Rxi®-5Sil MS Columns - Exceptionally Inert Columns for GC/MS and Trace-Level Analyses

Significance of the Topic

Gas chromatography coupled with mass spectrometry (GC/MS) is a cornerstone technique for trace-level analysis across environmental, food, clinical, and forensic laboratories. Column bleed, active sites, and batch-to-batch variability can compromise sensitivity, reproducibility, and quantitation, particularly for polar and low‐abundance analytes. The Rxi-5Sil MS fused silica column addresses these challenges through advanced polymer chemistry and rigorous quality control, ensuring consistent, high‐performance separations at trace detection levels.

Objectives and Study Overview

This document evaluates the Rxi-5Sil MS column’s performance relative to competing low‐bleed, phenyl/dimethyl polysiloxane and silarylene phases. Key goals include:

• Quantifying column bleed at elevated temperatures (up to 350 °C).
• Assessing inertness toward acidic and basic probes at low nanogram levels.
• Demonstrating column‐to‐column reproducibility across manufacturing lots.

Methodology and Instrumentation

Bleed profiles were recorded using a 1 ng n-tridecane internal standard, ramping the oven from 135 °C to 350 °C under helium flow and FID detection. Inertness tests involved 40 µg/mL solutions of 2,4-dinitrophenol and pyridine, tracking response factors and peak shapes at on-column loads of 2 ng. Reproducibility was evaluated using an 8-component test mix analyzed on four independent production batches.

Used Instrumentation

• Gas chromatograph: HP 5890 GC with FID at 320–330 °C.
• Carrier gas: Helium, constant flow 1.4 mL/min (bleed test) and 2.5 mL/min (inertness test).
• Split injection: 1.0 µL at 250 °C; split ratios 40:1 and 20:1.
• Column: Rxi-5Sil MS, 30 m × 0.25 mm ID × 0.25 µm film.

Main Results and Discussion

Compared to equivalent silarylene and phenyl/dimethyl phases, the Rxi-5Sil MS column exhibits the lowest bleed at 350 °C, yielding higher signal‐to‐noise ratios for trace analytes. In inertness evaluations, it produced superior response factors for both acidic (2,4-dinitrophenol) and basic (pyridine) probes with minimal peak tailing. Batch comparisons revealed highly reproducible retention times and peak shapes across four production lots, affirming tight manufacturing tolerances.

Benefits and Practical Applications

• Enhanced sensitivity and lower detection limits for GC/MS and ion trap systems.
• Reliable quantitation of acidic, basic, and polar compounds without derivatization.
• Consistent performance in method development and routine analysis, reducing downtime and validation efforts.

Future Trends and Opportunities

Developments in stationary-phase chemistry may further push thermal limits beyond 350 °C while maintaining ultra-low bleed. Integration with advanced guard systems and automated column conditioning routines can extend column lifetime. The continued miniaturization of GC platforms and adoption of hydrogen carrier gas will benefit from high-inertness, low-bleed phases like Rxi-5Sil MS.

Conclusion

The Rxi-5Sil MS fused silica column delivers industry-leading low bleed, exceptional inertness, and outstanding lot-to-lot reproducibility. It is optimized for demanding GC/MS and trace-level analyses, enabling laboratories to achieve lower detection limits, robust quantitation, and streamlined workflows.