RP-HPLC Separation of Highly Charged Quaternary Ammonium Salts

Abstract
The reverse phase HPLC separation of polycationic viologenes 1 – 4 and macrotricyclic quaternary ammonium salts 5 – 8 using ion pair conditions is described. Whereas the compounds 1 – 4 could be analysed on any of 4 stationary RP-18 phases tested, the cage compounds 5 – 8 were much more sensitive to the source of the matrix material. Optimal separation conditions for the latter up to eightfold positively charged macrocycles employ sodium perchlorate in acidic aqueous methanol using Nucleosil RP-18 or Lichrospher CH-18 columns.