It’s Peak Season for Great Peak Shape - Tips and tricks on troubleshooting in GC chromatography

Importance of the Topic

Gas chromatography peak shape critically influences chromatographic resolution, detector sensitivity, and quantitation accuracy. Systematic troubleshooting of peak shape anomalies is essential to minimize instrument downtime, reduce operational costs, and maintain high-quality data output in research, QA/QC, and industrial laboratories.

Objectives and Study Overview

This application note outlines a logical, stepwise approach to identify and correct common GC peak shape problems. It defines five key subsystems where issues can originate—injection, flow path, column, detector, and electronics—and presents diagnostic tests and real-world examples illustrating efficient fault isolation and remediation.

Methodology and Instrumentation

• Sample introduction: split/splitless inlet with Agilent 7693A autosampler and PTFE-tipped syringes to ensure inert flow and reproducible injections.
• Flow path isolation: bleed profiling (blank runs without injection), non-retained compound injections, and jumper-tube tests to localize contamination or leaks.
• Detector and electronic checks: FID baseline noise analysis, MS tuning, and carrier gas purity verification.
• Column and inlet hardware: evaluation and replacement of liners, ferrules, transfer lines, and Agilent J&W Ultra Inert GC columns.

Main Results and Discussion

• Common peak shape issues—tailing, fronting, split peaks, ghost peaks, noisy baselines, retention shifts, and resolution loss—are systematically categorized by subsystem of origin.
• Diagnostic workflows such as half-splitting the GC/MS system, condensation tests, and QC test mixes isolate injector, column, detector, or gas supply faults.
• Case studies demonstrate rapid resolution of no-peak events by replacing worn injector syringes, recovery of peak shape with new liners, and restoration of resolution through column maintenance.

Benefits and Practical Applications

• Structured troubleshooting reduces trial-and-error, saving time and consumables.
• Targeted part replacement extends column and inlet lifetimes and ensures consistent data quality.
• Improved methods reliability benefits trace analysis, environmental testing, food safety, and pharmaceutical QC workflows.

Future Trends and Opportunities

• Integration of automated diagnostic routines in GC software to guide users through troubleshooting tests.
• Advances in inert flow technologies and surface treatments to further minimize active sites and extend column performance.
• Application of machine learning to predict maintenance needs based on chromatographic trends and instrument logs.

Conclusion

A logical, subsystem-based troubleshooting approach—combining targeted diagnostic tests with stepwise hardware evaluation—enables fast identification of GC peak shape problems. Focusing on one variable at a time and leveraging bleed profiles, non-retained compounds, and jumper tube tests prevents unnecessary component replacement and maintains high-quality chromatographic performance.

Instrumental Setup Used

• Agilent 7890 GC with split/splitless inlet and Agilent J&W Ultra Inert columns.
• Agilent 7693A autosampler equipped with 10 µL PTFE-tipped syringes.
• Detectors: FID (flame ionization) or Agilent 5977A Extractor GC/MSD.
• Carrier gases: helium or hydrogen with gas purification traps.