Polycyclic Aromatic Hydrocarbon (PAH) Analysis Using an Agilent J&W DB-5ms Ultra Inert Capillary GC Column

Significance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental pollutants generated by incomplete combustion of organic matter. They accumulate in soils, sediments and food products, posing potential health risks due to their carcinogenic properties. Accurate and sensitive analysis of trace and ultra trace PAH levels is essential for environmental monitoring and food safety assessment.

Objectives and Study Overview

The study aims to demonstrate the performance of an Agilent J&W DB-5ms Ultra Inert capillary GC column for trace-level PAH analysis. It introduces a rigorous inertness verification protocol using aggressive probe compounds and evaluates the column in conjunction with an electron impact single quadrupole GC/MS scanning system. The method is validated for a 16-component PAH standard over a concentration range from 0.05 to 5 micrograms per milliliter.

Methodology and Instrumentation

An Agilent 6890N GC coupled to a 5975B MSD with a 7683B autosampler was used. The column was a 30 m x 0.25 mm x 0.25 µm Agilent J&W DB-5ms Ultra Inert. Helium was the carrier gas at a constant linear velocity of 45 cm/s. Injection was pulsed splitless at 300 C with a 1 µL volume. The oven was programmed from 55 C to 320 C at 25 C per minute. MSD conditions included a 300 C ion source, 180 C quadrupole and 280 C transfer line, scanning from 45 to 450 AMU.

Inertness verification employed aggressive probe molecules such as 1-propionic acid, 4-picoline and trimethyl phosphate. For PAH analysis, a 16-component standard in acetone was prepared from a 500 µg/mL stock and serially diluted to concentrations of 5.0, 2.0, 1.0, 0.5, 0.1 and 0.05 µg/mL. Class A glassware and deactivated consumables were used throughout.

Results and Discussion

Baseline inertness testing confirmed minimal active sites in the Ultra Inert columns. The 16 PAHs were resolved in a 15-minute run, with only indeno[1,2,3-cd]pyrene and dibenz[a,h]anthracene partially coeluting. Sensitivity was high even in scan mode, with a signal-to-noise ratio above 9:1 for benzo[a]pyrene at 0.05 ng on-column. Calibration curves were linear with R2 values ≥ 0.995 for all analytes across the tested range.

Benefits and Practical Applications

The Ultra Inert column surface reduces adsorption of active PAHs, yielding more reliable results and lower detection limits. Rapid analysis times and strong linearity make this approach suitable for environmental quality assessments, food safety monitoring and regulatory compliance in trace PAH detection.

Future Trends and Potential Applications

Further improvements can be achieved by employing SIM/scan or full SIM modes to enhance sensitivity. Integration with advanced MS systems such as the Agilent 7890A GC and 5975C MSD Triple-Axis Detector may push detection limits lower. The method can be extended to complex sample matrices and high-throughput screening workflows.

Conclusion

The Agilent J&W DB-5ms Ultra Inert capillary column provides robust, sensitive and reproducible trace-level PAH analysis. Its inertness verification ensures consistent performance, leading to accurate quantification in challenging environmental and food matrices within a short analysis time.

References

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