An eco-friendly approach for determination of polycyclic aromatic compounds in water hyacinth (Eichhornia crassipes)

Water hyacinth (Eichhornia crassipes) is an aquatic plant capable of absorbing and accumulating organic pollutants and heavy metals from contaminated water bodies. In this study, a green miniaturized solid-liquid extraction combined with cleanup via dispersive micro-solid-phase extraction (MSLE-DμSPE) was developed and validated for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) in E. crassipes samples. The method was optimized in terms of both the extraction solvent and the adsorbent material used for cleanup. Under optimal conditions, the MSLE-DμSPE was validated considering the matrix-matched calibration, precision, limits of detection (LOD), quantification (LOQ) and accuracy. The LODs ranged from 0.38 to 1.05 ng g^-1, and the LOQs from 1.28 to 3.50 ng g^-1. Correlation coefficients (R²) ≥ 0.99 were obtained for all compounds within the linear range (0.5 to 30 μg L^-1). The mean recovery ranged from 79.7 % to 120 %, with intraday and interday relative standard deviations <20 %. Evaluation of the MSLE-DμSPE method using AGREEprep and BAGI metrics demonstrated the greenness and applicability of the developed method. Finally, the proposed method was successfully applied to water hyacinths collected from an estuary, and 17 PACs (9 PAHs and 9 PASHs) were identified and quantified, with concentrations ranging from 0.3 ± 0.1 ng g^-1 (anthracene) to 169 ± 16 ng g^-1 (benzo[a]pyrene) for PAHs, and from 1.8 ± 0.8 ng g^-1 (2,4-dimethyldibenzothiophene) to 730 ± 24 ng g^-1 (2,3-dimethylbenzothiophene) for PASHs. Benzo[a]pyrene, benzo[b]fluoranthene, coronene, dibenzothiophene, and 2,3-dimethylbenzothiophene were the most abundant in both the aerial parts and roots of the plant.