相色谱手性流动相添加法拆分阿卓乳酸对映体

采用C₁₈反相色谱柱,以磺丁基醚-β-环糊精（SBE-β-CD）作为手性流动相添加剂,建立了阿卓乳酸对映体的高效液相色谱拆分方法。考察了环糊精衍生物类型、手性添加剂浓度、流动相pH、流速和柱温对手性分离的影响,同时探讨了高效液相色谱采用磺丁基醚-β-环糊精分离阿卓乳酸对映体的分离机制及包结常数,确定了色谱条件为YMC-Pack ODS-A C₁₈色谱柱（250 mm×4.6 mm,5 μm）,流动相为含25 mmol/LSBE-β-CD的0.1 mol/L磷酸盐缓冲液（pH 2.68）-乙腈（90：10,v/v）,流速为0.6 mL/min,柱温为30 ℃,紫外检测波长为220 nm。对映体的保留时间分别为26.65和28.28 min,分离度为1.68。本方法分离度好,简便易行,且比使用手性固定相分离更加经济。     

阴离子交换整体柱对蛋白质的分离与纯化

分别用乙二胺、二乙胺、三乙胺将自制的以甲基丙烯酸缩水甘油酯(GMA)为单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂的整体柱修饰为弱、强阴离子交换整体柱。考察了该整体柱的性能,选择出分离蛋白质(牛血清白蛋白、溶菌酶和谷胱甘肽)的最佳实验条件,并在最佳分离条件下考察了这些蛋白质在整体柱上的色谱行为和该整体柱对纤维素降解酶的分离纯化情况。实验结果表明,该整体柱性能良好,可以实现对纤维素降解酶的快速分离与纯化。同时,实验也证明采用梯度洗脱可以实现对某些蛋白质的分离纯化。     

整体柱和填充柱离子对色谱-间接紫外检测法分析四乙基铵根离子

建立了整体柱离子对色谱-间接紫外检测和填充柱离子对色谱-间接紫外检测分析四乙基铵根离子的两种方法。用反相整体柱和反相填充柱,以咪唑离子液体-离子对试剂-有机溶剂为流动相,研究了背景紫外吸收试剂、检测波长、离子对试剂、有机溶剂、柱温和流速对测定四乙基铵根离子的影响,比较了两种色谱柱的差异,并讨论了保留规律。在优化的实验条件下,两种方法测定四乙基铵根离子的保留时间分别是2.40和3.02 min;检出限分别是0.04和0.07 mg/L;峰面积的相对标准偏差分别是0.16%和0.11%;保留时间的相对标准偏差分别是0.02%和0.01%。将这两种方法用于分析实验室合成的溴化四乙基铵离子液体,加标回收率分别为98.2%和99.1%。两种方法均能满足四乙基铵根离子测定的需要。     

三甲氧基苄啶分子印迹整体柱的制备及色谱性能

选择甲基丙烯酸为功能单体\, 甲基丙烯酸乙二醇双酯为交联剂, 制备了三甲氧基苄啶分子印迹整体柱, 对整体柱材料的形貌进行了表征, 并且研究了TMP和5种磺胺类药物在分子印迹整体柱上的色谱行为.     

弱阳离子交换整体柱的制备及其对人血浆中硝苯地平的在线分析

以甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,以色谱柱管为模具,通过原位聚合法制备了弱阳离子交换整体柱。该柱能去除血浆中的内源性物质,对生物样品中的药物有富集作用。将其作为固相萃取柱与C18色谱柱联用,在线分析了人血浆中的硝苯地平。流动相为甲醇-水(体积比为70∶30),流速1.0 mL/min,检测波长235 nm。结果表明,硝苯地平在5.0～75.0 μg/L范围内线性关系良好(r=0.9993),方法的回收率为90.0%～99.0%,日内、日间相对标准偏差均小于5.0%。该方法精密度高,重现性良好,避免了繁琐的样品预处理过程,且弱离子整体柱可多次重复使用,为检测血浆中的痕量药物提供了一种快速、经济、有效的新方法。     

Multisyringe Chromatography (MSC): An Effective and Low Cost Tool for Water-Soluble Vitamin Separation

The advent of monolithic columns has facilitated the combination of chromatographic techniques with nonseparation flow techniques by virtue of the low overpressure introduced by them. Thus far, these combinations have provided excellent results derived from the high selectivity of liquid chromatography and ease of sample handling in nonseparation flow techniques. The joint use of multisyringe flow injection analysis and monolithic columns has provided multisyringe chromatography (MSC).

Simultaneous spectrophotometric determination of ascorbic acid, nicotinic acid, nicotinamide, pyridoxine hydrochloride, thiamine hydrochloride, and riboflavin in commercial drinks using a MSC method, is described in this contribution as an inexpensive alternative to classical HPLC. The MSC method provides baseline separation of all these compounds with resolutions values greater than 2, except for B1 and B6 with resolution of 1,2.

A ChromolithTM Flash RP-18e (50 mm × 4.6 mm) column, a multisyringe burette provided with two 10 mL high-precision bidirectional syringes and an 8-port multiposition valve were used for a dual isocratic chromatographic separation in our study.     

Adsorption isotherms on nicotinamide-imprinted polymer stationary phase

The molecular-imprinted technique is applied for the preparation of a polymer selector by using methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as the cross-linker, 2,2'-azobisisobutyronitrile as the initiator, and nicotinamide as the template. The adsorption isotherms of nicotinamide and nicotinic acid and the competitive adsorption isotherms of nicotinamide and nicotinic acid on the imprinted stationary phase are determined using rectangular pulse frontal analysis and static method. Aqueous solution is used as the mobile phase in frontal analysis. It is found that the adsorption data fit well to both Langmuir and Freundlich isotherm models.     

Capillary Electrochromatography with Monolithic Poly(styrene‐co‐divinylbenzene‐co‐methacrylic acid) as the Stationary Phase

A new kind of monolithic capillary electrochromatography column with poly(styrene‐co‐divinylbenzene‐co‐methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically. The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed‐phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.     

Quantitative analysis of nicotinic acid, nicotinamide and 3-cyanopyridine in industrial effluent by high performance liquid chromatography

A rapid and reliable high performance liquid chromatographic (HPLC) method for the simultaneous determination of heterocyclic compounds, namely nicotinic acid, nicotinamide, and 3-cyanopyridine, in industrial effluent is described. A Φ4.6 mm × 150 mm, 5 μm C-18 reversed phase stationery phase, and a methanol-acetonitrile-water tertiary mobile phase (20:20:60 v/v) were used for separation. The detection wavelength of a diode array (DAD) was set at 216 nm with a bandwidth of 16 nm. Phenol was used as an internal standard. The regression equations revealed a linear relationship between the concentration of the analytes injected and the peak area detected by DAD. The limits of detection (S/N = 3) ranged from 0.70 to 1.18 mg L⁻¹, the recoveries ranged from 87% to 102% and the precision expressed as % RSD intra-day and inter-day varied from 0.9 to 3.9 and 1.2 to 5.6, respectively. This method is rapid, sensitive and suitable for the monitoring of nicotinic acid, nicotinamide, and 3-cyanopyridine in effluent of related pharmaceutical manufacturing plants.