A porphyrin-based polyhydroxylated porous organic polymer for solid-phase microextraction of sulfonamide antibiotics...

The extensive use of sulfonamide antibiotics (SAs) has led to their pervasive presence in environmental and food matrices, posing potential risks to ecosystems and human health. Consequently, there is a pressing need for robust analytical techniques capable of their sensitive determination. To address this challenge, we herein report a novel porous organic polymer (POP) incorporating porphyrin units and rich hydroxyl groups. A series of POPs were synthesized via a facile aqueous route under compelling mild conditions by varying the molar ratio of 5,10,15,20-Tetra(3-hydroxyphenyl) porphyrin to 4,4'-diaminodiphenylsulfone (1:2, 1:4, and 1:6), among which the 1:6 formulation exhibited optimal extraction performance, surpassing both other ratios and a control POP prepared with benzidine. The prepared POPs demonstrated 8 to 486-fold higher extraction efficiency than commercial fibers, attributed to the synergistic combination of multiple hydrogen bonds, π-π stacking interactions, and electrostatic attractions between the hydrophilic coating and the target analytes. To achieve optimal analytical performance, key solid-phase microextraction (SPME) parameters were systematically investigated, with optimal conditions established as follows: extraction time of 30 min, desorption time of 20 min, extraction temperature of 30 °C, stirring rate of 700 rpm, ionic strength of 15%, and pH 8. Under these conditions, the developed SPME-HPLC-MS/MS method exhibited wide linear ranges (0.1-500 ng mL^-1, R² > 0.9991), low limits of detection (LODs: 0.01-0.06 ng mL^-1), and satisfactory precision (relative standard deviations: 3.0-8.3%). The obtained LODs are substantially lower than those of the Chinese national standard method (HJ 1398-2024, 3-6 μg mL^-1). The practical applicability of the method was further validated through the analysis of river, lake, and rainwater samples, yielding satisfactory recoveries ranging from 80.6% to 114%.