Liquid chromatography-nuclear magnetic substances separation

In order to investigate the properties of individual fractions of humic substances, various modes of high performance liquid chromatography (HPLC) have been employed. Hydrophobic interaction chromatography (5) has proved to be an effective separation technique, resulting in five distinct humic fractions from one sample. Structural analysis of these fractions was subsequently performed by infrared and nuclear magnetic resonance spectroscopy, and molecular weight distribution was also measured. 

TLC is useful both as an analytical and a preparative technique, and substances tentatively identified by TLC may be further characterized by various analytical techniques such as nuclear magnetic resonance spectrometry, mass spectrometry, or gas liquid chromatography. Moreover, many specific chemical detection tests are available to help identify substances separated by TLC. TLC is a microanalytical procedure and provides for separations and at least tentative identification of substances in the milligram (mg), microgram (/ig), and nanogram (ng) range. TLC can provide the biochemist with a method of eluting separated substances from plates for quantitative analyses. Recent studies indicate that elution techniques may not be the best alternative for quantitative analyses of many substances separated by TLC and that the preferred method may involve quantitative in situ densitometric analysis [1,2]. 

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