Preparation of Fe3O4/NiAl LDH/MIL-125 (Ti) and evaluation for selective extraction and determination of organophosphorus flame retardants in environmental water samples

In this work, a novel composite Fe 3 O 4 /NiAl LDH/MIL-125 (Ti) was developed through modifying the Ti-based MOF into magnetic NiAl LDH materials and applied to efficiently extract organophosphorus flame retardants (OPFRs) from water samples. The prepared Fe 3 O 4 /NiAl LDH presented good extraction efficiency for OPFRs, and, electrostatic interaction and π-π interaction also played an important role for the extraction process, except for the selective metal-affinity coordination between the adsorbents and OPFRs. Some key factors influencing the magnetic solid-phase extraction efficiency were explored, including adsorbent amount, ultrasound time, solution pH, salt content, the type of elution solvent and eluent volume. Under the optimal conditions, the coefficients of determination (R 2 ) of the OPFRs were 0.9976–0.9996, and the limits of detection (S/N = 3) and limits of quantification (S/N = 10) were respectively 0.3–1.0 μg·L −1 and 1.0–3.0 μg·L −1 . The developed approach was applied for the extraction and determination of OPFRs in the environmental water samples, and the spiked recoveries ranged from 82.79 % to 111.32 %.