High Performance Liquid Chromatography Separations Using Short Columns Packed with Spherical ODS Particles. II. Effect of Mobile Phase Composition on Resolution

Abstract

The effect of instrumental parameters, mobile phase composition, and flow rate on high performance liquid chromatography separations using 3 cm, 5 cm, and 10 cm columns packed with 3y spherical ODS materials is discussed. The results indicate that when instrumental parameters were optimized, the 10 cm column gave better separation than the shorter columns under the same experimental conditions. However, when the mobile phase composition was adjusted so that the solute residence time was comparable in the three columns, short and long columns gave comparable results.     

High Performance Liquid Chromatography Separations Using Columns Packed with Spherical ODS Particles. III. Effect of Column Dimensions on the Resolution of a Complex Mixture

Abstract

Separations on short columns, (3 and 5 cm, packed with 3 μ ODS spherical materials) and somewhat larger ones (10 cm and 20 cm columns having 2.1 mm and 4.6 mm diameters packed with 5 μ ODS spherical materials) were compared using Aroclor 1254. With simple mixtures, the results showed that short columns can give separations comparable with those on longer columns when the percentage of the organic modifier in the mobile phase is adjusted. This was not so with more complex mixture. The results also showed that columns which have a comparable volume do not produce comparable separation. The longer column, 200 mm × 2.1 mm gave better resolution than the shorter 50 mm × 4 mm column. Also a shorter column, (100 mm × 4.6 mm), which had double the volume of a longer column. (200 mm × 2.1 mm), gave better resolution of the Aroclor 1254 test solution.     

高效液相色谱整体柱技术的进展

高效液相色谱整体柱（又名连续床）具有制备相对简单、原料易得以及聚合组分在一定范围内可调节的优点,是近年来得到迅速发展的新型色谱柱。本文综述了目前高效液相色谱（HPLC）制备整体柱的典型高聚物体系、制备各种整体柱时反应条件的影响,并简要介绍了它的表征方法和应用。     

Separations in Thin Layer and High Performance Liquid Chromatography Using Alkyl Silica Gel Bonded Phases

Abstract

Separations in thin layer (TLC) and high performance liquid chromatography (HPLC) using alkyl bonded phases were carried out under optimum solvent conditions for each of three phases, RP-2, RP-8 and RP-18. The phases were tested for their efficiency and resolving power using three groups of compounds in three binary organic-water mobile phases. The organic solvents were acetonitrile, methanol and tetrahydrofuran, which are widely used as solvent modifiers in reversed phase liquid chromatography.

The results showed that, unlike HPLC, TLC using RP-18 plates was the most, and RP-2 plates the least, efficient. A naphthalene and biphenyl mixture which was resolved by HPLC using any of the three solvents and columns was not resolved by TLC using any plate or solvent combination, unless the plate was prewashed with an organic modifier. The addition of NaCl (1–2% wt/vol) to the solvent for TLC speeded development unless an alcohol was used, but did not greatly affect the separation.     

Preparation of High Efficiency Columns for High Performance Liquid Chromatography

Abstract

This method employs a specially constructed slurry reservoir, which features an internal taper and a quick-disconnect pump fitting. A major innovation is the use of a three-solvent system to maintain a slurry of packing material as a ‘slug’ within the reservoir. A measured amount of carbon tetrachloride is poured into the empty reservoir-column assembly. The column packing material is introduced as an isopropanol slurry and the reservoir is filled with isooctane. The assembly is then connected to a Haskel DSTV 122C pump, and the column is packed with isooctane at 10,000 psi pressure.

This procedure provides HPLC columns with efficiencies of 40,000 plates per meter for 10-micron silica, 30,000 plates per meter for 10-micron C₁₈, and 70,000 plates per meter for 5-micron C₁₈ packing materials. We have used this method for preparation of over 35 HPLC columns during the past two years.     

填充毛细管液相色谱-毛细管气相色谱在线联用技术

建立了一套填充毛细管液相色谱－毛细管气相色谱在线联用的二维色谱分离体系。联用接口由十通阀和多位阀构成，将经填充毛细管液相色谱分离后的样品各馏分在线准确切割和储存，并在线无损失输送至ＧＣ分析，从而实现了复杂样品的一次进样全组分的分离分析。     

不锈钢宽口径填充毛细管液相色谱柱的制备及评价

设计了一种零死体积的柱尾连接方式和一种能使匀浆填料均匀进入色谱柱管内的锥形储料池。详述了以反相 ＯＤＳ为固定相,制备高效稳定的不锈钢宽口径（０．８ ｍｍＩ．Ｄ．）填充毛细管液相色谱柱的方法。系统地考察了填装方向、加压溶剂、匀浆溶剂、匀浆浓度和填装压力等不同因素对柱效的影响。在４０ＭＰａ压强和优化条件下,可重复制得柱效达理论塔板数为７．５×１０４／ｍ。对所测试的样品,色谱峰不对称因子为１．０３～１．１０。     

