Rxi Manufacturing

Rxi Columns: Built for Your Continued Success

We know that as a customer, it is incredibly important to you that your suppliers are honest when they make a claim. As fellow scientists, it is also very important to us that we are honest in order to maintain our credibility and adhere to our principles. That is why Restek has complete control of our Rxi column production stream—to ensure that you will receive a top-quality product that performs the way we promised it would, every time. As a result, Rxi columns come with an unbeatable guarantee: Restek Pure Satisfaction.

Fused Silica:

It is absolutely critical that we ensure adequate supply and utmost quality of our raw materials, and for most Rxi columns, that starts with the foundation of this exemplary product line: fused silica. We draw our own fused silica tubing to exacting specifications, and during the drawing process, we apply our own polyimide resin. By applying multiple layers of resin, we improve stability at higher temperatures and widen the application range of the fused silica tubing.


Once a batch of fused silica tubing is drawn, it must then be deactivated before it is worthy of becoming an Rxi column. Our surface deactivation technology and proprietary processes effectively shield silanols to ensure comprehensive inertness for polar compounds as well as acids and bases, providing symmetric peaks for higher sensitivity.

Phase Chemistry:

In addition to producing our own raw materials, we also develop our own proprietary stationary phases. Our California-based research facility, "Restek West," is charged with focusing on capillary column phases and deactivations. It is this skilled and dedicated team that creates the optimized polymers with the enhanced selectivities you need for the most challenging separations. Each Rxi phase is cross-linked to the deactivated fused silica tubing, creating a layer with strong mechanical characteristics and resulting in a long-lasting and rugged final product. This unique bonding technology ensures low bleed for higher sensitivity and reproducible retention times. From the widely used Rxi-5Sil MS to the specialty Rxi-PAH, our Rxi phases are developed and applied to your finished product in our own facility to better control quality and address your specific needs.

Quality Control:

All Rxi columns are guaranteed to exhibit reliable column-to-column reproducibility and low bleed because we individually test every column for inertness, selectivity, film thickness, efficiency, and bleed—measuring the results against strict QC specifications. Rxi columns are never batch tested. The critical performance values, including bleed, that we obtain with our tests are listed on the chromatographic test report included with your Rxi column. Every Rxi column that leaves our facility has been proven to meet or exceed the most stringent requirements.

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