Chromatographic methods of separation

Enables coupling of SFE and various chromatographic methods of separation and detection... 

Chromatographic methods of separation are distinguished by their high selectivity, that is their ability to separate components of closely similar physical and chemical properties. Many mixtures which are difficult to separate by other methods may be separated by chromatography. The range of materials which can be processed covers the entire spectrum of molecular weights, from hydrogen to proteins. 

Dangwal SK. 1981. A quantitative paper chromatographic method of separation of nitrobenzene and p-nitrobenzene in air samples. American Industrial Hygiene Association Journal 42 557... 

Practical applications are again stressed in the Chapter by Lonngren and Svensson (Stockholm) on Mass Spectrometry in Stmctural Analysis of Natural Carbohydrates. They build on the fundamentals of carbohydrate mass spectrometry, as laid down by Kochetkov and Chizhov in Volume 21, and demonstrate the profound analytical value of mass spectrometry for structural analysis of complex polysaccharides. In particular, this tool has dramatically increased the scope of the traditional methylation linkage-analysis procedure, especially when used in conjunction with gas-liquid chromatographic methods of separation. The latter topic is the subject of complementary Chapters by Dutton, one already published in Volume 28 and the other scheduled for publication in Volume 30. 

Chromatographic methods of separation are of major importance for the analysis of toeopherols for two reasons (1) The most important quantitative method of determination, that of Emmerie and Engel (1938), and all other methods based on the reducing properties of the toeopherols, are unspecific. (2) The biological activity of the individual toeopherols differs considerably. Quantitative assay of toeopherols, therefore, requires that the extracts be purified beforehand in order to remove other reducing substances and that the mixture be separated into the individual toeopherols. 

In all chromatographic methods of separation and determination the differing distribution of the substance mixture to be separated between the fixed and liquid phases is important the use of different mobile phases also results in different separation efficiencies. Depending on the type of chromatographic technique used, the separated substances can be detected with the aid of various detectors. 

It is very interesting to find out that chromatographic method of separation of amino acid enantiomers was used for educational purposes [34]. Students realizing project of complete analysis of a biological active tetrapeptide, D-Ala-Gly-L-Phe-D-Leu (D- and L-amino acids ) carried out overnight hydrolysis, derivatization... 

---