Technical Problems with the Application of Solutes to Chromatographic Plates in TLC

JPC – Journal of Planar Chromatography – Modern TLC - This paper describes the effect of the method of application of samples to chromatographic plates on the RF values and resolution...     

Synthesis of C3-Modified Carbapenems

Russian Journal of Organic Chemistry - Reactions of 4-nitrobenzyl (4R,5R,6S)-3-[(diphenoxyphosphoryl)oxy]-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate with...     

New Reagent for Detection of Amino Acids on TLC Plates

JPC – Journal of Planar Chromatography – Modern TLC -     

Mechanistic Study of Microwave-Assisted Acid Hydrolysis of Peptides on TLC Plates

Abstract

Microwave-induced acid hydrolysis was performed with isolated peptides on TLC layers. This vapor phase method was compared to solution phase techniques. A mechanistic study of peptide bond clevage was carried out by varying exposure conditions and reaction time. Acid hydrolysis products were identified by ninhydrin visualization. Also, TLC and TLC/MS were used to elucidate hydrolysis mechanisms.     

中孔分子筛SBA-15作为液相色谱固定相以及在巯基化合物分离中的应用

采用共表面活性剂法合成了孔道结构高度有序、孔径较大且粒径均匀的SBA－15颗粒，并在此基础上研究了其作为毛细管液相色谱柱的填料基体的特性。在SBA－15材料上进行C18官能团化前后，分别对4种巯基化合物即半胱氨酸、谷胱甘肽、多巴胺和6－巯基嘌呤进行了分离分析。     

Color and Chemical Reactions of Selected Sesquiterpene Lactones and Ecdysones from Asteraceae on TLC Plates

JPC – Journal of Planar Chromatography – Modern TLC -     

Aqueous Urea Solution Promoted Resolution of Five-Component Mixture of Amino Acids on Silica TLC Plates

JPC – Journal of Planar Chromatography – Modern TLC - A thin-layer chromatographic system comprising of silica gel as stationary phase and 1.0% aqueous urea solution as mobile phase (pH...     

Fluorescence Screening of Organophosphorus Pesticides in Water by an Enzyme Inhibition Procedure on TLC Plates

JPC – Journal of Planar Chromatography – Modern TLC - An enzymatic inhibition method sufficiently sensitive for rapid screening of seven organophosphorus pesticides in water is...     

薄层色谱展开方法的几处改进

介绍了几种薄层色谱展开方法，包括中途展开、接力展开、多维接力展开、改进二维展开等，还介绍了一种简单的下行展开的操作方式以及关键部件的制作方法。     

Ligand Exchange Reactions for the Fluorescent Detection of Nanogram Amounts of Metal Ions on TLC Plates

Abstract

A number of metal ions have been separated as their diethyldithiocarbamate chelates by thin-layer chromatography and detected by means of a ligand exchange reaction between a metal/calcein complex and the diethyldithiocarbamate chelate. Visual detection limits, after development, are 0.1 to 2 ng per spot for the metal ions studied. The potential of this new method for the fluorescent analysis of metal ions is discussed. It is particularly promising as a simple field method. Spiked natural water samples are analyzed to demonstrate its usefulness.     

The Application of Topological Indexes in TLC

JPC – Journal of Planar Chromatography – Modern TLC - This review covers the use of topological indexes based on the adjacency and distance matrixes to predict the RF and RM values, and...     

Porous Organic Cage-Embedded C10-Modified Silica as HPLC Stationary Phase and Its Multiple Separation Functions

Reduced imine cage (RCC3) was covalently bonded to the surface of silica spheres, and then the secondary amine group of the molecular cage was embedded in non-polar C10 for modification to prepare a novel RCC3-C10@silica HPLC stationary phase with multiple separation functions. Through infrared spectroscopy, thermogravimetric analysis and nitrogen adsorption–desorption characterization, it was confirmed that RCC3-C10 was successfully bonded to the surface of silica spheres. The resolution of RCC3-C10@silica in reversed-phase separation mode is as high as 2.95, 3.73, 3.27 and 4.09 for p-phenethyl alcohol, 1-phenyl-2-propanol, p-methylphenethyl alcohol and 1-phenyl-1-propanol, indicating that the stationary phase has excellent chiral resolution performance. In reversed-phase and hydrophilic separation modes, RCC3-C10@silica realized the separation and analysis of a total of 70 compounds in 8 classes of Tanaka mixtures, alkylbenzene rings, polyphenyl rings, phenols, anilines, sulfonamides, nucleosides and flavonoids, and the analysis of a variety of chiral and achiral complex mixtures have been completed at the same time. Compared with the traditional C18 commercial column, RCC3-C10@silica exhibits better chromatographic separation selectivity, aromatic selectivity and polar selectivity. The multifunctional separation mechanism exhibited by the stationary phase originates from various synergistic effects such as hydrophobic interaction, π-π interaction, hydrogen bonding and steric interaction provided by RCC3 and C10 groups. This work provides flexible selectivity and application prospects for novel multi-separation functional chromatographic columns.     

