Restek Rxi Fused Silica Columns

What is Inertness in Gas Chromatography Columns?

When we speak about an inert GC column we are referring to the lack of reaction between the column and the sample molecules. The sample will pass smoothly through the column without loss of sample, sample breaking down or distorting of the peak shapes.

Why is Column Inertness Important?

The importance of an inert GC Column comes down to crisp resolution of your peaks, small peaks will be more readily visible and confidence in your results.

As a response to the need for column inertness Restek created the Rxi^® (extremely inert) Fused Silica GC Columns. Analysts around the world rely on Rxi GC columns, in general-purpose & specialty phases, for accurate, reliable results.

Outstanding Inertness

Restek's 3-in-1 technology produces such inert columns that they named them Restek eXtreme Inertness (Rxi). This extreme inertness improves signal-to-noise ratios and, therefore, your ability to consistently identify and quantify compounds in real-world samples. Inertness is especially important for the ever-lower detection limits required by testing regulations because many acidic, basic, and polar compounds tail significantly if your column has active sites (Figure 1). The remarkable inertness of Rxi technology solves this problem and allows a wide range of compounds to be analyzed with high sensitivity, often on a single column!

(Figure 1)

Low Bleed

This high performance column family of fused silica capillary columns are very low bleed and exhibit exceptional inertness for active compounds, both basic and acidic. These columns were engineered for low-level analysis using new deactivation techniques and polymer cross-bonding technologies.

The Rxi column being an ultra-low bleed column improves detection for trace level GC/MS analysis. Ultra-low bleed also reduces conditioning time after instrument maintenance.

Rxi columns are more stable than other manufacturers’ columns, so they generate less bleed (Figure 2) and reduce background to further improve signal-to-noise ratios, enhance sensitivity, and lower detection limits. These qualities make low-bleed Rxi columns the perfect choice for trace-level analyses. In addition, decreased contamination from bleed makes them ideal for sensitive detection systems like mass spectrometry (MS), where you will also benefit from better matches to mass spectral libraries.

Comparison of 30m x 0.25mm ID, 0.25µm columns. Bleed was compared at 330°C through 350°C; hydrogen carrier gas; flame Ionization detection.

(Figure 2)

High Reproducibility

Consistency is reliability. With Rxi column technology, Restek guarantees it. Every new column will perform exactly as the column it replaces.

Unpredictable retention times and shifting peaks can be frustrating at best and bring your work to a dead stop at worst. Unmatched manufacturing precision and stringent quality control mean that every Rxi column performs the same way as the column it replaces, every time you run it. They consistently exceed industry standards as measured by efficiency, retention, bleed, and inertness (Figure 3).

(Figure 3)

The Rxi family includes many popular phases that should satisfy all your GC separation needs.

Rxi-1301Sil MS GC Capillary Column

Cyano-based 1301 columns are general use GC columns that are well suited for the analysis of solvents across a range of volatilities. The cyano stationary phase provides more retention of polar compounds than a 5-type column; however, cyano-based stationary phases are prone to high bleed and poor robustness, limiting their utility. The Rxi-1301Sil MS column from Restek is a silarylene-based cyano stationary phase that not only provides the column selectivity needed for analyzing less volatile compounds, but also significantly lowers column bleed and improves robustness.

The low maximum operating temperature that is characteristic of non-silarylene cyano phases is a well-known drawback to using traditional 1301 columns for volatiles analysis. Due to their high bleed and low maximum temperatures, many 1301 columns do not perform well for MS analyses. In contrast, the robust Rxi-1301Sil MS column works extremely well for MS applications because it offers the highest maximum temperature and lowest bleed in the industry, leading to much more reliable and accurate MS results. Exceptionally high thermal stability produces robust column performance and allows for more aggressive thermal ramping to eliminate carryover of high molecular weight compounds between analyses (i.e., increased uptime).

In addition to providing both true 1301 selectivity and the lowest bleed/highest temperature limits in the industry, the Rxi-1301Sil MS column is designed to provide a high degree of inertness. Each Rxi-1301Sil MS column is tested with a QC mix that includes both acidic and basic probes to ensure inertness across multiple compound classes. Greater column inertness improves peak shape and response, ensuring more accurate quantitative results.

The Rxi-1301Sil MS column is ideal for the analysis of multiple compound classes across a range of polarities and volatilities. With its cyano-based selectivity and high thermal stability, it is the best 1301-type column for robust MS analyses.

