Analysis of polynuclear aromatic hydrocarbons (PAH)

Importance of the topic

PAHs are a class of organic pollutants known for their persistence and potential health hazards, including mutagenicity and carcinogenicity.
Accurate separation and detection of these compounds are critical for environmental monitoring, food safety, and compliance with regulatory standards.

Objectives and overview

This application note describes a gas chromatography–mass spectrometry (GC–MS) method using a BPX50 column to separate and analyze 16 priority PAHs.
The aim is to achieve baseline resolution, short analysis times, and reliable quantitation at low concentration levels.

Methodology and approach

A dichloromethane solution of PAH standards (10 ng/µL) is injected in splitless mode (0.2 µL) onto a BPX50 capillary GC column (30 m × 0.25 mm × 0.25 µm).
The oven program initiates at 65°C, ramps to 140°C at 25°C/min, then to 325°C at 10°C/min, holding for 15 min.
Helium serves as the carrier gas at 1.1 mL/min under constant flow, while a mass spectrometer records the eluting analytes.

Instrumentation used

• Column: BPX50 (30 m × 0.25 mm × 0.25 µm; part no. 054751)
• Carrier gas: Helium, 9.7 psi, flow rate 1.1 mL/min
• Injection: splitless mode, 0.2 µL, injector at 250°C, double-taper liner (4 mm ID)
• Oven temperature program: 65°C (0.5 min), 25°C/min to 140°C, 10°C/min to 325°C (15 min)
• Detector: Mass spectrometer

Main results and discussion

All 16 PAHs, including naphthalene, benzo[a]pyrene, and indeno[1,2,3-cd]pyrene, are baseline separated within a 30-minute runtime.
Retention times are reproducible with high chromatographic efficiency, and the MS detection ensures selectivity and sensitivity at low nanogram levels.
The method exhibits consistent peak shapes and resolution exceeding regulatory requirements.

Benefits and practical use

• High resolution and sensitivity for trace-level quantitation
• Robust operation suitable for environmental and food-analysis laboratories
• Compliance with standard PAH monitoring protocols
• Applicability to routine QA/QC and research workflows

Future trends and opportunities

The integration of high-resolution MS and faster temperature programming can further reduce analysis time and improve detection limits.
Automation and online sampling techniques will enhance throughput, while the development of novel stationary phases may offer tailored selectivity for emerging contaminants.
Green solvent selection and miniaturized GC platforms represent additional areas for method optimization.

Conclusion

The described GC–MS method using a BPX50 column delivers reliable separation and quantitation of 16 PAHs at trace levels, meeting the needs of diverse analytical settings.
Its robustness and compliance with regulatory guidelines make it a valuable tool for environmental monitoring and quality control.

Reference

• Trajan Scientific Australia Pty Ltd. Application note AN-0121-G, December 2016.