Screening PAHs in Soil Using RTL Database with SampliQ QuEChERS Extraction Kits and Agilent 5975T LTM GC/MS

Importance of the Topic

Polycyclic aromatic hydrocarbons are persistent environmental pollutants that accumulate in soil and pose health risks due to carcinogenicity. Regulatory agencies target a group of 16 PAHs as priority compounds. Fast and reliable screening methods are essential for environmental monitoring and risk assessment in soil matrices.

Objectives and Overview of the Study

This work describes the development of a rapid screening procedure for the 16 EPA priority PAHs in soil using a portable GC/MS system with retention time locking and a simplified QuEChERS extraction workflow. The approach aims to combine fast sample preparation with automated chromatographic peak identification and confirmation.

Methodology and Instrumentation

Sample pretreatment was based on QuEChERS extraction and dispersive cleanup. A 5 gram soil sample was hydrated, extracted with acetonitrile containing QuEChERS salts, and cleaned using PSA and C18 sorbents. The extract was filtered and injected into an Agilent 5975T LTM GC/MSD equipped with a 7693 autosampler and an Agilent J W LTM HP 5ms column. The GC method used splitless injection, helium carrier gas, and a temperature program from 70 to 300 °C. Retention times were locked to pyrene at 19.38 minutes using built in RTL software. Full scan mass spectra (80–350 u) were acquired under electron ionization.

Main Results and Discussion

Retention time locking delivered correlation coefficients between 0.9995 and 0.9999 for all PAHs. System repeatability over ten injections showed RT RSD below 0.04 percent. The RTL screening library enabled automated detection of all 16 PAHs in less than one minute per sample. Deconvolution software isolated target compounds at concentrations down to 0.01 microgram per gram in soil. QuEChERS cleanup significantly reduced matrix interferences, especially for late eluting high molecular weight PAHs.

Benefits and Practical Applications

The combined workflow offers rapid and reliable screening with minimal solvent and consumable use. The portable GC/MS system is suitable for field and mobile laboratories, enabling on site decision making. Retention time locking ensures consistent compound identification across instruments and laboratories.

Future Trends and Potential Applications

Future directions include expanding retention time locked libraries for other pollutant classes, integrating automated data processing for high throughput, and coupling portable GC MS with real time reporting systems. Advances in miniaturized instruments and greener extraction methods will further enhance field deployable analysis.

Conclusion

This application demonstrates an efficient protocol for PAH screening in soil using QuEChERS extraction, retention time locked GC MS, and automated data processing. The method achieves rapid turnaround, high repeatability, and low detection limits, supporting environmental monitoring and regulatory compliance.

Reference

• Frank David, Pat Sandra and Philip L Wylie, Improving the Analysis of Organotin Compounds using Retention Time Locked Methods and Retention Time Databases, Agilent Technologies publication 5988 9256EN
• Micheal J Szelewski, Kenneth R Weiner and Chin Kai Meng, Building and Editing RTL Screener Quant Databases and Libraries, Agilent Technologies publication 5989 0916EN
• Philip L Wylie, A Rapid GC MS Solution for the Japanese Positive List Pesticide Method, Agilent Technologies publication 5989 9320EN