Electrophoretic Movement of Higher Fatty Acids on Filter Paper

Abstract

ATTEMPTS at the separation of higher fatty acids by paper chromatography have not, in the main, been successful, although Isherwood and Hanes¹ have studied the problem in relation to a number of straight-chain fatty acids, and Nunez and Spiten² have evolved a technique, using paper impregnated with olive oil, for chromatographic separation of such compounds. Apart from other considerations, the low aqueous solubility and the low dissociation constants of these acids presented the problem of finding an indicator which would be sensitive enough to enable their presence to be detected on paper. It has been found that the methyl red/bromthymol blue indicator of Duncan and Porteous³ permits of the detection of small amounts (for example, about 80 µgm. of C₁₆) of acids up to C₁₈ on paper. Considerably more care is required, however, in the colour development with the higher acids than with the lower members of the series.