Rxi-5HT

Rxi-5HT column

Restek Rxi-5HT GC Columns

Restek Rxi-5HT GC columns are engineered for extreme high-temperature GC applications requiring both rugged stability and MS-grade inertness. With a maximum operating temperature of 400–430 °C, Rxi-5HT columns deliver exceptional durability and minimized stationary-phase bleed—making them ideal for analyzing the heaviest, most thermally demanding compounds that exceed the limits of standard 5% phenyl columns.

Built on a thermally fortified silarylene-based polymer backbone, the Rxi-5HT stationary phase provides enhanced thermal resistance while maintaining the familiar selectivity of a classic 5% diphenyl, 95% dimethylpolysiloxane phase. This phase chemistry delivers reliable retention and sharp peak shapes for complex, high-boiling analytes including high-molecular-weight hydrocarbons, lubricants, plasticizers, phthalates, synthetic oils, flame retardants, polymer additives, and heavy semi-volatiles.

The extremely low bleed characteristics of Rxi-5HT are especially beneficial for GC-MS workflows, producing cleaner baselines, improved sensitivity, and more accurate identification of trace components in thermally challenging matrices. Its rugged construction and excellent lot-to-lot reproducibility make it well suited for routine high-temperature screening as well as advanced research applications.

As an authorized distributor of Restek products, Chrom Tech supplies Rxi-5HT columns in a wide range of dimensions to support petrochemical refining, materials testing, polymer analysis, specialty chemical manufacturing, and any workflow requiring maximum temperature endurance with consistent MS-grade performance.
Key Definitions ▸
High-Temperature (HT) GC Column
A GC column engineered to withstand oven temperatures above 350 °C and up to 430 °C, enabling elution of extremely heavy, thermally stable compounds that cannot be analyzed on conventional GC phases.
5% Phenyl, 95% Dimethylpolysiloxane Phase
A widely used low-polarity stationary phase offering versatile selectivity for hydrocarbons, semi-volatiles, additives, and complex matrices. Rxi-5HT uses a thermally reinforced variant of this chemistry for high-temperature operation.
Silarylene Reinforced Backbone
A strengthened polymer backbone that improves thermal resistance and minimizes bleed during intense temperature programming—critical for reliable GC-MS performance at high temperatures.
Ultra-Low Bleed
The ability of the stationary phase to resist thermal degradation, resulting in a cleaner baseline, higher sensitivity, and more accurate identification in GC-MS applications operating at extreme temperatures.
High-Boiling Compound Analysis
Analysis involving heavy hydrocarbons, polymers, additives, or thermally stable molecules that require elevated oven temperatures for complete elution. Rxi-5HT is designed for these demanding workflows.
Frequently Asked Questions ▸
What applications benefit most from Rxi-5HT columns?
Rxi-5HT is ideal for high-boiling hydrocarbons, flame retardants, phthalates, heavy additives, lubricants, polymer breakdown products, and high-temperature petrochemical or materials testing workflows.
Can Rxi-5HT columns be used with GC-MS?
Yes. Their extremely low bleed at very high temperatures provides the clean baselines and sensitivity required for demanding GC-MS applications involving heavy or high-molecular-weight analytes.
How does Rxi-5HT differ from Rxi-1HT columns?
Rxi-1HT uses a 100% dimethylpolysiloxane phase for nonpolar selectivity, while Rxi-5HT includes 5% phenyl groups for slightly increased polarity and improved resolution of certain additive and aromatic components.
Do Rxi-5HT columns provide long operational lifetimes at high temperatures?
Yes. The thermally reinforced polymer matrix is designed to resist degradation, extending column lifetime even under continuous high-temperature use and aggressive temperature programs.