高效毛细管电泳迁移重复性的考察

本文考察了高效毛细管电泳在强酸和强碱两种条件下分离二肽混和物的重复性,并且提出了采用相对迁移时间这一参数评估毛细管电泳的重复性。     

高效毛细管电泳迁移重复性的考察

 〕本文考察了高效毛细管电泳在强酸和强碱两种条件下分离二肽混和物的重复性，并且提出了采用相对迁移时间这一参数评估毛细管电泳的重复性。     

多肽在PEG-400交联改性电泳毛细管柱中的缓冲溶液浓度效应

在PEG-400交联柱上,用多肽样品研究了毛细管区带电泳中缓冲溶液浓度对迁移时间、柱效、选择性、分离度及进样量等的影响.发现试样的峰高与缓冲液浓度存在近似线性的关系,并随着浓度的增加而增大.对于电动进样模式,应注意毛细管内和进样槽里试样浓度的不一致性.     

几种标准蛋白质的毛细管区带电泳的分离及其迁移行为

本文采用毛细管区带电泳分离了几种标准蛋白,研究了不同的清洗方式,不同ＰＨ的缓冲溶液等对迁移行为及分离的影响,并同时考察了迁移时间和相对迁移时间与操作电压的关系。     

氨基酸衍生物在毛细管区带电泳下的分离研究

采用新合成的荧光试剂咔唑-9-乙基氯甲酸酯作为柱前衍生试剂,利用毛细管区带电泳法对衍生氨基酸进行分离,考察了该试剂用于毛细管区带电泳法进行氨基酸分离的关键条件,实现了12种氨基酸的快速基线分离.     

迁移时间归一化法改善毛细管电泳表征中药大黄的重现性

探讨了迁移时间归一化法改善中药毛细管电泳分析迁移时间重现性的原理,并将其应用于实际样品的分析。迁移时间归一化法认为,在相同的操作电压、缓冲液组成和温度条件下,多次电泳实验中迁移时间产生差别的主要原因是多次电泳实验中电渗流产生了差异。迁移时间归一化法就是通过选择电泳谱图中的一个或两个峰作为标记峰,将各次电泳实验的迁移时间都归一到第一次电泳实验中的迁移时间。比较多次电泳实验中迁移时间(t)的相对标准偏差(RSD)、经单峰归一化处理的迁移时间(t′)的RSD、经双峰归一化处理的迁移时间(t″)的RSD、迁移时间比(t/tistd,istd代表所选择的标记物)的RSD,发现RSD(t″)相似文献   

无机阴离子的CZE多波长同时测定

运用现代高效毛细管电泳仪HP~(3D)CE的卓越性能,研究了水中无机阴离子的毛细管区带电泳(CZE)多波长同时测定,并考察了分离电压、温度、pH值对电泳分离的影响.     

高效毛细管区带电泳分离亲水性(Gly)~n小肽

对毛细管区带电泳与反相液相色谱分离一组亲水性(Gly)~n 小肽选择性的差异作了对比,同时考察了小肽分子结构以及温度变化对小肽迁移行为的影响     

新型固定化pH梯度毛细管等电聚焦方法用于蛋白分离

通过化学键合建立一种固定化pH梯度的方法,用于毛细管等电聚焦分离蛋白质.采用微流控泵驱动毛细管内的聚焦区带,通过调节泵的流量,从而调节聚焦区带的迁移速度.该方法避免了自由溶液聚焦时两性电解质所带来的影响,实现了高灵敏度及检测波长自由选择等优点,适用于两步法毛细管电泳等电聚焦分离蛋白质等两性电解质.本文考察了对牛血清白蛋白和血红蛋白两种蛋白质混合物的分离,证明了该方法可行.     

