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

Importance of the topic

Polyaromatic hydrocarbons (PAHs) are persistent organic pollutants found in food and environmental samples. Their potential carcinogenic and mutagenic properties require reliable analytical methods to ensure safety and regulatory compliance. A rapid, automated approach to isolate, concentrate and quantify PAHs enhances throughput and reproducibility in quality control and research laboratories.

Objectives and Study Overview

This application note demonstrates an integrated workflow combining gel permeation chromatography (GPC) with on-line evaporation and high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The aim is to automate sample preparation, solvent exchange and sensitive PAH measurement in a single sequence, reducing manual handling and analysis time.

Methodology and Instrumentation

The protocol begins with an extracted, dried and filtered sample adjusted to 10.0 mL in a 16 mL vial. A 5.0 mL aliquot is loaded onto the FREESTYLE GPC system via an automated loop. As the matrix components elute, the target PAH fraction is directed into the EVAporation module, where on-line concentration and solvent exchange to acetonitrile/1 % 1-butanol occur. The final volume is adjusted to 1.0 mL and transferred to an HPLC vial for injection.

Used Instrumentation

• FREESTYLE BASIC system with GPC module and EVAporation module
• GPC column (P/N GPC10011)
• Thermo Scientific Ultimate 3000 HPLC with fluorescence detector
• Solvents: ethyl acetate/cyclohexane, acetonitrile with 1 % 1-butanol

Results and Discussion

The complete sample preparation cycle, including solvent exchange, requires approximately 1 hour 35 minutes. Omitting the solvent exchange for direct GC measurement reduces the time by at least ten minutes. Recovery experiments (n = 3) yielded:

• Benzo[a]anthracene/Chrysene: 91 ± 4 %
• Benzo[b]fluoranthene: 90 ± 4 %
• Benzo[a]pyrene: 85 ± 5 %
• Benzo[chrysene]: 83 ± 8 %

Overlayed fluorescence chromatograms comparing an external PAH standard and a processed sample confirm the method’s sensitivity and selectivity.

Benefits and Practical Applications

The fully automated GPC–EVAporation–HPLC-FLD workflow offers:

• Reduced hands-on time and contamination risk
• High recovery and reproducibility for key PAHs
• Flexible solvent exchange enabling compatibility with GC or HPLC
• Enhanced throughput for routine environmental and food safety testing

Future Trends and Opportunities

Further integration with mass spectrometric detectors could broaden analyte scope. Miniaturization of evaporation chambers and parallel processing modules may further shorten cycle times. Development of standardized consumables and AI-driven method optimization could enhance robustness and ease of use.

Conclusion

This application demonstrates a streamlined, automated workflow for PAH determination, combining effective GPC clean-up, on-line concentration and sensitive HPLC-FLD analysis. The method achieves high recovery, reproducibility and reduced analysis time, supporting reliable QA/QC in various industries.

Reference

LCTech GmbH. Determination of PAH via GPC with on-line EVAporation and HPLC-FLD Measurement. Application Note AN004. November 2019.