LC Separation of Co-Existing Cetylpyridinium Chloride, Tetradecyltrimethylammonium Bromide and Dodecyltrimethylammonium Bromide on Silica TLC Plates with Aqueous-Organic Eluents

Thin-layer chromatography (TLC) of three cationic surfactants was performed on silica TLC plates with various solvent systems. The mutual separation of cetylpyridinium chloride (CPC), tetradecyltrimethylammonium bromide (TTAB) and dodecyltrimethylammonium bromide (DTAB) was achieved on silica TLC plates with ethanol: 1% aqueous ammonium chloride (4:6, v/v) as an eluent. Effects of cations and anions in the mobile phase on mobility and separation of CPC, TTAB and DTAB were examined. The interference due to the presence of metal cations as impurities on the resolution in the mixture of CPC, TTAB and DTAB was also examined. The limits of detection of CPC, TTAB and DTAB estimated were 0.015, 0.031 and 0.062 μg zone⁻¹, respectively. The developed method was utilized to identify these surfactants in different spiked water samples after their preliminary separation.     

Application of a Mixed Adsorbent for Flow TLC

JPC – Journal of Planar Chromatography – Modern TLC -     

Comparison of Mobile Phases for Separation of Phospholipids by One-Dimensional TLC on Preadsorbent High Performance Silica Gel Plates

Abstract

Eight solvent systems reported in the literature for the one-dimensional TLC separation of phospholipids were compared under identical conditions using high performance preadsorbent silica gel plates. The best overall separation of phospholipid standards was obtained by a single development with chloroform-methanol-water (65:25:4), and three other systems containing chloroform also gave good separations. Rf data are tabulated for these four systems, and the phospholipids extracted from the digestive gland-gonad complex of Biomphalaria glabrata snails are identified.     

Development and Validation of TLC Method for Analysis of Stresroak Premix

JPC – Journal of Planar Chromatography – Modern TLC - With the realization of the growing popularity and demand for phytopharmaceuticals, standardization is becoming a mandatory part of...     

Comparison of Mobile Phases for Separation and Quantification of Lipids by One-Dimensional TLC on Preadsorbent High Performance Silica Gel Plates

Abstract

Twenty-four solvent systems reported in the literature for the one-dimensional TLC separation of lipids and phospholipids were compared under identical conditions using high performance preadsorbent silica gel plates. The best overall separation of mixtures of neutral lipid and phospholipid standards and compounds extracted from the digestive gland-gonad complex of Biomphalaria glabrata snails was obtained with a system utilizing consecutive development with chloroform-methanol-water (65:25:4), chloroform-hexane (3:1), and carbon tetrachloride. The best system for quantification of neutral lipids was hexane-diethyl ether-formic acid (80:20:2). R_f data are tabulated and results discussed for all systems tested.     

Application of mesoporous SiO2-Modified carbon paste electrode for voltammetric determination of epinephrine

Mesoporous SiO₂ of SBA-15 is reported to modify carbon paste electrodes for detecting epinephrine (EP). Carbon paste electrodes modified with synthesized SBA-15 show high sensitivity for voltammetric determination of EP, which is attributed to the strong adsorption ability of SBA-15 to EP and large surface area of the working electrode resulted from SBA-15 modification. The effects of pH value, amount of SBA-15 and scan rate were investigated. Under optimum conditions, the anodic peak current of EP was proportional to its concentration over the range from 1.0 × 10^?6 to 6.0 × 10^?5 mol L^?1 and the limit of detection was 6.0 × 10^?7 mol L^?1. The results show mesoporous SiO₂-modified carbon paste electrodes, particularly SBA-15-modificd electrodes, create new opportunities for sensitive, simple and suitable method in the electrochemical analysis of EP.     

PID—100C型光离子化气相色谱仪的研制与应用

作者研制一种微机化光离子化气相色谱仪，其灵敏度和检出限优于ＦＩＤ两个数量级（苯）可用于有机挥发物痕量分析。     

A new and highly sensitive TLC method to measure hypericin using chemiluminescence

ABSTRACT

Hypericin is a polyphenolic compound belonging to the group of polyphenols and is the active constituents of Hypericum perforatum (Saint John’s wort). We present a new high-performance thin-layer chromatography (HPTLC) method to measure a large number of hypericin extracts using chemiluminescence. On a 10?×?10?cm HPTLC plate (LiChrospher® Merck, 1.05586), more than 40 tracks can be simultaneously quantified using a piezoelectric application system (pipeJet) which can apply 56?nL of a methanolic hypericin extract contactless with high precision. For separation, a solvent mixture of ethyl acetate, water, formic acid, methyl tert-butyl ether, and cyclohexane (180?+?14?+?14?+?80?+?30, v/v) was used. The R_f-value of hypericin is 0.27. The method presented is specific for hypericin and offers a limit of quantification of 690 pg hypericin per band.