Sabadilla Alkaloids VI Separation of Veratridine and Cevadine by CountercurrentDistribution. pH vs. Partition Coefficients

Abstract

Contrary to previously reported results of partition studies, the plot of the partition coefficient vs. pH for both cevadine and veratridine has been shown to be linear. The two alkaloids were separated from each other in a high state of purity by countercurrent distribution with chloroform and 0.5 M citrate buffer at pH 3.95 with a relatively small number of transfers as well as on a partition column using the same conditions. A much greater number of transfers was required to separate them by countercurrent distribution with benzene and 0.5 M phosphate buffer at pH 5.85. No effective separation could be made on a partition column using the latter conditions. A nonaqueous titration for the alkaloids in benzene or chloroform solution was perfected and an ultraviolet spectral ratio method for detection and analysis of cevadine occurring with veratridine was applied.