The activity (acidity) of residual silanol groups on the surface of silica gel, metal residues in silica gel, and unevenness on the surface of silica gel are important factors leading to asymmetric chromatographic peaks, tailing, and poor reproducibility of polar compounds. The innovative silicone double-layer surface treatment technology of Bonaijer Technology can effectively overcome the influence of the factors that lead to poor separation of polar compounds mentioned above.

Bonaijer Technology has launched a system solution for HPLC separation of strongly polar compounds based on silica gel double-layer surface treatment technology: Venusil MP C18, Venusil ASB C18 *, and Venusil HILIC series chromatography columns, making the separation of strongly polar compounds no longer a difficult problem, and you will have an unprecedented chromatographic experience.

The principle of double-layer surface treatment technology for silicone is shown in Figure 1. Silicone A is first surface bonded with orthosilicate B to obtain C, which is further hydrolyzed into D. Compared to the initial silicone A, D adds a new layer of surface (the dashed box of D in Figure 1).

The newly added surface layer has the following advantages compared to the initial surface layer of silicone A:

1. The acidity of the silicon hydroxyl groups in the new surface layer is greatly reduced (pH=5.2 for newly added silicon hydroxyl groups and pH=3.5 for ordinary silica gel hydroxyl groups), and the activity of silicon hydroxyl groups is reduced, resulting in secondary retention of alkaline compounds

The effect is greatly weakened, and the peak shape of alkaline compounds is sharper and more symmetrical.

2. The new surface layer covers the metal residues in the initial silica gel, increases the purity of the silica gel surface, shields the adverse effects of residual metals on polar compounds, and greatly improves the peak shape.

3. The new surface layer covers the surface unevenness caused by the formation of silica gel microcrystals, making the silica gel surface more uniform and reproducible.

4. The new surface layer has more silicon hydroxyl groups, increased hydrophilicity, and can use 100% water or buffer salts as the mobile phase, greatly increasing the flexibility of method development.

Figure 1 Schematic diagram of double-layer surface treatment of silicone

Figure 2 Schematic diagram of Venusil ASB C18 silicone surface bonding technology

Note: Venusil ASB C18 is formed by bonding isobutyl silane onto a new surface layer of silica gel.