Highest thermal stability in the industry ensures dependable, accurate MS results and increased uptime.
Stabilized cyano phase selectivity improves the performance of existing methods. Ideal for terpenes, glycol ethers, and other polar compounds.
Rigorous QC testing ensures inertness and accurate, reliable data for multiple compound classes.
Temperature range: -60°C to 320°C.

Rxi-17 GC Capillary Column

General-purpose columns for pesticides, herbicides, PAHs, rosin acids, phthalate esters.
Equivalent to USP G3 phase.
Temperature range: 40°C to 320°C.

Rxi-17Sil MS GC Capillary Column

Excellent inertness and selectivity for active environmental compounds, such as PAHs.
Low bleed for use with sensitive detectors, such as MS.
340/360°C upper temperature limits.
Equivalent to USP phase G3.

Rxi-1HT GC Capillary Column

Ideal for high-temperature applications, such as high molecular weight hydrocarbons.
Temperature range: -60°C to 400°C.
Equivalent to USP G1 and G2 phases.

Rxi-1ms GC Capillary Column

General-purpose columns for arson accelerants, essential oils, hydrocarbons, pesticides, PCB congeners (e.g., Aroclor mixes), sulfur compounds,
solvent impurities, simulated distillation, oxygenates, gasoline range organics (GRO).
Tested and guaranteed for ultra-low bleed; improved signal-to-noise ratio for better sensitivity and mass spectral integrity.
Temperature range: -60°C to 330/350°C.
Equivalent to USP G1, G2, and G38 phases.

Rxi-35Sil MS GC Capillary Column

The higher aromatic content of the Rxi-35Sil MS column allows for superior separation of cannabinoids over traditional 5-type columns. Baseline separation can be achieved for a comprehensive list of cannabinoids by using a cost-effective 15 m column and readily available hydrogen carrier gas. The arylene content of the Rxi-35Sil MS stationary phase ensures long column lifetime at the high elution temperatures required for cannabinoids analysis.

Special selectivity and excellent inertness for substituted polar compounds, such as drugs, pesticides, herbicides, PCBs, phenols, etc.
Provides superior separation for cannabinoids.
Very low-bleed phase for GC-MS analysis.
Extended temperature range: 50°C up to 360°C.

Rxi-5HT GC Capillary Column

Columns designed for high-temperature applications, such as mineral oil.
Temperature range: -60°C to 400°C.

Rxi-5ms GC Capillary Column

Ideal for pesticides in food.
General-purpose columns that can be used for phenols, residual solvents, drugs of abuse, pesticides, semivolatiles, PCB congeners (e.g., Aroclor mixes),
and solvent impurities.
Tested and guaranteed for ultra-low bleed; improved signal-to-noise ratio for better sensitivity and mass spectral integrity.
Temperature range: -60°C to 330/350°C.
Equivalent to USP G27 and G36 phases.

Rxi-5Sil MS GC Capillary Column

The Rxi-5Sil MS stationary phase incorporates phenyl groups in the polymer backbone. This improves thermal stability, reduces bleed, and makes the phase less prone to oxidation. Rxi-5Sil MS columns are ideal for GC-MS applications.

General-purpose columns for GC-MS analysis of most semivolatiles, polycyclic aromatic compounds, chlorinated hydrocarbons, phthalates, phenols, amines,
organochlorine pesticides, organophosphorus pesticides, drugs, solvent impurities, and hydrocarbons.
Engineered to be a low-bleed GC-MS column.
Excellent inertness for active compounds.
Temperature range: -60°C to 350°C.
Some dimensions also available as Integra-Guard columns – a guard and analytical column in one to eliminate connection problems!

Rxi-624Sil MS GC Capillary Column

Low-bleed, high-thermal stability column – maximum temperatures up to 300-320°C.
Inert – excellent peak shape for a wide range of compounds.
Selective – G43 phase highly selective for volatile organics, terpenes, and residual solvents, great choice for USP<467>.
Manufactured for column-to-column reproducibility – well suited for validated methods.
Temperature range: -20°C to 320°C.

Rxi-LAO GC Capillary Column

Specifically applicated for linear alpha olefins (LAO) impurity analysis, Rxi-LAO columns provide accurate analysis of LAO compounds including
1-butene, 1-hexene, and 1-octene. Combining a stationary phase with a unique selectivity and an optimal, one-column method, these new columns
help improve your LAO analysis by increasing system uptime and sample throughput.

