DETERMINATION OF PAH via GPC with On-line EVAporation and HPLC-FLD Measurement

Significance of the topic

Efficient and automated analysis of polycyclic aromatic hydrocarbons (PAHs) in food samples is essential due to the toxic and carcinogenic nature of these contaminants. Regulatory compliance and public health protection demand reliable, high-throughput analytical workflows.

Objectives and study overview

This application note demonstrates a fully automated workflow combining gel permeation chromatography (GPC), on-line solvent evaporation (EVAporation), and high performance liquid chromatography with fluorescence detection (HPLC-FLD). The approach aims to streamline sample cleanup, concentration, solvent exchange, and analysis of PAHs in food extracts.

Methodology and instrumentation

Extracted, dried, and filtered food samples are adjusted to 10 milliliters and introduced into the FREESTYLE GPC system. A 5 milliliter aliquot is injected onto a GPC column, separating matrix interferences while directing eluting PAHs into an EVAporation module for on-line concentration. After evaporative removal of solvents, an automated solvent exchange to acetonitrile with 1 percent 1-butanol is performed, and the final 1 milliliter concentrate is collected in an HPLC vial.

Used Instrumentation

• FREESTYLE GPC system with EVAporation module
• FREESTYLE Basic platform
• HPLC system Thermo 3000 Ultimate with fluorescence detector
• GPC column and sample racks for 16 mL and GC vials

Main results and discussion

With the standard setup, total processing time including solvent exchange and vial filling is 1 hour 35 minutes. Recovery rates from triplicate experiments exceeded 83 percent for all target PAHs, with benzoanthracene and chrysene at 91 plusminus 4 percent and benzochrysene at 83 plusminus 8 percent. Integration of the HPLC direct injection module extends run time to 1 hour 45 minutes but eliminates manual vial transfer, achieving recoveries above 93 percent for all compounds. Overlay of fluorescence chromatograms demonstrates excellent separation and reproducibility against external standards.

Benefits and practical applications

• Fully automated sample cleanup and analysis reduces hands on time and potential errors
• High throughput and consistent recoveries support routine monitoring of PAHs in food matrices
• On-line concentration and solvent exchange enhance sensitivity and method robustness
• Flexible configuration allows direct injection or vial-based workflows

Future trends and application opportunities

Further development may include adapting the workflow for additional analyte classes, coupling with mass spectrometric detection for comprehensive screening, and miniaturizing the evaporation module to reduce solvent consumption. Integration with data processing algorithms will facilitate real-time QAQC and method optimization.

Conclusion

The described GPC-EVAporation-HPLC-FLD workflow provides an efficient, reproducible, and automated solution for the determination of PAHs in complex food extracts. It meets regulatory requirements and enhances laboratory productivity by minimizing manual steps while ensuring high recovery rates and sensitive detection.