16 Priority PAHs and Methylnaphthalenes on Rxi-5Sil MS using the GC Accelerator Kit in a 120 V Oven

Significance of the Topic

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants with known carcinogenic and mutagenic properties. Rapid, sensitive analysis of priority PAHs and their methylated analogs is essential for environmental monitoring, food safety, and regulatory compliance. Advances in gas chromatography–mass spectrometry (GC-MS) techniques, including the use of high-efficiency columns and specialized oven accessories, enable faster throughput and lower detection limits, supporting routine laboratory workflows and high-volume sample analysis.

Aims and Study Overview

The study evaluates the performance of the GC Accelerator Kit in a 120 V oven configuration for the separation and quantitation of 16 EPA priority PAHs plus 2-methylnaphthalene and 1-methylnaphthalene. Key goals include achieving baseline separation within a short analysis window, validating quantitation accuracy using internal standards and surrogate mixture spikes, and demonstrating applicability of a fast single-ion monitoring (SIM) method for trace-level detection.

Methodology

The analytical protocol employs a Restek Rxi-5Sil MS column (20 m × 0.15 mm ID, 0.15 µm film) installed in an Agilent 7890B GC coupled to a 5977A MSD.

• Sample Preparation: EPA Method 8310 PAH standard mixture and methylnaphthalenes in dichloromethane.
  
• Injection Conditions: 1 µL split injection (20:1) at 275 °C using a Topaz 4 mm single taper liner with wool.
  
• Oven Program: Hold 60 °C for 0.7 min; ramp to 285 °C at 39.8 °C/min; to 305 °C at 4.3 °C/min; to 320 °C at 28.5 °C/min, hold 3.5 min.
  
• Carrier Gas: Helium, constant flow at 1.0 mL/min.
  
• Mass Spectrometry: SIM mode with 10 groups, targeted ions for each analyte, solvent delay of 1 min, ionization by EI, source at 330 °C, quad at 180 °C.
  

Primary Results and Discussion

The optimized method achieved complete resolution of all compounds within a 10.6 min run time. Retention times ranged from 3.44 min for the naphthalene-d8 internal standard to 10.58 min for benzo[ghi]perylene. Separation efficiency remained high despite the rapid temperature program, with valley depths exceeding 70 % for critical pairs. Quantitative linearity was confirmed at 1 µg/mL levels, corresponding to on-column loads of 0.05 ng. SIM acquisition provided high sensitivity and selectivity, with dwell times tailored to each ion set to maximize signal-to-noise ratios.

Benefits and Practical Applications

By reducing cycle times to approximately 11 minutes, laboratories can increase sample throughput without compromising chromatographic performance. The method’s sensitivity supports regulatory limits for PAHs in water, soil, and food matrices. Use of deuterated internal standards and surrogate spikes ensures robust quantitation and compensates for matrix effects. The approach is suitable for environmental monitoring, quality control in petrochemical industry, and forensic investigations of combustion residues.

Future Trends and Potential Applications

Further enhancements may include integration with automated sample handling systems to support 24/7 operation. Coupling with high-resolution accurate-mass MS detectors could expand analyte scope to emerging contaminants. Miniaturized GC columns and advanced oven technologies may drive even faster separations, enabling on-site and mobile field analysis. Data processing using machine learning algorithms could further improve peak identification and quantitation in complex matrices.

Conclusion

The GC Accelerator Kit in a 120 V oven, combined with a narrow-bore Rxi-5Sil MS column and fast SIM detection, delivers rapid, reliable analysis of 16 priority PAHs and methylnaphthalenes. High chromatographic resolution, low detection limits, and robust quantitation make this method ideal for high-throughput laboratories focused on environmental and industrial applications.

Instrumentation

• Gas Chromatograph: Agilent 7890B GC with 120 V oven and GC Accelerator Kit.
  
• Column: Rxi-5Sil MS, 20 m × 0.15 mm ID, 0.15 µm film.
  
• Mass Spectrometer: Agilent 5977A MSD, EI source, quadrupole analyzer.
  
• Liner: Topaz 4 mm single taper with wool.