Mechanism of selectivity in ion-pair high-performance liquid chromatography of aminoglycoside antibiotics using perfluorinated pairing ions.

The behaviour of perfluorinated carboxylic acids as pairing ions for the chromatography of the aminoglycoside antibiotics was studied. As with perhydrogenated pairing ions, the capacity factor can be modified according to the percentage of organic modifier and the nature and concentration of perfluorinated pairing ion in the mobile phase. The special selectivity effect observed with trifluoroacetic acid was investigated and interpreted as a concerted mechanism involving ionic and hydrophobic interactions.