Increased Reproducibility in the Analysis of EU and EPA PAHs with the Agilent J&W Select PAH GC Column and Agilent Intuvo 9000 GC

Importance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are priority environmental pollutants regulated by both the European Union and the US Environmental Protection Agency due to their toxicity and persistence. Accurate quantification of PAHs at low nanogram per milliliter levels in complex, high–fat matrices such as salmon oil is essential for environmental monitoring, food safety, and industrial quality control.

Objectives and Study Overview

This study aimed to evaluate the performance of the Agilent J&W Select PAH GC column in combination with an Agilent Intuvo 9000 GC for the separation and detection of 25 PAH isomers (including triphenylene) required by EU and EPA methods. A comparative assessment with a conventional Agilent 7890 GC system was conducted to determine improvements in sensitivity, resolution, retention time stability, and reproducibility under repeated injections of a salmon oil matrix.

Methodology

Standard solutions of 24 regulated PAHs and triphenylene were prepared at 20 mg/mL and diluted to 1–2 mg/mL in dichloromethane. Salmon oil samples were diluted 1:10 in dichloromethane and injected at intervals of 50 injections. Both systems used selected ion monitoring (SIM) on a 5977B mass selective detector. The temperature program included an initial hold at 70 °C, rapid ramps to 180 °C, then to 230 °C, 280 °C, and a final ramp to 330 °C. Helium was the carrier gas at 1.2 mL/min, and injections were performed in splitless mode at 300 °C.

Used Instrumentation

• Agilent 7890B GC with split/splitless inlet and 5977B GC/MSD
• Agilent Intuvo 9000 GC with planar microfluidic column modules
• Agilent J&W Select PAH GC column (30 m × 0.25 mm, 0.15 µm film thickness)
• Intuvo Intuvo GC column module and Guard Chip (metal microfluidic inlet seal and guard column)
• Agilent 7693A automatic liquid sampler and MassHunter software

Main Results and Discussion

Both the conventional 7890 and the Intuvo 9000 GC systems achieved baseline separation of all 25 PAHs under SIM conditions. Repeated injections of diluted salmon oil on the 7890 GC led to contamination of the inlet liner, gold seal, and septum, causing significant loss of sensitivity and retention time shifts after maintenance. In contrast, the Intuvo 9000 GC’s replaceable Guard Chip maintained consistent retention times and sensitivity, even after extensive matrix injections. Chromatograms from both systems under identical conditions showed nearly identical peak shapes and heights, with the Intuvo offering superior reproducibility.

Benefits and Practical Applications

• Guard Chip technology minimizes downtime by simplifying front-end maintenance and preserving retention time stability.
• Enhanced reproducibility and sensitivity support compliance with stringent regulatory limits.
• Applicability to complex environmental and food matrices reduces method development time and maintenance frequency.

Future Trends and Potential Applications

Microfluidic and planar column technologies are expected to expand into other challenging analyte classes beyond PAHs, with further automation of maintenance modules to reduce manual interventions. High-throughput environmental screening, food safety monitoring, and industrial QA/QC stand to benefit from these developments.

Conclusion

The combination of the Agilent J&W Select PAH GC column with the Agilent Intuvo 9000 GC delivers robust separation, stable retention times, and enhanced reproducibility for the analysis of 25 PAHs in difficult, high-fat matrices. Guard Chip technology effectively addresses retention shifts, reduces maintenance efforts, and supports consistent method performance.

References

1. Lynman, K. PAH Analysis with High Efficiency GC Columns: Column Selection and Best Practices. Agilent Technologies, publication number 5990-8572EN, 2010.
2. Lucas, D.; Zhao, L. PAH Analysis in Salmon with Enhanced Matrix Removal. Agilent Technologies, publication number 5991-6088EN, 2015.
3. Oostdijk, J. Separation of 54 PAHs on an Agilent J&W Select PAH GC Column. Agilent Technologies, publication number SI-02232, 2010.