Analysis of Semivolatiles by GC/FID using the Ultra Inert Inlet Liners with Wool

Importance of the Topic

Semivolatile organic compounds are extensively monitored in environmental, industrial and forensic applications due to their toxicity and persistence. Accurate quantitation by gas chromatography with flame ionization detection (GC/FID) depends on an inert sample inlet that prevents adsorption and degradation. Traditional glass wool inlet liners enhance vaporization and mixing but introduce active sites that compromise labile analytes. Agilent Ultra Inert deactivated glass wool liners overcome these limitations by providing robust deactivation across all inlet surfaces.

Objectives and Study Overview

This study evaluates the performance of Ultra Inert splitless inlet liners packed with deactivated glass wool under USEPA Method 8270 conditions. Key goals include:

• Assessing calibration linearity for representative active semivolatiles at low on-column masses (2–80 ng).
• Comparing liner-to-liner reproducibility across multiple lots.
• Evaluating thermal stability at 330 °C over 10 days.
• Measuring injection repeatability over 100 consecutive injections.
• Benchmarking against competitor deactivated wool liners and inert liners without wool.

Methodology and Instrumentation

Standards and reagents: EPA 8270 custom semivolatile standard and internal standards in methylene chloride. Calibration levels spanned 2–80 µg/mL (2–80 ng on column) with a constant 40 µg/mL internal standard concentration. Instrumentation:

• Gas chromatograph: Agilent 7890 GC with 7683B autosampler.
• Detector: Flame ionization detector (FID) at 250 °C.
• Column: Ultra 2, 25 m×0.32 mm×0.52 µm film.
• Carrier gas: Helium at 3 mL/min constant flow.
• Inlet mode: Splitless, 250 °C, 30 mL/min purge at 1.5 min.
• Consumables: Agilent Ultra Inert deactivated single-taper splitless liners with wool, Vespel/graphite ferrules and advanced green septa.

Main Results and Discussion

Calibration linearity: All active analytes achieved response factor (RF) relative standard deviations (RSDs) below 15% over 2–80 ng on column, including challenging phenols and aromatic amines. Liner reproducibility across seven samples from four lots showed consistent RFs (e.g., 2,4-DNP RF avg. 0.277, RSD 13.1%). Thermal stability: After 10 days at 330 °C, RF variability remained under 7% for all targets. Injection repeatability: Over 100 injections at 5 ng on column, RF RSDs stayed below 6%. Comparative evaluation: Ultra Inert wool liners outperformed Restek Siltek and matched or exceeded Restek IP SemiVolatile and Sky liners in sensitivity and stability. Inert liners without wool delivered similar RFs but lacked matrix protection offered by wool packing.

Benefits and Practical Applications

Ultra Inert deactivated wool liners combine high inertness with homogeneous sample mixing, efficient vaporization of liquid analytes and trapping of nonvolatile residues. This protects the analytical column and detector from contamination and extends maintenance intervals. The liners support reliable quantitation of acids, bases and neutrals in complex environmental samples at sub-nanogram levels.

Future Trends and Potential Uses

Further improvements in deactivation chemistries and liner geometries may lower detection limits and broaden the range of compatible analyte classes. Integration with advanced automation, high-throughput workflows and alternative detectors (e.g., micro-FID, vacuum ultraviolet) will enhance robustness in environmental monitoring, food safety and forensic laboratories. Customized liners tailored to specific compound groups may provide additional selectivity and longevity.

Conclusion

Agilent Ultra Inert deactivated glass wool inlet liners deliver exceptional inertness, stability and repeatability for semivolatile GC/FID analysis under USEPA 8270 conditions. They exhibit superior calibration linearity, thermal robustness and injection repeatability compared with competitor liners, while offering enhanced protection of system components and reliable quantitation at trace levels.

References

1. M. Szelewski, B. Wilson, P. Perkins, Improvements in the Agilent 6890/5973 GC/MSD system for Use with USEPA Method 8270, Agilent Technologies Publication 5988-3072EN.
2. USEPA Method 8270D: Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry, U.S. EPA SW-846.
3. L. Zhao, A. Broske, D. Mao, Evaluation of the New Agilent Ultra Inert No Wool Liners for Active Compounds Analysis by GC, Agilent Technologies Publication 5990-7380EN.