There are many HPLC columns worldwide that are manufactured using hybrid particles. Hybrid particles are a packing material consisting of silica (inorganic) cross-linked with polymers (organic) such as ethylene and are sometimes referred to as organosilica.
The primary advantage of hybrid particles is their high alkali resistance. However, the durability performance differs significantly between partially hybrid silica particles, where only the silica surface is modified, and fully hybrid silica particles, where the entire structure is composed of organosilica.

For example, Prominert, a concept column for general-purpose HPLC that we developed in 2022, features 3.5 μm high-efficiency silica particles with excellent durability. However, as shown in the figure below, the Tandem TMS end-capping process is applied to the surface of the particles to achieve durability comparable to that of other companies’ partially hybrid columns.

Although the process is different, end-capping is also a form of silica surface modification. In fact, the highly inert treated silica column, Prominert, exhibits almost no difference in alkaline durability compared to partially hybrid columns.

For reference, SunArmor, launched in 2015, is analogous to partially hybrid columns.

Next, a comparison of the durability of partially hybrid columns (Company A–C) and fully hybrid columns (Company D, SunBridge) under an alkaline mobile phase (pH 11.5) is shown below.

The results indicate that fully hybrid columns exhibit significantly higher durability than partially hybrid columns. In particular, SunBridge showed no signs of degradation, even under harsh high-pH conditions.

Even under acidic conditions (pH 1), SunBridge demonstrates high performance. The surface inactivation treatment is believed to enhance stability by preventing the desorption of functional groups. Moreover, SunBridge surpasses existing fully hybrid columns (Company D) in terms of acid resistance.

For example, our SunShell (green color) exhibits significantly higher durability among core-shell columns, but SunBridge demonstrates an entirely different level of acid resistance in comparison.

The exceptional stability of SunBridge lies in its filler synthesis technology. The secret to SunBridge’s high stability is not only the use of ethylene-cross-linked silica gel but also the application of an advanced end-capping process that, so to speak, inactivates the filler both inside and out.

SunBridge is expected to be utilized not only under general mobile phase conditions but also in various demanding applications, such as ion-pair chromatography with high sample loads, continuous analysis, and preparative purification. 

An example of an analytical comparison of highly adsorptive compounds (chelating compounds and basic compounds) using SunBridge 5 μm and Company D’s 3.5 μm hybrid column is shown below.

In general, as particle size decreases from 5 μm to 3.5 μm, flow diffusion is suppressed, leading to an improvement in the theoretical plate number (N). However, if peak symmetry (TF) is compromised due to adsorption, the theoretical plate number also deteriorates, meaning that smaller particles do not necessarily result in a higher theoretical plate number.

For adsorptive compounds, the highly inert SunBridge 5 μm column exhibits a higher theoretical plate number than the 3.5 μm Company D column, which is affected by peak tailing. While both SunBridge and Company D fully hybrid columns demonstrate high durability, SunBridge has a significant advantage in terms of low adsorption.

This consistent column performance, which extends beyond a wide pH range, is what makes SunBridge an “ultra-hybrid” column that surpasses conventional fully hybrid columns.

 SunBridge C18 columns