ERGOT ALKALOIDS AS CHIRAL SELECTORS IN CAPILLARY ELECTROPHORESIS - DETERMINATION OF THE SEPARATION MECHANISM

Recently ergot alkaloids were introduced as novel chiral selectors in capillary electrophoresis. In the present study, stereoselectivities o f several ergot alkaloids, added to the background electrolyte (BGE), towards some racemic hydroxy organic acids are compared. The 1-allyl d erivative of (5R,8S,10R)-terguride (allyl-TER) proved to be the best c hiral selector for these analytes. Only the capillary was filled with BGE containing the chiral selector. The in- and outlet vial did not al kaloid. The effects of pH, and MeOH added to the BGE were investigated . Low pH proved to have an adverse effect on enantioseparation. Good s eparation for the enantiomers of some a-hydroxy acids was obtained at pH 4.2, and 25 mM allyl-TER. The addition of 50% MeOH to the BGE alter ed stereoselectivity and increased the solubility of the chiral select or. Using a BGE containing 50% MeOH, and 62.5 mM allyl-TER at pH 5.5, the optical isomers of all test compounds, including tropic acid and other organic acids, were baseline resolved.