(a) When you try separating an unknown mixture by reversedphase chromatography with 50 % acetonitrile/50% water, the peaks are too close together and are eluted in the range k=2-6. Should you use a higher or lower concentration of acetonitrile in the next run? (b) When you try separating an unknown mixture by normal-phase chromatography with pure 50 % hexane/50% methyl t-butyl ether, the peaks are too close together and are eluted in the range k=2-6. Should you use a higher or lower concentratio

(a) Why does eluent strength increase as solvent becomes less polar in reversed-phase chromatography, whereas eluent strength increases as solvent becomes more polar in normal-phase chromatography? (b) What kind of gradient is used in supercritical fluid chromatography? | Numerade

SOLVED: Select a strategy that will specifically increase the retention time of polar/acidic amino acids (e.g., glutamic acid) when using reversed-phase liquid chromatography:1. Addition of triethylamine as an ion pair reagent to the mobile phase2. Increase the column diameter3. Optimize the flow rate of the mobile phase4. Decrease the particle diameter5. Increase the organic content of the mobile phase

HPLC - Normal Phase vs Reverse Phase HPLC - Animated on Make a GIF

HPLC - Normal Phase vs Reverse Phase HPLC - Animated on Make a GIF

What is the difference between normal-phase and reverse-phase HPLC? | Numerade

Ion pair chromatography in reverse phase HPLC

Ion Pair Chromatography – How IPC Works, Strengths, Limitations and Applications