High Performance Liquid Chromatography Separations of Nitrosamines. I. Cyclic Nitrosamines

Abstract

The separation of cyclic nitros amines by HPLC was achieved using a cyclobond I column and a mobile phase of methanol/water. The effect of in-the-ring and on-the-ring substitutions on retention times were studied. The results show that the longer the chain of the substituent, the longer the retention time, which is consistent with the inclusion mechanism of separation. Also, the larger the ring, the longer the retention time. The results also show that the in-the-ring substitution has a dramatic effect on retention.     

A New Spherical Hydroxyapatite for High Performance Liquid Chromatography of Proteins

Abstract

Basic properties of a newly developed hydroxyapatite column and results of its application to the separation of proteins are described. The hydroxyapatite was completely spherical and porous beads in appearance by scanning electron microscopy, and showed superior properties to other types of hydroxyapatite column. The column was mechanically strong enough to show the pressure limit of 140–150 kg/cm². The hydroxyapatite column showed excellent mechanical and chemical stability, and was applicable to high speed and high resolution separation of proteins. Proteins are recovered in high yield after the chromatography.     

基于微机电子系统技术高性能气相色谱柱的制备

基于微机电系统(Micro-electro-mechanical systems,MEMS)技术,制作了微型气相色谱柱,并对其性能进行了研究。与传统色谱柱相比,此微型色谱柱具有体积小,分析速度快等特点,适用于在线检测分析与监测。本研究利用深刻蚀技术与动态涂覆固定相的方法,设计制作了0.5,1.0及3.0 m色谱柱,实现了对苯,甲苯和邻二甲苯的分离。其中,3.0 m色谱柱对甲苯和邻二甲苯的分离度达14.3,理论板塔数达6160,分离时间少于200 s。考察了柱长对色谱柱分离性能的影响。此微型色谱柱可广泛应用于家居安全,瓦斯监测以及环境检测等领域。     

High Performance Liquid Chromatography of Mouse Monoclonal Antibodies on Spherical Hydroxyapatite Beads

Abstract

High performance liquid chromatography (HPLC) on newly developed spherical beads of hydroxyapatite was applied for the simple purification of monoclonal antibodies (mAbs) secreted into mouse ascitic fluid. Sixteen mAbs including all four subclasses of IgG and IgM were separated successfully from serum albumin a major contaminant in the crude mAb preparation by a 30 min-linear gradient of phosphate ion concentration from 0.01M-0.3M at pH 7.2. Not only IgG mAbs but also IgM mAbs were quantitatively eluted from the column. Each antibody had a different retention time (apparent capacity factor of 2.24–4.14) in the chromatography and no relation was found between the retention time and the type of immunoglobulin (class or subclass). A monomeric form of IgM was also resolved successfully from IgM (pentamer) after its reduction with dithiothreitol; the monomer form of IgM was eluted from the column by a lower concentration of phosphate ion than was the pentamer. These results indicate that HPLC on the hydroxylapatite beads will be useful for the purification and characterization of mouse mAbs.     

Assay of Brain Tocopherols Using High Performance Liquid Chromatography

Abstract

The four natural tocopherols were separated using a μ-Bondapak-NH₂ column. For the analysis of brain tocopherols 5,7-dimethyltocol was used as an internal standard. α-Tocopherylquinone and other tocopherols than α-tocopherol were not detected. Rat cerebral cortex and cerebellum contained 19.3 μmol/g and 11.2 μmol/g of α-tocopherol, respectively. A chromatographic system with a reversed-phase column proved less suitable.     

台锥形柱尾的填充毛细管液相色谱柱

首次将台锥形柱尾用于填充毛细管液相色谱柱,并与环氧胶粘的柱尾连接方式进行比较,发现在柱内径≥０．３２ｍｍ时,前者的柱效比后者高出３０％～５０％,且明显改善柱效－流速特性。对比研究了不同内径柱（０．５３ｍｍ,０．３２ｍｍ,０．２５ｍｍ）采用两种尾接方式的塔板高度与流速的关系,对产生差异的原因进行了探讨。     

