Fig. 2.
Effect of ion-pairing reagent hydrophobicity on RP-HPLC behaviour of positively charged model peptides. Conditions: linear AB gradient (0.5% acetonitrile/min) at a flow-rate of 0.3 ml/min, where eluent A is 20 mM aq. H3PO4, TFA or PFPA and eluent B is 20 mM of the corresponding ion-pairing reagent in acetonitrile. The sequences of the peptides are shown in Table 1.