Analysis of Polynuclear Aromatic Hydrocarbons (PAHs) in Water with ZORBAX Eclipse PAH Column

Significance of the Topic

Polynuclear aromatic hydrocarbons (PAHs) are widespread environmental contaminants known for their carcinogenic, mutagenic and teratogenic properties. They originate from incomplete combustion of organic matter and are strictly regulated in water by agencies such as the U.S. EPA and NIOSH, requiring robust analytical methods for trace-level monitoring.

Objectives and Study Overview

The study aims to develop and validate a sensitive, reproducible HPLC method for the quantification of 17 priority PAHs in water. It combines solid-phase extraction (SPE) using AccuBond ODS C18 cartridges with separation on an Agilent ZORBAX Eclipse PAH column, employing diode-array (DAD) and fluorescence (FLD) detection.

Instrumentation Used

• Agilent 1200SL Rapid Resolution HPLC system: G1312B binary pump, G1379B degasser, G1367C autosampler, G1316B column compartment, G1315C DAD, G1321A FLD
• ZORBAX Eclipse PAH column, 4.6 mm × 150 mm, 3.5 µm (p/n 959963-918)
• AccuBond ODS C18 SPE cartridge (0.5 g, p/n 188-1356)

Methodology

One-liter water samples are conditioned and extracted via SPE, eluted with dichloromethane, concentrated and reconstituted in acetonitrile. Chromatographic separation is achieved with a water–acetonitrile gradient (50% to 100% B over 22 min) at 1.5 mL/min. DAD detection is set at 254 nm; FLD employs a wavelength program optimized for each PAH to achieve low picogram limits of detection.

Main Results and Discussion

The Eclipse PAH column baseline resolves all 17 PAHs, including five groups of geometric isomers, with resolution factors >2.0 for the closest peaks. FLD provides ~100-fold better signal-to-noise than DAD, yielding detection limits in the low picogram range. Retention time precision is better than 0.1% RSD and peak area RSD is <2%. Linearity is excellent (r² ≥ 0.9990) over trace-level concentration ranges. Recoveries in spiked water range from 35% to 101% depending on compound volatility and solubility; volatile PAHs benefit from tube-heater concentration.

Benefits and Practical Applications of the Method

• High sensitivity and low detection limits for regulatory compliance in drinking and wastewater
• Robust separation of isomeric PAHs enabled by the specialized bonded phase
• Reproducible retention times and peak areas support reliable identification and quantification
• SPE sample preparation offers concentration of trace analytes from large volumes

Future Trends and Opportunities

Further improvements may include integration with LC-MS/MS for confirmatory analysis, automation of SPE workflows, exploration of alternative extraction solvents to enhance recovery of low-solubility PAHs, and expansion of monitored compounds to emerging polycyclic contaminants.

Conclusion

The combined SPE–HPLC method using the ZORBAX Eclipse PAH column demonstrates superior selectivity, sensitivity and reproducibility for the analysis of 17 regulated PAHs in water. It meets stringent regulatory requirements and provides a reliable platform for routine environmental monitoring.

References

1. Prest H. Solid-phase extraction and retention-time locked GC/MS analysis of selected polycyclic aromatic hydrocarbons (PAHs). Agilent Technologies; 2002. Publication 5988-7150EN.
2. United States Environmental Protection Agency. Method 610: Determination of polycyclic aromatic hydrocarbons in municipal and industrial wastewater. EPA Environmental Monitoring Systems Laboratory; 1982.
3. United States Environmental Protection Agency. Method 550.1: Determination of polycyclic aromatic hydrocarbons in drinking water by liquid-solid extraction and HPLC with coupled ultraviolet and fluorescence detection. EPA Environmental Monitoring Systems Laboratory; 1990.
4. United States Environmental Protection Agency. Method 8310: Determination of polycyclic aromatic hydrocarbons in ground water and wastes. EPA Environmental Monitoring Systems Laboratory; 1986.
5. National Institute for Occupational Safety and Health. Manual of Analytical Methods (NMAM), 4th ed., Method 5506: Polynuclear aromatic hydrocarbons by HPLC. NIOSH; 1998.
6. Sun. Determination of 16 polycyclic aromatic hydrocarbons by liquid chromatography with solid phase extraction (II). J Univ Sci Technol Suzhou. 2006;19(4):43–48.