Separation of nucleic acid component compounds on zwitterionic stationary phases

A method comprising:

• (a) loading a sample fluid comprising a plurality of nucleic acid component compounds onto a chromatographic column comprising a zwitterionic stationary phase contained inside the column, wherein the zwitterionic stationary phase is a particulate stationary phase and comprises (i) a bulk material comprising an ethylene bridged hybrid (BEH) material, and (ii) zwitterionic surface groups covalently linked to the bulk material or a zwitterionic polymer covalently linked to a surface of the bulk material;
• (b) flowing a mobile phase through the chromatographic column over a time period thereby forming an eluent in which at least some of the plurality of the nucleic acid component compounds are separated from each other, the mobile phase comprising a polar aprotic solvent, a protic solvent, and a volatile buffer salt, wherein flowing the mobile phase comprises varying a ratio of the protic solvent to the polar aprotic solvent over at least a portion of the time period and varying an ionic strength of the volatile buffer salt over at least a portion of the time period.