高效毛细管区带电泳分离亲水性(Gly)~n小肽

对毛细管区带电泳与反相液相色谱分离一组亲水性(Gly)_n小肽选择性的差异作了对比,同时考察了小肽分子结构以及温度变化对小肽迁移行为的影响。     

Capillary electroendoosmotic chromatography of peptides

This review focuses on the current state of peptide separation by capillary electroendoosmotic chromatography (CEC). When carried out under optimised conditions, peptide separation by CEC methods represents an orthogonal and complementary technique to micro-HPLC (micro-HPLC) and high-performance capillary zone electrophoresis (HPCZE). The origin of the selectivity differences that can be achieved with these three separation techniques (CEC, micro-HPLC and HPCZE), respectively are discussed, and the current limits of performance with CEC methods documented. Peptide separations by CEC methods with n-alkyl bonded silicas or mixed-mode phases are also illustrated. The development of different variants of CEC and pressurised CEC (also commonly referred to in the literature as electrically-assisted micro-HPLC) are examined. The potential of coupling CEC systems to mass spectrometers for real-time analyses of peptides or protein digests has been examined. Several future directions for the application of this technique in phenotype/proteomic and zeomic mapping of naturally occurring peptides and proteins are highlighted.     

Studies on the relationship between structure and electrophoretic mobility of alpha-helical and beta-sheet peptides using capillary zone electrophoresis.

The electrophoretic behaviour of a series of 33 different synthetic peptides has been investigated using free solution high-performance capillary zonal electrophoretic (HPCZE) methods. The dependency of the electrophoretic mobility, mu(em), on the peptide charge, q, and on the charge-to-size ratio parameter, zeta, determined according to several electromobility models, have been examined. Significant divergences from linearity in the mu(em) vs. q or the mu(em) vs. zeta plots were noted for several peptides, possibly due to the proclivity of specific arrangements of their amino acid sequences to assume preferred alpha-helical or beta-sheet conformational features rather than random coil structures under the HPCZE conditions. These results provide further demonstration of the facility of HPCZE procedures to probe the effects of compositional, sequential and conformational differences of closely-related peptides and their consequences on their physicochemical behaviour in solution.     

Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser-induced fluorescence detector

A capillary electrophoresis immunoassay (CEIA) was developed for the determination of trace metolcarb (MTMC) in food. The method was based on the competitive reactions between fluorescently labeled MTMC tracer and free MTMC with a limited amount of anti-MTMC antibody and the separation and determination by CE with LIF detector. A fluorescent reagent, FITC was labeled on MTMC to construct an immunofluorescent probe. CEIA experimental parameters such as the pH value and concentration of the running buffer and separation voltage as well as incubation time were systematically investigated. Under the optimized conditions, fluorescently labeled antigen and antibody bound could be well separated within 3 min using Na?B?O?/NaH?PO? buffer (20:10 mmol/L, pH 9.0) for background electrolyte, 20 kV for the separation voltage, and 20°C for the column temperature. The linear range of the method was 0.25-50.0 μg/L with LOD 0.07 μg/L. The RSD for relative migration time and relative fluorescence intensity ratio were 2.90% (intraday) and 4.73% (intraday), respectively. The proposed method has been applied to determine the residue of MTMC in food samples with the satisfactory recovery.     

Separation of peptides by strong cation-exchange capillary electrochromatography

Separation of small peptides on ion-exchange capillary electrochromatography (IE-CEC) with strong cation-exchange packing (SCX) as stationary phase was investigated. It was observed that the number of theoretical plates for small peptides varied from 240000 to 460000/m, and the relative standard deviation for t0 and the migration time of peptides were less than 0.57% and 0.27%, respectively for ten consecutive runs. Unusually high column efficiency has been explained by the capillary electrophoretic stacking and chromatofocusing phenomena during the injection and separation of positively charged peptides. The sample buffer concentration had a marked effect on the column efficiency and peak area of the retained peptides. The influences of the buffer concentration and pH value as well as the applied voltage on the separation were investigated. It has been shown that the electrostatic interaction between the positively charged peptides and the SCX stationary phase played a very important role in IE-CEC, which provided the different separation selectivity from those in the capillary electrophoresis and reversed-phase liquid chromatography. A fast separation of ten peptides in less than 3.5 min on IE-CEC by adoption of the highly applied voltage was demonstrated.     

