Rtx-225

Rtx-225 column

Restek Rtx-225 GC Columns

Restek Rtx-225 GC columns are engineered for enhanced selectivity toward polar, multifunctional, and structurally similar analytes that are often difficult to separate on conventional mid-polarity phases. Featuring a unique 50% cyanopropylphenyl, 50% dimethylpolysiloxane stationary phase, Rtx-225 provides a significantly higher polarity compared to 1301, 1701, and 624 phases—resulting in powerful retention for acids, esters, alcohols, amines, nitro compounds, and other active or polarizable species.

This high-polarity phase allows laboratories to achieve improved resolution of critical isomers and compounds with minimal boiling point differences. Rtx-225 is especially effective in workflows involving fatty acid methyl esters (FAMEs), flavor and fragrance profiles, industrial solvents, glycols, and complex environmental pollutants. Its enhanced dipole and hydrogen-bonding interactions provide separation power that standard cyano or phenyl phases cannot match.

With strong inertness, low bleed, and robust thermal stability, Rtx-225 supports both GC and GC-MS workflows requiring consistent peak shape and high-quality quantitation. This phase is frequently selected for detailed characterizations, impurity profiling, complex mixture analysis, and regulatory workflows that demand precise resolution of polar compounds.

As an authorized distributor of Restek GC columns, Chrom Tech provides Rtx-225 in multiple lengths, IDs, and film thicknesses—supporting method development, routine analysis, and advanced applications requiring a high-polarity, high-resolution GC stationary phase.
Key Definitions ▸
50% Cyanopropylphenyl Stationary Phase
A highly polar GC phase containing a 50% cyanopropylphenyl substitution, offering significantly stronger interactions with polar, acidic, and multifunctional analytes than standard mid-polarity phases.
High-Polarity Selectivity
Selectivity dominated by dipole, hydrogen-bonding, and polar interactions—ideal for resolving alcohols, acids, esters, nitro compounds, glycols, and complex flavor/fragrance components.
FAME Analysis Optimization
Rtx-225 provides excellent separation of fatty acid methyl ester isomers, making it suitable for food, biodiesel, and lipid research workflows requiring high resolution.
Dipole & Hydrogen-Bonding Retention
The mechanism by which Rtx-225 retains polar analytes more strongly than non-polar phases, enabling separation of acids, glycols, alcohols, and other polar species with similar boiling points.
Rtx® Deactivation
Restek’s proprietary surface treatment reduces analyte adsorption and improves recovery of reactive, acidic, and polar compounds—ensuring accurate quantitation and sharp peaks.
Frequently Asked Questions ▸
What makes Rtx-225 different from other Restek mid-polarity columns?
Rtx-225 has a significantly higher polarity (50% cyanopropylphenyl) than phases like 1301 or 1701, providing much stronger retention and improved separation of polar, acidic, and multifunctional analytes.
Is Rtx-225 compatible with GC-MS?
Yes. The column’s low bleed and strong inertness make it highly suitable for GC-MS analysis of polar and reactive compounds—especially in environmental, food, and industrial methods.
What applications most commonly use Rtx-225?
Rtx-225 is widely used for fatty acid methyl ester (FAME) profiling, flavor and fragrance analysis, industrial solvent characterization, glycol separations, and environmental testing of polar or reactive chemicals.
When should I choose Rtx-225 over Rtx-20 or Rtx-200?
Choose Rtx-225 when you need significantly higher polarity, stronger dipole interactions, or enhanced separation of multifunctional, acidic, or polar compounds that are not well resolved on Rtx-20 or Rtx-200.