Normal- and Reversed-Phase Behaviour of 16,17-Secoestrone Derivatives on Cyanopropyl-Bonded Silica Gel

The retention behaviour of a number of 16,17-secoestrone derivatives has been studied by LC and HPTLC on a polar cyanopropyl-bonded stationary phase using non-aqueous and aqueous-organic mobile phases. The retention behaviour has been discussed in terms of nature of the solute, eluent and stationary phase. The correlation between retention constants of 16,17-secoestrone derivatives obtained from reversed-phases and commercially available ACD log P software (Advanced Chemistry, Toronto, Canada) has also been examined.     

Separation of Aminoglycosides by Normal- and Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC - The normal-phase (NP) and reversed-phase (RP) thin-layer chromatographic separations of aminoglycosides (streptomycin, kanamycin,...     

Normal- and Reversed-Phase Thin-Layer Chromatography of Selected Calixarenes and Pyrene

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of calix[4]arene, 4-tert-butyl-calix[4]arene tribenzoate, 4-tert-butylcalix[5]arene, and pyrene have...     

Normal- and Reversed-Phase Thin-Layer Chromatography of Seven Oral Antidiabetic Agents

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of seven oral antidiabetic drugs -chlorpropamide, tolbutamide, glibenclamide, metformin, pioglitazone,...     

Chromatographic Retention Parameters of Certain Benzimidazole Derivatives on Octadecyl Silica Gel

Certain trends in chromatographic retention of benzimidazole derivatives on octadecyl silica gel (mobile phase phosphate buffer-acetonitrile) are considered. Retention parameters of compounds being separated are estimated and interpreted in terms of the reversed-phase HPLC theory.     

Chromatographic Analysis of New Antidepressant Drugs by Normal- and Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC - The selectivity of the TLC separation of six new antidepressant substances has been investigated on silanized silica gel C18 and on...     

Spectroscopic Study of Cerium-Doped Silica Gel Monoliths and Their Densified Derivatives

Cerium is exploited as a probe cation for elucidating the structure of an alkoxide-derived silica gel and its progressive evolution to a glass network as a function of heat-treatment up to 1000°C. At intermediate temperatures, the host structure exhibits inhomogeneity due to insufficient formation of siloxane bonds, which is reflected by at least two different sites and co-ordination spheres (termed “high” and “low” water ligation) for cerium. This is proved by the response of the gels heated up to 700°C to rehydration. Further formation of Si−O−Si network (900°C) leads to the destruction of the “high water” sites of cerium and progression towards a glassy structure. It is, however, only after heat-treatment at 1000°C that a dense silica glass network, not responding to rehydration, is finally obtained with cerium ions embedded in it.     

有机试剂键合硅胶对牛血清白蛋白的吸附行为

介绍几种偶氮，卟啉，三苯甲烷类有机试剂键合硅胶的合成方法，研究其吸附牛血清白蛋白（ＢＳＡ）的行为，研究结果表明：ＴＰＰ．ＳＧ吸附性能最佳，对ＢＳＡ吸附平衡１ｈ即可达到，最大吸附率为９０％，最大吸附容量为１２．２ｍｇ／ｇ。     

卟啉试剂键合硅胶对蛋白质吸附行为的研究

报道了几种卟啉试剂键合硅胶的合成并研究了它们对蛋白质的吸附行为。结果表明 meso-四苯基卟啉键合硅胶 ( TPP· SG)对人血清白蛋白 ( HSA)的最大吸附容量为 1 3.4mg/g,最大吸附率达 92 % ,吸附平衡时间为 60 mi     

The Behaviour of Some Benzene Derivatives on Thin Layers of Aluminum Oxide—Comparation with Plain and Fe(III)Impregnated Silica Gel

Abstract

The behaviour of some carboxy and hydroxy benzene derivatives related to humic material was examined by thin layer chromatography on aluminium oxide as the support and water as developer. Their Rf-values were compared with those on plain and Fe(III)-impregnated silica gel plates.     

硅胶及其衍生物作为基体的激光解吸离子化飞行时间质谱

制备了一种新型无机基体材料(硅胶及其衍生物)用于测定激光解吸离子化飞行时间质谱,建立了一种新的质谱分析方法,并用以解决传统MALDI-TOFMS存在的基体干扰问题.该法适合于低分子量化合物的分析.同时探讨了该新解吸离子化方法的机理.     

呋喃类化合物在离子液体和硅胶负载离子液体中的Diels-Alder反应

以1-丁基-3-甲基咪唑盐作为离子液体阳离子,与3种不同阴离子BF4、PF6、Tf2N组成性质不同的3种离子液体,催化呋喃类和丁炔二羧酸酯之间发生Diels-Alder反应,合成了一系列化合物,研究了离子液体的催化效果.研究结果表明,呋喃类化合物的极性越低, Diels-Alder反应的活性越高.在含硫的呋喃类化合物的反应中,当以[Bmim]PF6作离子液体时,Diels-Alder反应产率可达53%.当[Bmim]PF6离子液体被吸附在硅胶表面上时,Diels-Alder的反应产率有所提高.     

