“…The treatment of the solid support with alkali as a method of suppressing acid sites proved very fruitful in separating alkaloids. 16 " 21 The investigation of the Chromatographie behavior of HC (pyridine, furan, thiophene derivatives) on columns packed with the alkali-treated solid support revealed that alkali markedly reduced the solid support specific area, decreased discernibly retention times and effectively eliminated tailing effects in the case of pyridine bases; moreover, alkali participated in the separation process bringing about specific interactions. [22][23][24][25][26][27] In studying the separation of amines and nitrogen-containing HC (pyridine, piperidine, pyrrolidine, pyrrole, picolines), Golovnya et al likewise faced a problem of the specific influence of alkali on the liquid phase properties (polarity increase).…”