A Cu₇Mn₂ bimetallic cluster fiber coating for highly sensitive solid-phase microextraction of ten volatile phenolic...

A Cu₇Mn₂ bimetallic cluster (Cu₇Mn₂) fiber coating was prepared for headspace solid-phase microextraction (HS-SPME) of 10 phenolic compounds. The fiber coating was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption measurement, and thermogravimetric analysis. The adsorption performance was investigated via adsorption isotherm experiments. The results indicated that the adsorption of the Cu₇Mn₂ fiber coating for 10 phenolic compounds followed the Freundlich isotherm model, suggesting multilayer adsorption. Density functional theory (DFT) calculations revealed that the adsorption mechanism primarily involves hydrogen bonding, π - π stacking and hydrophobic interactions. After the extraction conditions were optimized, an HS-SPME-GC-FID method was established for the determination of 10 phenolic compounds in environmental water samples. The linear ranges were 0.003-500 μg·L^-1 for 2-NP, 0.009-500 μg·L^-1 for 2-CP, 0.015-500 μg·L^-1 for 2,4-DCP and 2,6-DCP, 0.030-500 μg·L^-1 for 2,4-DMP, 0.050-500 μg·L^-1 for PTBP, 0.100-500 μg·L^-1 for phenol and 3-MP, and 0.150-500 μg·L^-1 for 2-MP and 4-CP (R² ≥ 0.9908). The limits of detection (LODs, S/N=3) were 0.001-0.045 μg·L^-1. The recoveries of 10 phenolic compounds in water samples ranged from 80.2% to 119.8%. The enrichment factors ranged from 303 to 3435, and the coating could be reused at least 120 times. The established HS-SPME-GC-FID method is reliable for the determination of 10 phenolic compounds in real water samples.