Thin-layer chromatography of pteroylmonoglutamates and related compounds.

TLDR: This chapter discusses thin-layer chromatography (TLC) of pteroylmonoglutamates and related compounds, and a single solvent system gives good separation of most of the more important derivatives.

Abstract: Publisher Summary This chapter discusses thin-layer chromatography (TLC) of pteroylmonoglutamates and related compounds. The naturally occurring pteroylmonoglutamates can be separated from each other and identified by TLC. A single solvent system— namely, 3.0% (w/v) NH 4 Cl— gives good separation of most of the more important derivatives. The separated folates can be detected on the TLC plates, either by their fluorescent properties or, if they are present in trace amounts, by the removal of the powder in sections from the plates followed by desorption and microbiological assay, using Lactobacillus casei . This technique is not suitable for the separation of folate polyglutamates, and where these forms exist, they must be converted to the corresponding folate monoglutamate by enzymic hydrolysis prior to their separation. The pteroylmonoglutamate standards containing 0.5% MET are applied in the minimum possible volume so that approximately 5 μg of each derivative are applied. Biological extracts are also applied in minimum volume to achieve a concentration greater than 50 μg of folate activity per sample. Where the levels of folates are low, thicker plates may be used and more sample applied or the sample may be lyophilized and resuspended prior to the application. The plates are developed in different solvents at room temperature, usually for 80-90 min.