Specifically applicated for linear alpha olefin (LAO) impurity analysis.
Unique selectivity enables high resolution of impurities from peaks of interest.
One-column method reduces instrument setup and analysis time.
Consistent column-to-column performance.
Engineered to be a low-bleed column.

Rxi-PAH GC Capillary Column

The Rxi-PAH GC columns were designed by Restek with a higher phenyl-content stationary phase that provides unique selectivity to separate important polycyclic aromatic hydrocarbons (PAH) for food safety that cannot be distinguished by mass spectrometry. Even difficult priority compounds, such as the European Food Safety Authority (EFSA) PAH4, are easily separated and accurately quantified – results that cannot be achieved on typical GC columns. Arylene modification and surface bonding of the stationary phase increase thermal stability and ruggedness so relatively nonvolatile, higher molecular weight PAHs can be analyzed routinely without interference from column bleed. Excellent column efficiency means that the column can be trimmed for maintenance purposes many times without losing critical PAH separations, including those that are part of food safety testing. The selectivity and efficiency of the Rxi-PAH column make it ideal for EFSA PAH4 analysis; chrysene/triphenylene separation and resolution of all benzofluoranthenes are easily achieved.

Note:
Product # RK49316: Narrow inside diameter, thinner film, faster analysis, excellent separation of important PAHs, less sample loading capacity.
Product # RK49317: 0.25 mm inner diameter, better sample loading capacity, highest resolution of important PAHs, longer analysis than 0.18 mm column,
thin film allows elution of dibenzo pyrenes.
Product # RK49318: 0.25 mm inside diameter, better sample loading capacity, faster analysis time than 60m column, adequate resolution of important PAHs,
lower cost column.

Ideal for EFSA PAH4 analysis – separates all priority compounds: benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene.
Best resolution of chrysene from interfering PAHs, triphenylene, and cyclopenta[cd]pyrene.
Complete separation of benzo [b], [k], [ j], and [a] fluoranthenes.
40°C to 360°C thermal stability allows analysis of low-volatility dibenzo pyrenes.

Rxi-SVOCms GC Capillary Column

Rxi-SVOCms columns keep your instrument online and analyzing semivolatiles (SVOC) samples instead of offline for time-consuming recalibration or column replacement. Designed specifically for improved semivolatiles performance, Rxi-SVOCms columns ensure consistent chromatography that will keep calibrations passing longer, so you can run more samples before needing to recalibrate the instrument or replace the column.

Column chemistry optimized specifically to give premium performance for semivolatiles in complex matrices.
Long column lifetime – restore performance with a quick trim instead of a time-consuming replacement.
Outstanding inertness keeps calibrations passing and samples running.
Excellent resolution of critical pairs for improved accuracy.
Consistent column-to-column performance.
Engineered to be a low-bleed GC-MS column.
Temperature range: -60°C to 340 °C.
Equivalent to USP G27 and G36 phases.

Simplify calibration with SVOC MegaMix reference standards kits that contain 150 (product # RK31907) or 100 (product # RK31908) of the most frequently analyzed semivolatiles.

Rxi-XLB GC Capillary Column

Improvements in polymer synthesis and tubing deactivation enable us to make inert, stable Rxi-XLB columns especially well-suited for analyzing active, high molecular weight compounds with sensitive GC-MS systems, including ion trap detectors. Excellent efficiency, coupled with inertness, low bleed, and high thermal stability, make Rxi-XLB columns ideal for analyzing semivolatile compounds in drinking water.

Rxi-XLB columns are a great choice for semivolatile organics analysis by EPA Method 525.2. An Rxi-XLB column plus some simple adjustments to the injection conditions can greatly improve sensitivity for active and high molecular weight Method 525.2 target compounds.

General-purpose columns with unique selectivity. Ideal for many GC-MS applications, including pesticides, PCB congeners (e.g., Aroclor mixes), PAHs.
High thermal stability; exhibits extremely low bleed.
Temperature range: 30°C to 360 °C.

To Learn More About the Restek Products View Their Catalogue.

Still Have Questions?

You can give us a call or email us and we can find the right Fused Silica GC Column product number for your application. It's our pleasure to help you and it's free!

1-800-267-8103 or tech@chromspec.com