Rtx-502.2

Rtx-502.2 Column

Restek Rtx-502.2 GC Columns

Restek Rtx-502.2 GC columns are engineered specifically for U.S. EPA Method 502.2 and related workflows targeting purge-and-trap volatile organic compounds (VOCs). Featuring a proprietary Crossbond 6% cyanopropylphenyl, 94% dimethylpolysiloxane stationary phase, Rtx-502.2 provides optimized selectivity for resolving critical volatiles—including halogenated hydrocarbons, oxygenates, and industrial solvents—while maintaining long-term performance stability.

This mid-polarity phase offers strong retention and separation of challenging analytes such as bromochloromethane, dichlorodifluoromethane, vinyl chloride, bromoform, 2-butanone, and carbon tetrachloride. Its balanced polarity profile enhances elution order and selectivity for isomeric and co-eluting VOCs frequently encountered in environmental water testing.

With low bleed, excellent inertness, and robust thermal stability, Rtx-502.2 supports reliable quantitation in GC and GC-MS methods that require consistent detection limits, sharp peak symmetry, and high sensitivity. The column’s reproducibility makes it ideal for validated EPA workflows, high-throughput testing, and regulated environmental laboratories.

As an authorized Restek distributor, Chrom Tech supplies Rtx-502.2 columns in a range of configurations to meet VOC analysis demands in environmental, industrial, and municipal water testing programs.
Key Definitions ▸
EPA Method 502.2
A purge-and-trap GC method for identifying and quantifying volatile organic compounds (VOCs) in drinking water and groundwater. Rtx-502.2 columns are optimized to meet this method’s selectivity and sensitivity requirements.
6% Cyanopropyl Phenyl Phase
A stationary phase combining aromatic and dipole interaction strength to enhance separation of halogenated, oxygenated, and polar VOCs commonly targeted in purge-and-trap environmental methods.
Purge-and-Trap VOC Analysis
A preconcentration technique used to extract volatile organic compounds from water samples before GC or GC-MS analysis, requiring columns with strong inertness and consistent selectivity.
Optimized VOC Selectivity
Rtx-502.2 provides targeted resolution for halogenated solvents, oxygenated volatiles, and industrial pollutants, improving identification and quantitation accuracy in complex matrices.
Low Bleed for GC-MS
Engineered for clean baselines and low column bleed at elevated temperatures, improving signal-to-noise ratios and extending column life in GC-MS workflows.
Frequently Asked Questions ▸
Which applications are best suited for Rtx-502.2 columns?
Rtx-502.2 is optimized for purge-and-trap VOC methods, particularly EPA 502.2, 524.2, and related water-testing workflows requiring strong resolution of halogenated and oxygenated volatiles.
How does Rtx-502.2 differ from Rtx-624 or Rxi-624Sil MS?
Rtx-502.2 offers stronger selectivity for halogenated and small oxygenated VOCs, while 624-type phases provide broader mid-polarity performance across general VOC classes. Many labs use 502.2 specifically for EPA compliance.
Is Rtx-502.2 column bleed low enough for GC-MS?
Yes. Rtx-502.2 is widely used with GC-MS for purge-and-trap VOC work because it delivers stable baselines and reliable sensitivity across typical VOC temperature programs. As with any VOC column, proper conditioning, leak-free connections, and clean carrier gas help minimize background and maintain consistent performance over time.
What carrier gas and flow settings are commonly used?
Helium is most common for purge-and-trap VOC methods, typically operated at constant flow to support retention-time stability. A good starting point is to target an average linear velocity appropriate for your column ID and instrument method, then fine-tune using your method’s QC criteria (resolution, RT windows, and peak shape).
Do I need a guard column for Rtx-502.2 VOC analysis?
Guard columns are optional but can be helpful when samples contain contaminants that shorten column life. In many purge-and-trap workflows, protecting the analytical column is achieved through clean trapping, dry purging, proper bake-out, and routine maintenance of transfer lines and traps. If your lab sees frequent contamination or active-site issues, a short guard segment can reduce downtime.
How can I extend column lifetime and maintain EPA method performance?
Maintain high-purity carrier gas and moisture/oxygen traps, confirm leak-free connections, and follow your method’s conditioning and bake-out guidance. Keep transfer lines and the purge-and-trap system clean, avoid overloading the column with dirty matrices, and replace traps/consumables on schedule. These practices help preserve retention-time stability, resolution, and low background for VOC compliance runs.