Quantifying PAHs in water by three-way fluorescence spectra and second-order calibration methods

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in natural water is hindered by their low solubility, varying fluorescence intensities, and complex environmental interferents.
• Traditional fluorescence techniques often struggle to provide precise measurements in complex aquatic matrices.

Purpose of the Study:

• To develop and evaluate advanced chemometric methods for accurate determination of PAH concentrations in reservoir and river water.
• To compare the predictive performance of three-way parallel factor analysis, multi-way partial least square with residual bilinearization, and unfolded partial least square with residual bilinearization for PAH analysis.

Main Methods:

• Utilized three-way fluorescence spectra data.
• Applied three advanced chemometric methods: three-way parallel factor analysis (3-way PARAFAC), multi-way partial least square with residual bilinearization (MPLS-RB), and unfolded partial least square with residual bilinearization (U-PLS-RB).
• Validated method performance using independent validation sets to assess prediction accuracy for various PAHs.

Main Results:

• The unfolded partial least square with residual bilinearization (U-PLS-RB) method demonstrated superior performance in predicting PAH concentrations.
• U-PLS-RB achieved high accuracy with relative errors ≤6% for phenanthrene, pyrene, anthracene, and fluorene.
• For acenaphthene and fluoranthene, U-PLS-RB showed acceptable accuracy with relative errors ≤35% across different water backgrounds.

Conclusions:

• The U-PLS-RB method offers a robust and accurate approach for quantifying PAHs in complex environmental water samples.
• Three-way fluorescence coupled with U-PLS-RB overcomes limitations of traditional methods, enabling reliable PAH monitoring at μg L⁻¹ levels.
• This study highlights the potential of advanced multi-way chemometric techniques for environmental water quality assessment.