摘要:

Mobile phase optimization is highly important in planar chromatography. Solvent selection based on experience and chromatographic intuition can be very time consuming when applied to complex mixtures. In these cases, more systematic strategies are needed. This paper presents a new mathematical model for the optimization of the mobile phase composition used for the separation of a mixture of 1,4-benzodiazepines and a comparison of this mathematical approach with other models.

ISSN:1082-6076    

DOI:10.1081/JLC-100101742

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The HPTLC behavior of closely related N-phenylamide derivatives of phenoxyacetic acid has been studied on silica gel and diol-modified silica gel layers developed with binary non-aqueous mobile phases (ethyl acetate, dioxane, or methyl ethyl ketone in n-heptane or dichloromethane). The influence of the different polar modifiers on the retention was illustrated as linear plots of RM= f(log c). The separation selectivities of the investigated compounds on silica gel and diol phases were compared as RM(silica)vs. RM(diol)relationships.

ISSN:1082-6076    

DOI:10.1081/JLC-100101743

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In this paper, thin-layer chromatography and high-performance liquid chromatography for the qualitative and quantitative analysis of phenolic acids inGinkgo bilobaL. leaves are described. The amounts of both free and bound phenolic acids were determined within the whole vegetative period. For this purpose, a special extraction procedure, comprising acid and alkaline hydrolyses, was used. The described method allowed us to identify and estimate the concentration levels of eight phenolic acids: protocatechuic,para-hydroxybenzoic, vanillic, caffeic, isovanillic,para-coumaric, ferulic, and sinapic.

ISSN:1082-6076    

DOI:10.1081/JLC-100101744

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The chromatographic behavior of 31 samples of variously substituted 2,5-anhydroaldohexose ethylene acetal derivatives has been studied on silica gel and C-18 modified silica gel layers with, respectively, binary non-aqueous and aqueous mobile phases. The slopes and intercepts of the linear relationships between the retention constant (RM) and the logarithm of the volume fraction of the diluent in non-aqueous mobile phase, as well as of the volume fraction of organic component in aqueous-organic mobile phase, have been calculated and are discussed in relation to solute and mobile and stationary phase characteristics. The retention and relative retention of compounds depend largely on the retention behavior of their substituents.

ISSN:1082-6076    

DOI:10.1081/JLC-100101745

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Second messenger ceramides differ in their composition according to the nature of their sphingoid bases and their amide linked fatty acids. These different species may be involved in many different biological responses, as may be the diacylglycerol species. For this reason, it is interesting to have a simple method which allows for the separation of these compounds into classes of species for further analysis.

ISSN:1082-6076    

DOI:10.1081/JLC-100101746

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A method for the determination of solasodine glycosides using western blotting was investigated. Solasodine glycosides, separated by silica gel thin-layer chromatography, were transferred to a polyvinylidene difluoride membrane. The membrane was treated with sodium periodate solution followed by bovine serum albumin, resulting in a solasodine glycoside-bovine serum albumin conjugate. Individual spots were stained with monoclonal antibody against solamargine. Immunostaining of solasodine glycosides was more sensitive compared with other staining methods. The newly established western blotting method is extended to the distribution of solasodine glycosides in plants.

ISSN:1082-6076    

DOI:10.1081/JLC-100101747

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The efficiency of silver ion and reversed-phase thin layer chromatography in the analysis of triacylglycerols is discussed in this paper. The experimental conditions that allowed for the conversion of these techniques into full-scale quantitative analytical methods are presented and details of the respective protocols are given. Examples are presented that demonstrate the achievements of thin-layer chromatography in elucidating the triacylglycerol structure of natural and modified lipid samples.

ISSN:1082-6076    

DOI:10.1081/JLC-100101748

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

High performance thin-layer chromatography analysis was used to analyze neutral lipids in the digestive gland-gonad (DGG) complex of the marine snailsIlyanassa obsoletusandLittorina littoreainfected with larval trematodes. The results were compared with the DGGs of snails not infected with larval trematodes. The most abundant neutral lipid in both infected and non-infected snails was triacylglycerols, with percentages ranging from 2.8% inI. obsoletussnails infected with unidentified armatae cercariae to 24.7% inI. obsoletussnails infected withZoogonius rubellus.L. littoreasnails infected with an unidentified armatae cercaria contained 6 to 7 times the amount of cholesteryl ester than uninfected snails or those infected withCryptocotyle linguacercariae.I. obsoletussnails infected withZ. rubellusor an unidentified armatae cercaria contained 2 to 3 times more free sterol than the uninfected controls. Larval trematode parasitism was found to alter the neutral lipid profiles of the marine snailsI. obsoletusandL. littorea.

ISSN:1082-6076    

DOI:10.1081/JLC-100101749

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Several accidents were reported in France, in domestic and wild animals, involving the potential ingestion of imidacloprid-coated seeds. Imidacloprid is a new insecticide which acts as a nicotinic blocker. Since there was very limited published information regarding this compound, its toxicity to wild birds, and potential routine analytical techniques, this study was designed to set up and validate a method for the detection and quantification of imidacloprid and its primary metabolite, 6-chloronicotinic acid, in tissues and organs of affected animals. A high performance thin layer chromatography (HPTLC) technique was developed to quantify both compounds. The method is repeatable, reproducible, and sensitive enough to investigate potential poisoning cases (limits of quantification between 0.25 and 0.5 μg/g).

ISSN:1082-6076    

DOI:10.1081/JLC-100101750

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A rapid and simple high performance thin layer chromatographic method has been developed for the simultaneous quantitation of pharmacologically important diaryl heptanoids curcumin, demethoxy curcumin, and bis-demethoxy curcumin inCurcuma longaandC. amada.The assay combines the isolation and separation of curcuminoids on silica gel 60F254high performance thin layer chromatographic plates, followed by scanning of the spots at 366 nm using a UV detection mode.

ISSN:1082-6076    

DOI:10.1081/JLC-100101751

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor