What factors influence selectivity in liquid chromatography, and how can pH and ionic strength be used to adjust it?

What factors influence selectivity in liquid chromatography, and how can pH and ionic strength be used to adjust it?

• A. Only temperature.
• B. Detector type.
• C. Stationary phase chemistry, mobile phase composition (organic modifier), pH which controls ionization and interactions with silanol groups, and ionic strength which screens electrostatic interactions; adjusting pH and salt can tune retention and selectivity.
• D. Column length.

Answer: (C)