Micellar electrokinetic chromatography of ionic compounds: The analysis of hop bitter acids

Abstract

Successful separation of the six major hop bitter compounds by micellar electrokinetic chromatography depends critically on precise pH control. Any factor which can affect the actual in‐column pH must, therefore, also be carefully controlled: it has been found that temperature‐induced changes of the buffer pH can cause loss of resolution and even reversals in elution order. The pH level at which the effects occur suggests that the pKa values of the analytes are modified by the micellar medium.