高效液相色谱的4种商品手性柱对38种手性化合物的拆分研究

采用纤维素-三(3,5-二甲基苯基氨基甲酸酯)涂敷型手性固定相(Chiralcel OD柱)、直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)涂敷型手性固定相(Chiralpak AD柱)、直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)键合型手性固定相(Chiralpak IA柱)和Pirkle型的(S,S)-Whelk-01手性固定相对38种外消旋体化合物进行手性拆分。实验结果表明,4种固定相的手性识别能力为:OD>AD>IA>(S,S)-Whelk-01,OD固定相的手性识别率达到60%,并且它们之间的手性识别性能还具有一定的互补性。本研究对4种常用手性固定相的拆分能力进行了对比,为拆分手性化合物时有的放矢地选择手性固定相提供了参考。     

Mechanistic Principles in Chiral Separations Using Liquid Chromatography and Capillary Electrophoresis

Due to the importance of chiral separations of drugs, pharmaceuticals, agrochemicals and xenobiotics by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), it is important to have the knowledge of the enantiomeric recognition mechanisms so that scientists may design and module the new chiral selectors for rapid, inexpensive and reproducible chiral separations; specially at preparative scale. The mechanisms of the chiral separation by HPLC and CE using polysaccharides, cyclodextrins, macrocyclic glycopeptide antibiotics, Pirkle type, ligand exchangers, crown ethers and other several types of chiral selectors have been discussed. Various complex formation and different types of interactions responsible for chiral resolution have been presented in detail.     

Determination of Amphotericin-B in Human Plasma by Reversed-Phase High Performance Liquid Chromatography Using a Short Octyl Column

Abstract

Amphotericin-B is a polyene antifungal antibiotic used for the treatment of severe systemic fungal infections. For effective treatment of urinary fungaria and the prevention of significant adverse-effects, monitoring the concentration of Amphotericin-B in biological samples of humans (ingesting the drug) is required. In this experiment, Amphotericin-B was isolated from plasma endogenous substances by adding 200 μL of acetonitrile in 800 μL of plasma. This mixture was vortex mixed, 20 mg of zinc sulfate and 10 mg of monobasic potassium phosphate was added to the mixture. This mixture was again vortex mixed and followed by centrifugation. The supernatant was filtered through a 0.45 μm membrane and a 100 μL aliquot of this solution was injected onto the chromatographic system. A short column of 60 mm × 4.6 mm packed with 3 μm octyl particles was used with an isocratic elution of 50/50, acetonitrile/0.01M KH₂PO₄ (v/v). The pH of the mobile phase mixture was adjusted to 3.5 with H₃PO₄. The intact drug molecule (parent drug) was monitored by a W-visible detector at 410 nm and 0.10-0.005 A.U.F.S. The limits of detection of the method were 0.03 μg/mL for 100 μl injection volume at signal-to-noise ratio of 3.     

高效液相色谱法测定复方芦丁片中芦丁和维生素C的含量

采用反相高效液相离子对色谱法,以对氨基苯甲酸为内标,测定了复方芦丁片中芦丁和维生素Ｃ的含量。色谱柱为μ－ＢｏｎｄａｐａｋＣ_（１８）,流动相为甲醇－水（５０：５０）配制的樟脑磺酸溶液（０．００２５ｍｏｌ／Ｌ）,检测波长为２５４ｎｍ。并做了线性范围和回收率测定。     

Rapid Assay of Hypothalamic Aromatase Using High Performance Liquid Chromatography

Abstract

A rapid assay for hypothalamic aromatase has been developed using HPLC. Each assay tube contained rat anterior hypothalamus homogenized in Na phosphate buffer (pH 7.0), NADPH regenerating system, unlabelled estradiol and estrone, and 10 μCi of ³H-androstenedione. After agitation at 37°C for 3 hours, the reaction mixture was extracted with CH₂Cl₂, partitioned between 90% methanol and hexane, and the methanol layer chromatographed on a Waters 10μ C-18 Radial-PAK column using acetonitrile/water (70:30). The estrogens were collected together and rechromatographed with THF/water (35:65). The estrone peak was collected, and the ³H-estrone produced was determined by liquid scintillation. The estrone collected from the second chromatographic step was found to be at least 95% pure by methylation and rechromatography. Using the HPLC procedure, enzymatic ³H-estrone formation was found to be linear in a time and protein dependant manner.     

Determination of Some Penicillin Derivativies Using High Performance Liquid Chromatography

Abstract

A rapid, precise and selective method is described for determination of penicillin derivatives. Penicillin derivatives are separated from closely related degradation products by high performance liquid chromatography at ambient temperature using 10cm column packed with 5um Nucleosil RP₁₈ and buffered aqueous acetonitrile as mobile phase. The eluate is monitored at 254nm. The procedure is suitable for determination of 8 penicillin derivatives either in raw material or phamaceutical dosage forms.