High-performance liquid separation techniques

Tests carried out with the high performance liquid chromatographic technique endorsed the claim that it causes negligible degradation of both the chlorophylls and the xanthophylls. A more efficient separation of... 

Taylor and Nickless [1] have described a paired-ion high performance liquid chromatographic technique for the separation of mixtures of linear alkylbenzene sulphonates and p-sulphophenylcarboxylate salts,... 

J. H. Knox and G. R. Laird, Soap chromatography—a new high-performance liquid chromatographic technique for separation of ionizable materials Dyestuff intermediates,/. Chromatogr. 122 (1976), 17-34. 

High performance liquid chromatography Technique for separating chemicals in solution by passing an inert solvent over a sorbent. 

Separation of Polysaccharides Using High-Performance Liquid Chromatography Technique... 

Solid phase extraction (SPE) is a relatively new technique, which is similar in appearance and function to column chromatography and high-performance liquid chromatography (Techniques 19 and 21). In some applications, SPE is also similar to liquid-liquid extraction, discussed in this technique chapter. In addition to performing separation processes, SPE can also be used to carry out reactions in which new compounds are prepared. 

High performance liquid chromatography (HPLC) is an excellent technique for sample preseparation prior to GC injection since the separation efficiency is high, analysis time is short, and method development is easy. An LC-GC system could be fully automated and the selectivity characteristics of both the mobile and stationary... 

High performance liquid chromatography is an effective technique for the separation of compounds of high molecular weight. There are, however, two major problems with the use of mass spectrometry for the study of this type of molecule... 

High performance liquid chromatography (HPLC) has been by far the most important method for separating chlorophylls. Open column chromatography and thin layer chromatography are still used for clean-up procedures to isolate and separate carotenoids and other lipids from chlorophylls and for preparative applications, but both are losing importance for analytical purposes due to their low resolution and have been replaced by more effective techniques like solid phase, supercritical fluid extraction and counter current chromatography. The whole analysis should be as brief as possible, since each additional step is a potential source of epimers and allomers. 

The identification of the target colorant is done directly by UV-Vis spectrometry (if the colorant is unique) or by a previous separation from a mixture. The most available techniques are planar chromatography (paper chromatography and thin layer chromatography) and, especially, high performance liquid chromatography... 

The spectrum of new analytical techniques includes superior separation techniques and sophisticated detection methods. Most of the novel instruments are hyphenated, where the separation and detection elements are combined, allowing efficient use of materials sometimes available only in minute quantities. The hyphenated techniques also significantly increase the information content of the analysis. Recent developments in separation sciences are directed towards micro-analytical techniques, including capillary gas chromatography, microbore high performance liquid chromatography, and capillary electrophoresis. 

Capillary electrophoresis employing chiral selectors has been shown to be a useful analytical method to separate enantiomers. Conventionally, instrumental chiral separations have been achieved by gas chromatography and by high performance liquid chromatography.127 In recent years, there has been considerable activity in the separation and characterization of racemic pharmaceuticals by high performance capillary electrophoresis, with particular interest paid to using this technique in modem pharmaceutical analytical laboratories.128 130 The most frequently used chiral selectors in CE are cyclodextrins, crown ethers, chiral surfactants, bile acids, and protein-filled... 

Other kinds of bloassays have been used to detect the presence of specific allelochemical effects (8), effects on N2 fIxatlon (9), the presence of volatile compounds (10) and of Inhibitory substances produced by marine microalgae (11). Putnam and Duke (12) have summarized the extraction techniques and bioassay methods used In allelopathy research. Recent developments In high performance liquid chromatography (HPLC) separation of allelochemlcals from plant extracts dictates the need for bloassays with sensitivity to low concentrations of compounds contained In small volumes of eluent. Einhellig at al. (13) described a bloassay using Lemna minor L. growing In tissue culture cluster dish wells that maximizes sensitivity and minimizes sample requirements. 

MJ. Wilcox, Abstracts 22nd Inti Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 98), St Louis, MO (1998). 

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