Determination of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) in Water Samples Using On-Line Sample Concentration, Reversed-Phase Liquid Chromatography, and Suppressed Conductivity Detection

Význam tématu

Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are persistent, bioaccumulative anionic environmental contaminants widely used in industrial and consumer products. Their resistance to degradation and potential toxicity at trace levels have triggered regulatory scrutiny, motivating the development of sensitive, cost-effective analytical methods for water monitoring.

Cíle a přehled studie

The technical note describes a validated methodology for trace determination of PFOA and PFOS in aqueous samples. The approach integrates on-line sample concentration, reversed-phase liquid chromatography, and suppressed conductivity detection. Key objectives include achieving nanogram detection limits, a wide dynamic range, and robust performance in various water matrices.

Použitá metodika a instrumentace

An ICS-3000 system was configured with a DP dual gradient pump, DC detector/chromatography module with suppressed conductivity detection, an AMMS 300 2 mm anion suppressor, and a WPS-3000SL autosampler with a 1 mL loop. A peristaltic pump delivered regenerant to the suppressor. Chromeleon 6.7 managed system control and data acquisition. On-line concentration used an Acclaim PA2 guard cartridge (5 µm, 4.3×10 mm) and an analytical Acclaim PA2 column (3 µm, 2.1×150 mm) at 30 °C. Mobile phases comprised acetonitrile, 100 mM borate buffer (pH 8.0), and water. A gradient program and valve switching sequence enabled sample loading, matrix wash, and elution in a single run.

Hlavní výsledky a diskuse

Detection limits near 1 ng per injection were achieved by preconcentrating 1 mL samples. The method offered dynamic linearity from 1 to 40 000 µg/L using quadratic calibration at low levels (0.002–0.20 µg/mL, R2>0.99) and linear calibration at higher concentrations. Recoveries in tap and bottled water ranged from 97% to 112% for spiked levels between 2 and 200 µg/L. Filter selection proved critical: PTFE and polysulfone membranes provided quantitative recovery, whereas nylon trapped analytes. Fluorocarbon sample paths were replaced with PEEK or stainless steel to avoid adsorption and carryover of fluorinated analytes.

Přínosy a praktické využití metody

• High sensitivity and selectivity for PFOA and PFOS at trace levels.
• Wide dynamic range suitable for compliance testing and environmental surveys.
• Cost-effective operation compared to mass spectrometry, with minimal matrix interferences.
• On-line concentration streamlines sample preparation and reduces manual handling.

Budoucí trendy a možnosti využití

The technique can be extended to other perfluorocarboxylic acids (C6–C18) and hydrophobic anions such as anionic surfactants. Future developments may include coupling with tandem mass spectrometry for structural confirmation, further miniaturization of concentrator assemblies, and integration into automated field-deployable platforms.

Závěr

The presented HPLC method offers a robust, economical, and sensitive solution for quantifying PFOA and PFOS in water. By combining on-line concentration with suppressed conductivity detection, it meets stringent trace-level requirements and supports routine environmental monitoring.

Reference

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