Packed-nanofiber solid phase extraction for daidzein, genistein, glycitein in human urine and their simultaneous detection†

In this work, an integrated method based on the novel packed-fiber solid-phase extraction (PFSPE) combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) detection system was proposed for the detection of daidzein, genistein and glycitein in human urine. To efficiently adsorb three kinds of isoflavones in biological fluid, polystyrene-based nanofibers were prepared and used as adsorbents in customized solid phase extraction devices. The composition of the nanofibers, the amount of different salt ions added, the type of eluent, and the interaction of eluent volume, the amounts of nanofibers added, and the extraction time were analyzed to find the optimal adsorption conditions, respectively. The method of optimal extraction conditions for the analysis of three soy isoflavones exhibited low limits of detection (LOD) and limits of quantitation (LOQ) of 1.68–2.74 μg L⁻¹ and 5.09–8.3 μg L⁻¹, respectively, and spiked recovery of 95.2–107.1%, and has been successfully applied to human urine samples. This study demonstrated the potential of PFSPE as methods for the adsorption and detection of daidzein, genistein, glycitein in biological fluid concurrently, providing a valuable tool for pharmacokinetic studies and investigations into the metabolism and bioavailability of isoflavones.