冻干粉针用溴化丁基胶塞中溴化物的迁移及安全性评价

建立了对溴化丁基胶塞中溴化物的提取方法,考察了胶塞中溴化物在冻干粉中的浸出水平. 采用IonPac AS 11-HC色谱柱(4.0 mm×250 mm)和IonPac AS 11-HC保护柱(4.0 mm×50 mm),24 mmol/L KOH淋洗液等度洗脱,AERS 500(4 mm)阴离子抑制器及电导检测器,抑制器电流60 mA,柱温30 ℃,流速1.0 mL/min. 溴化物在0.2~10.0 mg/L浓度范围内线性关系良好(r＝0.999 9),检出限(LOD)为0.007 mg/L. 冻干粉针用溴化丁基胶塞以30%异丙醇水溶液为提取溶剂,80 ℃下保持7 h后测定提取液中溴化物含量. 冻干粉采用超纯水复溶后直接测定溴化物迁移量,迁移试验平均回收率为98.1%~104.3%,相对标准偏差(RSD,n=6)为2.9%~4.3%. 方法可用于包材相容性研究中实际样品的检测.     

直热式毛细管柱对直馏汽油组成的分析

采用柱内电阻丝加热升温的直热式１３Ｘ分子筛薄层毛细管填充柱分析汽油的族组成。分析时间比炉温加热短５０ｍｉｎ,定量分析结果与炉温加热和多孔层开管柱基本相同。保留时间的相对偏差小于３％,直馏汽油中绝大部分组分定量结果的相对偏差小于５％。     

Determination of tetraethyl ammonium by ion-pair chromatography with indirect ultraviolet detection using 4-aminophenol hydrochloride as background ultraviolet absorbing reagent

A method was developed for the determination of tetraethyl ammonium (TEA) by reversed-phase ionpair chromatography with indirect ultraviolet detection. Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 μmol/L 4-aminophenol hydrochloride and 0.15 μmol/L 1-heptanesulfonic acid sodium mixed with 20% (v/v) methanol asmobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit (S/N = 3) for TEA was 0.06 mg/L. The relative standard deviations (n = 5) for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.     

离子色谱法同时分析离子液体中三氟乙酸根、四氟硼酸根和三氟甲烷磺酸根

建立了离子色谱-直接电导检测法同时测定离子液体中三氟乙酸根、四氟硼酸根和三氟甲烷磺酸根的方法。色谱分离采用Shim-packIC-A3阴离子交换色谱柱和邻苯二甲酸氢钾淋洗液。最佳色谱条件为:以邻苯二甲酸氢钾(1.2mmol/L)为淋洗液,柱温30℃,流速1.0mL/min。在此条件下,所测阴离子的检出限为0.06～3.07mg/L,保留时间和峰面积的相对标准偏差(n=5)分别不大于0.18%和1.62%。用来测定离子液体中三氟乙酸根、四氟硼酸根和三氟甲烷磺酸根,加标回收率为98.2%～101.8%,能够满足离子液体中的三氟乙酸根、四氟硼酸根和三氟甲烷磺酸根定量分析要求。     

Controlling the retention in capillary LC with solvents, temperature, and electric fields

Once a suitable stationary phase and column dimensions have been selected, the retention in liquid chromatography (LC) is traditionally adjusted by controlling the mobile phase composition. Solvent gradients enable achievement of good separation selectivity while decreasing the separation time as compared to isocratic elution. Capillary columns allow use of other programming parameters, i.e. temperature and applied electric fields, in addition to solvent gradient elution. This paper presents a review of programmed separation techniques in miniaturized LC, including retention modeling and method transfer from the conventional to micro- and capillary scales. The impact of miniaturized instrumentation on retention and the limitations of capillary LC are discussed. Special attention is focused on the gradient dwell volume effects, which are more important in micro-LC techniques than in conventional analytical LC and may cause significant increase in the time of analysis, unless special instrumentation and (or) pre-column flow-splitting is used. The influence of temperature upon retention is also discussed, and applications where the temperature has been actively used for retention control in capillary LC are included together with the instrumentation utilized. Finally the possibilities of additional selectivity control by applying an electric field over a packed capillary LC column are discussed.