Hollow microporous organic network fiber membrane for efficient extraction of okadaic acid from marine organisms

Membrane-based micro-solid phase extraction (M-μSPE) has garnered great attention in sample pretreatment, suffering an inherent contradiction between permeability and adsorption capacity. In this study, a pure microporous organic network (TEB-DIB-MON) fiber membrane was prepared by combining electrostatic spinning technology, Sonogashira-Hagihara reaction and template sacrifice method. The prepared TEB-DIB-MON membrane exhibited a large specific surface area with a hollow and porous structure, thereby providing excellent solvent permeability and high adsorption capacity for okadaic acid (OA, an algal toxin). Under the optimized conditions, a sensitive analytical method was established by coupling M-μSPE with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The established method has a low detection limit (0.5 pg mL⁻¹), a wide linear range (1.5–1000 pg mL⁻¹, R ≥ 0.9991), and good reproducibility (RSD ≤ 9.4 %, n = 6), which was then successfully applied for OA detection in marine organisms. Trace amounts of OA (59.3–89.0 pg mL⁻¹⁾ was detected in the oyster and prawn samples. This work demonstrated that the excellent application potential of MON membranes in sample pretreatment, while also presents a novel synthesis strategy for MONs membranes.