Boronic acid is alkyl, or aryl substituted, boric acid. Boronic acid can form complexes with sugars, amines, and amino acids. Four aromatic boronic acids were separated on a Primesep P mixed-mode reversed-phase cation-exchange column. Primesep P column also has an aromatic fragment which provides pi-pi interaction. Compounds can be monitored by UV, ELSD, CAD and LC/MS. Various mobile phases can be employed for HPLC analysis of boronic acids.