Paper chromatography Phenolic plant extracts

In earlier times, thin-layer chromatography (TLC), polyamide chromatography, and paper electrophoresis were the major separation techniques for phenolics. Of these methods, TLC is still the workhorse of flavonoid analysis. It is used as a rapid, simple, and versatile method for following polyphenolics in plant extracts and in fractionation work. However, the majority of published work now refers to qualitative and quantitative applications of high-performance liquid chromatography (HPLC) for analysis. Llavonoids can be separated. 

Guenzi and McCalla (1966) extracted soils with various extractants, and by paper chromatography identified several phenolic acids. The concentrations were probably too low to produce appreciable effects on plant growth if we assume even distribution throughout the soil. Much higher concentrations of the phytotoxins would be expected in the immediate vicinity of decaying crop residues. 

Types of thin layers. The phenolic acids arising from clinical studies (88) have been examined by TLC on cellulose (88-90) and with cellulose on Silufol (91). TLC was considered superior to paper chromatography. The identification of phenolic acids in varieties of Ribes nigrum has been described (IS), and separation of phenolic acids fix>m plant material or silica gel G and quantitative analysis with spectrophotometry (92). Phenolic acids extracted from plants were best separated on silica gel G with chloroform-ethyl acetate-formic acid (5 4 1) (8). TLC on silica gel combined with scanning spectrophotometry was used to separate nine phenolic acids in wine with hexane-ethyl acetate-formic acid (15 9 2) (93) as the preferred of the 10 solvents examined. Twenty naturally occurring phenolic acids were separated by a combination of one- and two-dimensional TLC and development with three solvents (94) and phenolic acids (and some phenols) related to humic acid examined on alumina with water as solvent (94a). Silica gel F-254 (Silica-Rapid-Platten Woelm in... 

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