Question

Suppose you are trying to separate a mixture of compounds using reversed-phase liquid chromatography (RPLC). On the first run, using a mobile phase containing 40% tetrahydrofuran and 60% water, the peaks all elute between 0 and 3 min and are too close together to be quantitatively resolved. To improve the resolution of the peaks, should you increase or decrease the amount of water in the mobile phase for the next run? Or is there not enough information?

In a separate experiment, you are trying to separate a mixture of compounds using normal-phase liquid chromatography (NPLC). On the first run, with a mobile phase containing 35% toluene and 65% acetonitrile, the peaks again eluted quickly and were poorly resolved. To improve the resolution of the peaks, should you increase or decrease the amount of acetonitrile in the mobile phase for the next run? Or is there not enough information?

Answer 1