ODS-A and AM are conventional ODS. ODS-AQ provides a lower rate of carbon content and is suitable for separation of hydrophilic compounds. ODS-A and -AM have the same basic physical properties such as the base material, the rate of carbon content and the separation characteristics, however -AM is produced under more strict Standards of Quality Control.

Polyamine II and PA-G are chemically bonded with polyamine where NH₂ is with aminopropyl group. Polyamine II and PA-G are superior to NH₂ in durability. They also have difference in selectivity. Polyamine II and PA-G have different ligand structure of polyamine. Polyamine II is superior to PA-G in durability.

General ODS (C18) packing material is a silica gel bonded with octadecyl groups. This is in the result of a reaction between silanol groups and octadecyl groups on the silica surface. However some silanol groups remain after the reaction. It is impossible for all the silanol groups to react because of steric hindrance of octadecyl groups. Such residual silanol groups create a secondary interaction in chromatography, which, in many cases, affects on chromatograms by, in general, causing a peak tailing of basic compounds or irreversible absorption to the column. Therefore, a secondary silanization on residual silanol groups with unbulky silanization reagents should be performed. This process is called “endcapping”. Trimethylsilane (TMS) is commonly used in “endcapping” process.

“Triart C18”, “Hydrosphere C18” and “ODS-AQ” columns can be used with 100% aqueous mobile phase. On conventional ODS columns, retention time is shortened due to the incompatibility between water and material surface with high hydrophobicity. Water tends to be expelled from the pores on material. The retention time hardly shortened on “YMC-Triart C18”, “Hydrosphere C18” and “ODS-AQ” because they are capable of solvation between mobile phase and hydrophilic surface by reducing the density of C18 functional groups.

• YMC-Triart C18
• Hydrosphere C18
• YMC-Pack ODS-AQ