Normal- and Reversed-Phase Thin-Layer Chromatography of Three Structurally Related Organophosphorus Pesticides of Forensic Importance

JPC – Journal of Planar Chromatography – Modern TLC - Recently, considerable numbers of poisoning cases have been reported owing to the ingestion of three structurally related...     

New 3-Aminopropylsilatrane Derivatives and Sorption Activity of the Silica Gel Modified by Them

Russian Journal of General Chemistry - New functionalized silatranes were synthesized by the reaction of 3-aminopropylsilatrane with urea, thiourea, guanidine, acetamide, acetylguanidine, and...     

Liquid Chromatographic Analysis of a New Antihypertensive Agent,PD 78,799, in Plasma on Silica Gel with Reversed-Phase Eluent

Abstract

A sensitive and selective HPLC assay has been developed for the analysis of a new antihypertensive agent in human plasma. The drug and internal standard were isolated from plasma by liquid-liquid extraction. Separation was accomplished on unmodified silica gel with a mobile phase of 60:40 acetonitrile:10 mM dibasic ammonium phosphate. Detection was by UV absorbance at 291 nm. The method is linear over a range of 20 to 4000 ng/ml. Relative error of calibration and control standards ranged from ?1.5 to 5.0% and precision, as indicated by relative standard deviation, ranged from 0.8 to 5.2%. The method has been successfully used for analysis of plasma samples from human volunteers following oral administration of PD 78,799.     

阴、阳离子表面活性剂混合体系在硅胶/水及硅胶/矿化水界面上的吸附

研究阴、阳离子表面活性剂混合体系(十二烷基氯代吡啶,辛基磺酸钠,辛基三乙基溴化铵/十二烷基苯磺酸钠)在硅胶,纯水和硅胶,矿化水界面上的吸附作用,探讨阴(阳)离子表面活性剂的存在对阳(阴)离子表面活性剂吸附作用的影响．结果表明,阴离子表面活性剂的存在基本不影响阳离子表面活性剂在带负电固体表面的吸附;而阳离子表面活性剂的存在却使本来吸附量就不大的阴离子表面活性剂在带负电的固体表面上不再吸附．在矿化水中阳离子表面活性剂的吸附量比在纯水中明显降低．从硅胶表面吸附机制解释了所得结果．     

Normal- and Reversed-Phase Thin-Layer Chromatography of Amino Acids on Unconventional Supports with Mixed Mobile Phases Containing Dimethyl Sulfoxide

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of twenty-four amino acids has been studied on untreated and on triaryl phosphate (TAP)-impregnated...     

Correlation of Retention Data of Pesticides in Normal- and Reversed-Phase Systems and Utilization of the Data for Separation of a Mixture of Ten Urea Herbicides by Two-Dimensional Thin-Layer Chromatography on Cyanopropyl-Bonded Polar Stationary Phase and on a Two-Adsorbent-Layer Multi-K SC5 Plate

JPC – Journal of Planar Chromatography – Modern TLC - The selectivities of TLC systems have been compared by use of correlations between RF(II) and RF(I) values (by analogy with...     

Chiral Separation of Carboxymethyl Derivatives of Amines by Liquid Chromatography on Reversed-phase Silica Gel Coated with N-n-Dodecyl-L-hydroxyproline

Carboxymethyl derivatives of amines containing a chiral α-carbon were separated into enantiomers by high-performance liquid chromatography using octadecylsilanized silica gel coated with N-n-dodecyl-L-hydroxyproline as the stationary phase and an aqueous solution containing copper(II) as the mobile phase. Detection was by post-column reaction involving derivatization to tertiary amine and chemiluminescence reaction of ruthenium bipyridine complex.     

Polymer-Modified Silica Adsorbent with Reversed-Phase and Weak Cation-Exchange Groups

Micro-spherical silica gel has been modified with a polymer containing two different functional groups (C₁₈ and COOH) by use of a copolymer of octadecyl methacrylate and butyl acrylate and introduction of maleic anhydride. The chromatographic properties of these stationary phases in reversed-phase high-performance liquid chromatography (HPLC) have been studied over a broad pH range. Introduction of maleic anhydride as the third component of the polymer layer on the surface of micro-spherical silica leads to repartitioning of C₁₈ groups, which affects the hydrophobicity of the materials obtained. The presence of maleic anhydride secures the availability of carboxyl groups on the surface, and thus the acidic properties of the material.