Semivolatile Analysis Using an Inertness Performance Tested Agilent J&W DB-5ms Ultra Inert Column

Importance of Semivolatile Analysis and Column Inertness

Semivolatile compounds encompass a variety of acidic and basic species that readily interact with active sites in the gas chromatograph flow path, causing adsorption, peak tailing and sensitivity loss. Environmental monitoring of these analytes—often following USEPA 8270 protocols—requires both system and column inertness to achieve accurate quantitation and reproducible results.

Objectives and Study Overview

This work introduces a more stringent testing protocol for GC column inertness. The primary aims were to:

• Establish a robust inertness baseline using targeted probe compounds.
• Validate performance with challenging semivolatile analytes from environmental sample sets.
• Demonstrate the advantages of the Agilent J&W DB-5ms Ultra Inert column over conventional testing mixes.

Methodology and Used Instrumentation

The evaluation comprised two phases:

• Baseline inertness testing with aggressive probes—1-propionic acid, 4-picoline, trimethyl phosphate and 1-heptanol—at 1 ng on-column to assess surface activity.
• Application testing with semivolatile mixes drawn from USEPA 8270 standards, spanning acidic, basic and polycyclic aromatic hydrocarbons (PAHs), loaded at 5 ng on-column.

Main instrumentation and supplies included:

• Agilent 6890N GC with 7683B autosampler and FID detector.
• Agilent 6890N GC coupled to 5975B MSD for total ion monitoring.
• Agilent J&W DB-5ms Ultra Inert column (30 m×0.25 mm×0.25 µm).
• Consumables: deactivated inlet liners with glass wool, Advanced Green septa, Vespel/graphite ferrules, amber screw-cap vials, 5 µL syringes.

Main Results and Discussion

Baseline tests yielded sharp, symmetrical peaks for all aggressive probes, with only minor tailing for trimethyl phosphate—indicating excellent column inertness. In the semivolatile challenge:

• Response factors for 2,4-dinitrophenol exceeded 0.1 and for 4-nitrophenol exceeded 0.2 across the tested concentration range.
• Benzidine recoveries remained high at an optimized inlet temperature of 260 °C, balancing thermal stability and elution of higher-boiling PAHs.
• A comprehensive mix of 93 semivolatiles—from N-nitrosodimethylamine to benzo(g,h,i)perylene—showed consistent retention times, peak shapes and responses.

Benefits and Practical Applications

Implementing aggressive probe-based inertness testing provides environmental and QA/QC laboratories with:

• Reliable quantitation of active semivolatiles prone to adsorption losses.
• Reduced method development time by deploying columns with certified inertness baselines.
• Maintained sensitivity for both early-eluting nitrosamines and late-eluting PAHs in a single analysis.

Future Trends and Opportunities

Emerging directions may include:

• Expanded inertness protocols incorporating additional functional groups and probe molecules.
• Automation of inertness qualification during routine instrument maintenance.
• Novel stationary phase chemistries engineered for ultra-inert performance across diverse analyte classes.

Conclusion

Aggressive probe-based inertness testing elevates column qualification to a new industry standard. The Agilent J&W DB-5ms Ultra Inert column delivered exceptional performance for challenging semivolatile analytes, enabling accurate, reproducible and high-sensitivity environmental analyses.

References

1. US EPA Method 8270D, Revision 4, February 2007, Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS).
2. K. Grob Jr., G. Grob and K. Grob, Comprehensive, Standardized Quality Test for Glass Capillary Columns, Journal of Chromatography A, 156(1):1–20, 1978.
3. M. Hastings, A.K. Vickers and C. George, Inertness Comparison of Samples of 5% Phenyldimethylpolysiloxane Columns, Poster, 54th Annual Pittsburgh Conference, Orlando, FL, March 2003.
4. J. Luong, R. Gras and W. Jennings, An Advanced Solventless Column Test for Capillary GC Columns, Journal of Separation Science, 30(13):2480–2492, 2007.
5. M. Szelewski and B. Wilson, Improvements in the Agilent 6890/5973 GC/MSD System for Use with USEPA Method 8270, Agilent Technologies publication 5988-3072EN.