Sensitive and Rapid Determination of Polycyclic Aromatic Hydrocarbons in Tap Water

Importance of the Topic

The determination of polycyclic aromatic hydrocarbons (PAHs) in drinking water is critical due to their toxicity, carcinogenic and mutagenic potential. Regulatory bodies worldwide set strict limits on PAH concentrations in environmental and drinking waters. Fast, reliable and sensitive analytical methods are essential to ensure water safety and compliance with regulations.

Study Goals and Overview

This study aimed to develop a rapid, sensitive and cost-effective high-performance liquid chromatography method with on-line solid-phase extraction (SPE) for the determination of 20 PAHs in tap water. The method replaces labor-intensive liquid-liquid extraction steps of EPA Methods 550 and 550.1 with automated on-line SPE, reducing sample preparation time and variability while maintaining or improving detection limits.

Methodology and Instrumentation

On-line SPE preconcentration was performed using an Acclaim PolarAdvantage II column to trap PAHs from filtered water samples. After enrichment, the analytes were back-flushed onto a Hypersil Green PAH analytical column for separation. A dual-pump RSLC configuration allowed simultaneous sample loading and column equilibration. Detection combined UV absorbance at 254 nm for naphthalene and acenaphthylene with programmed fluorescence wavelength switching for the remaining 18 PAHs, using three parallel emission channels to accommodate closely eluting compounds.

Instrumentation Used

• UltiMate 3000 Dual Rapid Separation LC system with DGP-3600RS dual gradient pump and SRD-3600 solvent/degasser rack
• WPS-3000TRS well-plate autosampler with 1000 µL loop and syringe
• Thermostatted Column Compartment (TCC-3000SD or TCC-3000RS)
• Acclaim PolarAdvantage II SPE column (3 µm, 4.6 × 50 mm)
• Hypersil Green PAH analytical column (3 µm, 3.0 × 150 mm)
• DAD-3000RS diode array detector and FLD-3400RS fluorescence detector
• Chromeleon CDS software v7.1 or above
• Target2 nylon syringe filters (0.45 µm)

Main Results and Discussion

The complete separation of all 20 PAHs was achieved within 35 minutes, compared to over 60 minutes in earlier reports. Method precision was excellent, with retention time RSD ≤ 0.16% and peak area RSD ≤ 1.3% for fluorescence detection (1 µg/L) and UV detection (10 µg/L). Calibration curves showed linearity over ranges of 0.05–100 µg/L (R² ≥ 0.995). Method detection limits (MDLs) ranged from 0.010 to 0.72 µg/L, calculated by the 99% confidence Student’s t-test. Spike recoveries in tap water at 0.05 and 5 µg/L levels fell between 80% and 120%, demonstrating good accuracy and matrix tolerance.

Benefits and Practical Applications

• Significant reduction in sample preparation time and labor by using automated on-line SPE
• Lower consumption of solvents and reagents compared to conventional extraction
• High sensitivity and reproducibility suitable for regulatory compliance
• Versatile detection combining UV and fluorescence for a broad range of PAHs
• Applicability to routine monitoring of drinking water, environmental quality and industrial effluents

Future Trends and Potential Applications

Advances in ultra-high-pressure LC (UHPLC) and improved stationary phases may further shorten analysis times and enhance resolution. Coupling with high-resolution mass spectrometry could enable simultaneous quantification and identification of emerging PAH derivatives and transformation products. Integration into fully automated workflows and remote monitoring systems will support large-scale water quality surveillance and rapid response to contamination events.

Conclusion

A robust on-line SPE-HPLC method has been demonstrated for the rapid, sensitive and reproducible determination of 20 PAHs in tap water. The method meets or exceeds performance criteria of established EPA protocols while offering faster turnaround and lower operational costs. Its flexibility and high throughput make it well suited for routine environmental and drinking water analysis.

References

1. Dionex Application Note 196: Determination of Polycyclic Aromatic Hydrocarbons in Edible Oils by Donor-Acceptor Complex Chromatography with Fluorescence Detection, 2008.
2. Dionex Application Note 213: Determination of Polycyclic Aromatic Hydrocarbons in Tap Water Using On-Line SPE Followed by HPLC with UV and Fluorescence Detection, 2009.
3. EPA Method 550: Determination of Polycyclic Aromatic Hydrocarbons in Drinking Water by Liquid-Liquid Extraction and HPLC with Coupled UV and Fluorescence Detection, 1990.
4. EPA Method 550.1: Determination of Polycyclic Aromatic Hydrocarbons in Drinking Water by Liquid-Solid Extraction and HPLC with Coupled UV and Fluorescence Detection, 1990.
5. EPA Method 610: Polynuclear Aromatic Hydrocarbons, 1982.
6. Dionex Technique Note 92: Combining Fluorescence Detection with UHPLC: An Overview of the Technical Requirements, 2011.