Figure 3: The effect of varying the buffer pHs to (a) 2.0 (b) 2.8 (c) 4.0 (d) 6.0 (e) 2.3 (four compounds), the mobile phase used was 25:75 MeOH:Heptanesulfonic sodium salt (0.05 mM) with 0.1% TEA, running at 0.5 ml/min; (e) 2.3, the mobile phase used was 35:65 MeOH:Heptanesulfonic sodium salt (0.05 mM) with 0.05% TEA, running at 0.5 ml/min. The detection was done at 210 nm