Detecting PAHs with Electromembrane Extraction and Liquid Chromatography

News
Article

A study published in late 2024 by researchers from the Henan Academy of Sciences in Zhengzhou, China showed how hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) can be determined using electromembrane extraction coupled with liquid chromatography. Their findings were published in the Journal of Chromatography A (1).

Professional laboratory sample processor pump | Image Credit: © Sergey Ryzhov - stock.adobe.com

Professional laboratory sample processor pump | Image Credit: © Sergey Ryzhov - stock.adobe.com

Polycyclic aromatic hydrocarbons (PAHs) are a class of compounds with fused aromatic rings recognized as environmental contaminants stemming from incomplete combustion of organic matter, that are widely distributed in aqueous, air, and solid samples. They can also occur naturally in coal, crude oil, and gasoline (2). PAHs are primary pollutants according to the United States Environmental Protection Agency (U.S. EPA), and they can enter the body through direct ingestion, dermal contact, or inhalation. Efforts to determine and regulate PAHs have existed since at least the 1990s, and chromatography techniques including gas chromatography–mass spectrometry (GC–MS) have played an important role in their detection (3).

Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are metabolites of persistent organic pollutants formed during the bioactivation process of biological matrices (4). Many studies demonstrate that PAHs can be rapidly metabolized and produce OH-PAHs in vivo after exposure, and then may be further biotransformed to reactive electrophiles, which can bind covalently to DNA causing gene mutation and carcinogenity.

In this study, electromembrane extraction (EME) is proposed as a simple, effective, and ecofriendly sample pretreatment technique for the selective extraction, purification and enrichment of four typical OH-PAHs (2-naphthol, 2- and 3-phenanthrol, 2-hydroxyfluorene) in human urine for the first time. EME is a miniaturized liquid phase extraction technique, using an electrical field to drive analytes from a sample (donor phase) to an acceptor phase through a hydrophobic membrane containing a supported organic solvent on its porous membrane (5). With prior tests existing to detect proteins in urine, this led to the substance being used for this experiment (6).

The team developed a method combining EME with high-performance liquid chromatography (HPLC). Factors that were considered include type of SLM solvent, pH value of acceptor phase, extraction voltage and extraction time were investigated for high EME efficiency. This technique provided wide linear ranges for four OH-PAHs from 1–500 ng mL-1 with low LODs of 0.05–0.3 ng mL-1. The average recoveries of four OH-PAHs at three spiked levels in human urine were 81.6–102.5% with RSDs all below 9.4%. The method was also successfully applied for the sensitive determination of trace four OH-PAHs in urine samples from non-smokers and smokers with a maximum concentration of 2.24 and 3.56 ng mL-1, respectively. These findings show potential for analyzing trace OH-PAHs in biological samples.

Overall, the EME-HPLC method was shown to be useful in detecting trace OH-PAHs in urine samples. By offering numerous advantages over other techniques with similar uses, it shows potential for detecting trace OH-PAHs in not only urine, but potentially in other types of biological samples.

References

(1) Gao, H.; Gao, S.; Lv, M. Liu, Y.; et al. Determination of Hydroxypolycyclic Aromatic Hydrocarbons in Urine by Electromembrane Extraction Coupled with Liquid Chromatography. J. Chromatogr. A 2024, 1736, 465375. DOI: 10.1016/j.chroma.2024.465375

(2) Polycyclic Aromatic Hydrocarbons (PAHs). CDC 2014. https://www.epa.gov/sites/default/files/2014-03/documents/pahs_factsheet_cdc_2013.pdf (accessed 2025-1-28)

(3) Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Ambient Air Using Gas Chromatography/Mass Spectrometry (GC/MS). U.S. Environmental Protection Agency 1999. https://www.epa.gov/sites/default/files/2019-11/documents/to-13arr.pdf (accessed 2025-1-29)

(4) León-Morán, L.; Pastor-Belda, M.; Campillo, N.; et al. Monitoring of Hydroxylated Polycyclic Aromatic Hydrocarbons in Human Tissues: Targeted and Untargeted Approaches Using Liquid Chromatography-High Resolution Mass Spectrometry. J. Sep. Sci. 2023, 46 (17), 2330207. DOI: 10.1002/jssc.202300207

(5) Martins, R. O.; de Araújo, G. L.; Simas, R. C.; Chaves, A. R. Electromembrane Extraction (EME): Fundamentals and Applications. Talanta Open 2023, 7, 100200. DOI: 10.1016/j.talo.2023.100200

(6) Protein Urine Test. Mount Sinai 2023. https://www.mountsinai.org/health-library/tests/protein-urine-test (accessed 2025-1-29)

Related Content